Sample records for big-bang nucleosynthesis bbn

  1. Big Bang Nucleosynthesis: 2015

    E-Print Network [OSTI]

    Cyburt, Richard H; Olive, Keith A; Yeh, Tsung-Han

    2015-01-01T23:59:59.000Z

    Big-bang nucleosynthesis (BBN) describes the production of the lightest nuclides via a dynamic interplay among the four fundamental forces during the first seconds of cosmic time. We briefly overview the essentials of this physics, and present new calculations of light element abundances through li6 and li7, with updated nuclear reactions and uncertainties including those in the neutron lifetime. We provide fits to these results as a function of baryon density and of the number of neutrino flavors, N_nu. We review recent developments in BBN, particularly new, precision Planck cosmic microwave background (CMB) measurements that now probe the baryon density, helium content, and the effective number of degrees of freedom, n_eff. These measurements allow for a tight test of BBN and of cosmology using CMB data alone. Our likelihood analysis convolves the 2015 Planck data chains with our BBN output and observational data. Adding astronomical measurements of light elements strengthens the power of BBN. We include a ...

  2. Big-Bang Nucleosynthesis verifies classical Maxwell-Boltzmann distribution

    E-Print Network [OSTI]

    S. Q. Hou; J. J. He; A. Parikh; K. Daid; C. Bertulani

    2014-08-15T23:59:59.000Z

    We provide the most stringent constraint to date on possible deviations from the usually-assumed Maxwell-Boltzmann (MB) velocity distribution for nuclei in the Big-Bang plasma. The impact of non-extensive Tsallis statistics on thermonuclear reaction rates involved in standard models of Big-Bang Nucleosynthesis (BBN) has been investigated. We find that the non-extensive parameter $q$ may deviate by, at most, $|\\delta q|$=6$\\times$10$^{-4}$ from unity for BBN predictions to be consistent with observed primordial abundances; $q$=1 represents the classical Boltzmann-Gibbs statistics. This constraint arises primarily from the {\\em super}sensitivity of endothermic rates on the value of $q$, which is found for the first time. As such, the implications of non-extensive statistics in other astrophysical environments should be explored. This may offer new insight into the nucleosynthesis of heavy elements.

  3. The NACRE Thermonuclear Reaction Compilation and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Richard H. Cyburt; Brian D. Fields; Keith A. Olive

    2001-05-17T23:59:59.000Z

    The theoretical predictions of big bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction cross sections. In this paper, we examine the impact on BBN of the recent compilation of nuclear data and thermonuclear reactions rates by the NACRE collaboration. We confirm that the adopted rates do not make large overall changes in central values of predictions, but do affect the magnitude of the uncertainties in these predictions. Therefore, we then examine in detail the uncertainties in the individual reaction rates considered by NACRE. When the error estimates by NACRE are treated as 1\\sigma limits, the resulting BBN error budget is similar to those of previous tabulations. We propose two new procedures for deriving reaction rate uncertainties from the nuclear data: one which sets lower limits to the error, and one which we believe is a reasonable description of the present error budget. We propagate these uncertainty estimates through the BBN code, and find that when the nuclear data errors are described most accurately, the resulting light element uncertainties are notably smaller than in some previous tabulations, but larger than others. Using these results, we derive limits on the cosmic baryon-to-photon ratio $\\eta$, and compare this to independent limits on $\\eta$ from recent balloon-borne measurements of the cosmic microwave background radiation (CMB). We discuss means to improve the BBN results via key nuclear reaction measurements and light element observations.

  4. Big Bang Nucleosynthesis with Independent Neutrino Distribution Functions

    E-Print Network [OSTI]

    Christel J. Smith; George M. Fuller; Michael S. Smith

    2008-12-06T23:59:59.000Z

    We have performed new Big Bang Nucleosynthesis calculations which employ arbitrarily-specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these distributions to the thermodynamics, the expansion rate and scale factor-time/temperature relationship, as well as to all relevant weak, electromagnetic, and strong nuclear reaction processes in the early universe. With this approach, we can treat any scenario in which neutrino or antineutrino spectral distortion might arise. These scenarios might include, for example, decaying particles, active-sterile neutrino oscillations, and active-active neutrino oscillations in the presence of significant lepton numbers. Our calculations allow lepton numbers and sterile neutrinos to be constrained with observationally-determined primordial helium and deuterium abundances. We have modified a standard BBN code to perform these calculations and have made it available to the community.

  5. Effects of a torsion field on Big Bang nucleosynthesis

    E-Print Network [OSTI]

    M. Brüggen

    1999-06-25T23:59:59.000Z

    In this paper it is investigated whether torsion, which arises naturally in most theories of quantum gravity, has observable implications for the Big Bang nucleosynthesis. Torsion can lead to spin flips amongst neutrinos thus turning them into sterile neutrinos. In the early Universe they can alter the helium abundance which is tightly constrained by observations. Here I calculate to what extent torsion of the string theory type leads to a disagreement with the Big Bang nucleosynthesis predictions.

  6. Refined scenario of standard Big Bang nucleosynthesis allowing for nonthermal nuclear reactions in the primordial plasma

    SciTech Connect (OSTI)

    Voronchev, Victor T.; Nakao, Yasuyuki; Nakamura, Makoto; Tsukida, Kazuki [Institute of Nuclear Physics, Moscow State University, Moscow 119991 (Russian Federation); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan); Division of Advanced Plasma Research, Japan Atomic Energy Agency, 2-166 Oaza-Obuchi-Aza-Omotedate, Rokkasho, Kamikita, Aomori 039-3212 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Motooka, Fukuoka 819-0395 (Japan)

    2012-11-12T23:59:59.000Z

    The standard scenario of big bang nucleosynthesis (BBN) is generalized to take into account nonthermal nuclear reactions in the primordial plasma. These reactions are naturally triggered in the BBN epoch by fast particles generated in various exoergic processes. It is found that, although such particles can appreciably enhance the rates of some individual reactions, their influence on the whole process of element production is not significant. The nonthermal corrections to element abundances are obtained to be 0.1% ({sup 3}H), -0.03% ({sup 7}Li), and 0.34 %-0.63% (CNO group).

  7. Big Bang nucleosynthesis and the baryonic content of the universe

    E-Print Network [OSTI]

    T. X. Thuan; Y. I. Izotov

    2000-12-18T23:59:59.000Z

    A review of the latest measurements of the primordial abundances of the light nuclei D, 3He, 4He and 7Li is given. We discuss in particular the primordial abundance Yp of 4He as measured in blue compact dwarf galaxies. We argue that the best measurements now give a ``high'' value of Yp along with a ``low'' value of D/H, and that the two independent measurements are consistent within the framework of standard Big Bang nucleosynthesis with a number of light neutrino species Nnu = 3.0+/-0.3 (2sigma).

  8. STANDARD BIG BANG NUCLEOSYNTHESIS UP TO CNO WITH AN IMPROVED EXTENDED NUCLEAR NETWORK

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), CNRS/IN2P3, Universite Paris Sud, UMR 8609, Batiment 104, F-91405 Orsay Campus (France); Goriely, Stephane; Xu, Yi [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, CP 226, Boulevard du Triomphe, B-1050 Bruxelles (Belgium); Saimpert, Matthias; Vangioni, Elisabeth [Institut d'Astrophysique de Paris, UMR 7095 CNRS, Universite Pierre et Marie Curie, 98 bis Boulevard Arago, Paris 75014 (France)

    2012-01-10T23:59:59.000Z

    Primordial or big bang nucleosynthesis (BBN) is one of the three strong pieces of evidence for the big bang model together with the expansion of the universe and cosmic microwave background radiation. In this study, we improve the standard BBN calculations taking into account new nuclear physics analyses and enlarge the nuclear network up to sodium. This is, in particular, important to evaluate the primitive value of CNO mass fraction that could affect Population III stellar evolution. For the first time we list the complete network of more than 400 reactions with references to the origin of the rates, including Almost-Equal-To 270 reaction rates calculated using the TALYS code. Together with the cosmological light elements, we calculate the primordial beryllium, boron, carbon, nitrogen, and oxygen nuclei. We performed a sensitivity study to identify the important reactions for CNO, {sup 9}Be, and boron nucleosynthesis. We re-evaluated those important reaction rates using experimental data and/or theoretical evaluations. The results are compared with precedent calculations: a primordial beryllium abundance increase by a factor of four compared to its previous evaluation, but we note a stability for B/H and for the CNO/H abundance ratio that remains close to its previous value of 0.7 Multiplication-Sign 10{sup -15}. On the other hand, the extension of the nuclear network has not changed the {sup 7}Li value, so its abundance is still 3-4 times greater than its observed spectroscopic value.

  9. Primordial Lithium Abundance in Catalyzed Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Chris Bird; Kristen Koopmans; Maxim Pospelov

    2008-05-19T23:59:59.000Z

    There exists a well known problem with the Li7+Be7 abundance predicted by standard big bang nucleosynthesis being larger than the value observed in population II stars. The catalysis of big bang nucleosynthesis by metastable, \\tau_X \\ge 10^3 sec, charged particles X^- is capable of suppressing the primordial Li7+Be7, abundance and making it consistent with the observations. We show that to produce the correct abundance, this mechanism of suppression places a requirement on the initial abundance of X^- at temperatures of 4\\times 10^8 K to be on the order of or larger than 0.02 per baryon, which is within the natural range of abundances in models with metastable electroweak-scale particles. The suppression of Li7+Be7, is triggered by the formation of (Be7X^-), compound nuclei, with fast depletion of their abundances by catalyzed proton reactions, and in some models by direct capture of X^- on Be7. The combination of Li7+Be7 and Li6 constraints favours the window of lifetimes, 1000s \\la tau_X \\leq 2000 s.

  10. Using Big Bang Nucleosynthesis to Extend CMB Probes of Neutrino Physics

    E-Print Network [OSTI]

    M. Shimon; N. J. Miller; C. T. Kishimoto; C. J. Smith; G. M. Fuller; B. G. Keating

    2010-05-10T23:59:59.000Z

    We present calculations showing that upcoming Cosmic Microwave Background (CMB) experiments will have the power to improve on current constraints on neutrino masses and provide new limits on neutrino degeneracy parameters. The latter could surpass those derived from Big Bang Nucleosynthesis (BBN) and the observationally-inferred primordial helium abundance. These conclusions derive from our Monte Carlo Markov Chain (MCMC) simulations which incorporate a full BBN nuclear reaction network. This provides a self-consistent treatment of the helium abundance, the baryon number, the three individual neutrino degeneracy parameters and other cosmological parameters. Our analysis focuses on the effects of gravitational lensing on CMB constraints on neutrino rest mass and degeneracy parameter. We find for the PLANCK experiment that total (summed) neutrino mass $M_{\

  11. Using Big Bang Nucleosynthesis to Extend CMB Probes of Neutrino Physics

    E-Print Network [OSTI]

    Shimon, M; Kishimoto, C T; Smith, C J; Fuller, G M; Keating, B G

    2010-01-01T23:59:59.000Z

    We present calculations showing that upcoming Cosmic Microwave Background (CMB) experiments will have the power to improve on current constraints on neutrino masses and provide new limits on neutrino degeneracy parameters. The latter could surpass those derived from Big Bang Nucleosynthesis (BBN) and the observationally-inferred primordial helium abundance. These conclusions derive from our Monte Carlo Markov Chain (MCMC) simulations which incorporate a full BBN nuclear reaction network. This provides a self-consistent treatment of the helium abundance, the baryon number, the three individual neutrino degeneracy parameters and other cosmological parameters. Our analysis focuses on the effects of gravitational lensing on CMB constraints on neutrino rest mass and degeneracy parameter. We find for the PLANCK experiment that total (summed) neutrino mass $M_{\

  12. Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets

    E-Print Network [OSTI]

    Lithium in cool stellar atmospheres: Big bang nucleosynthesis and extrasolar planets Matthias Steffen and Elisabetta Caffau Sternphysik In metal-poor stellar atmospheres, the Lithium line at 6707 Ã?-NLTE, respectively. The accurate spectroscopic determination of the Lithium abundance and in particular the 6Li/7Li

  13. Astrophysical S-factor for destructive reactions of lithium-7 in big bang nucleosynthesis

    SciTech Connect (OSTI)

    Komatsubara, Tetsuro; Kwon, YoungKwan; Moon, JunYoung; Kim, Yong-Kyun [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of); Moon, Chang-Bum [Hoseo University, Asan, Chungnam (Korea, Republic of); Ozawa, Akira; Sasa, Kimikazu; Onishi, Takahiro; Yuasa, Toshiaki; Okada, Shunsuke; Saito, Yuta [Division of Physics, University of Tsukuba, Tsukuba, Ibaraki (Japan); Hayakawa, Takehito; Shizuma, Toshiyuki [Japan Atomic Energy Agency, Shirakata Shirane, Tokai, Ibaraki (Japan); Kubono, Shigeru [RIKEN, Hirosawa, Wako, Saitama (Japan); Kusakabe, Motohiko [School of Liberal Arts and Science, Korea Aerospace University (Korea, Republic of); Kajino, Toshitaka [National Astronomical Observatory, Osawa, Mitaka, Tokyo (Japan)

    2014-05-02T23:59:59.000Z

    One of the most prominent success with the Big Bang models is the precise reproduction of mass abundance ratio for {sup 4}He. In spite of the success, abundances of lithium isotopes are still inconsistent between observations and their calculated results, which is known as lithium abundance problem. Since the calculations were based on the experimental reaction data together with theoretical estimations, more precise experimental measurements may improve the knowledge of the Big Bang nucleosynthesis. As one of the destruction process of lithium-7, we have performed measurements for the reaction cross sections of the {sup 7}L({sup 3}He,p){sup 9}Be reaction.

  14. A revised thermonuclear rate of $^{7}$Be($n$,$\\alpha$)$^{4}$He relevant to Big-Bang nucleosynthesis

    E-Print Network [OSTI]

    Hou, S Q; Kubono, S; Chen, Y S

    2015-01-01T23:59:59.000Z

    In the standard Big-Bang nucleosynthesis (BBN) model, the primordial $^7$Li abundance is overestimated by about a factor of 2--3 comparing to the astronomical observations, so called the pending cosmological lithium problem. The $^7$Be($n$,$\\alpha$)$^4$He reaction, which may affect the $^7$Li abundance, was regarded as the secondary important reaction in destructing the $^7$Be nucleus in BBN. However, the thermonuclear rate of $^7$Be($n$,$\\alpha$)$^4$He has not been well studied so far. This reaction rate was firstly estimated by Wagoner in 1969, which has been generally adopted in the current BBN simulations and the reaction rate library. This simple estimation involved only a direct-capture reaction mechanism, but the resonant contribution should be also considered according to the later experimental results. In this work, we have revised this rate based on the indirect cross-section data available for the $^4$He($\\alpha$,$n$)$^7$Be and $^4$He($\\alpha$,$p$)$^7$Li reactions, with the charge symmetry and deta...

  15. Big-Bang Nucleosynthesis and Gamma-Ray Constraints on Cosmic Strings with a large Higgs condensate

    E-Print Network [OSTI]

    H. F. Santana Mota; Mark Hindmarsh

    2015-01-06T23:59:59.000Z

    We consider constraints on cosmic strings from their emission of Higgs particles, in the case that the strings have a Higgs condensate with amplitude of order the string mass scale, assuming that a fraction of the energy of condensate can be turned into radiation near cusps. The injection of energy by the decaying Higgs particles affects the light element abundances predicted by standard Big-Bang Nucleosynthesis (BBN), and also contributes to the Diffuse Gamma-Ray Background (DGRB) in the universe today. We examine the two main string scenarios (Nambu-Goto and field theory), and find that the primordial Helium abundance strongly constrains the string tension and the efficiency of the emission process in the NG scenario, while the strongest BBN constraint in the FT scenario comes from the Deuterium abundance. The Fermi-LAT measurement of the DGRB constrains the field theory scenario even more strongly than previously estimated from EGRET data, requiring that the product of the string tension {\\mu} and Newton's constant G is bounded by G{\\mu} < 2.7x10^{-11}{\\beta}_{ft}^{-2}, where {\\beta}_{ft}^2 is the fraction of the strings' energy going into Higgs particles.

  16. A revised thermonuclear rate of $^{7}$Be($n$,$?$)$^{4}$He relevant to Big-Bang nucleosynthesis

    E-Print Network [OSTI]

    S. Q. Hou; J. J. He; S. Kubono; Y. S. Chen

    2015-02-13T23:59:59.000Z

    In the standard Big-Bang nucleosynthesis (BBN) model, the primordial $^7$Li abundance is overestimated by about a factor of 2--3 comparing to the astronomical observations, so called the pending cosmological lithium problem. The $^7$Be($n$,$\\alpha$)$^4$He reaction, which may affect the $^7$Li abundance, was regarded as the secondary important reaction in destructing the $^7$Be nucleus in BBN. However, the thermonuclear rate of $^7$Be($n$,$\\alpha$)$^4$He has not been well studied so far. This reaction rate was firstly estimated by Wagoner in 1969, which has been generally adopted in the current BBN simulations and the reaction rate library. This simple estimation involved only a direct-capture reaction mechanism, but the resonant contribution should be also considered according to the later experimental results. In this work, we have revised this rate based on the indirect cross-section data available for the $^4$He($\\alpha$,$n$)$^7$Be and $^4$He($\\alpha$,$p$)$^7$Li reactions, with the charge symmetry and detailed-balance principle. Our new result shows that the previous rate (acting as an upper limit) is overestimated by about a factor of ten. The BBN simulation shows that the present rate leads to a 1.2\\% increase in the final $^7$Li abundance compared to the result using the Wagoner rate, and hence the present rate even worsens the $^7$Li problem. By the present estimation, the role of $^7$Be($n$,$\\alpha$)$^4$He in destroying $^7$Be is weakened from the secondary importance to the third, and the $^7$Be($d$,$p$)2$^4$He reaction becomes of secondary importance in destructing $^7$Be.

  17. Lithium in Very Metal-poor Dwarf Stars - Problems for Standard Big Bang Nucleosynthesis?

    E-Print Network [OSTI]

    David L. Lambert

    2004-10-18T23:59:59.000Z

    The standard model of primordial nucleosynthesis by the Big Bang as selected by the WMAP-based estimate of the baryon density ($\\Omega_bh^2$) predicts an abundance of $^7$Li that is a factor of three greater than the generally reported abundance for stars on the Spite plateau, and an abundance of $^6$Li that is about a thousand times less than is found for some stars on the plateau. This review discusses and examines these two discrepancies. They can likely be resolved without major surgery on the standard model of the Big Bang. In particular, stars on the Spite plateau may have depleted their surface lithium abundance over their long lifetime from the WMAP-based predicted abundances down to presently observed abundances, and synthesis of $^6$Li (and $^7$Li) via $\\alpha + \\alpha$ fusion reactions may have occurred in the early Galaxy. Yet, there remain fascinating ways in which to remove the two discrepancies involving aspects of a new cosmology, particularly through the introduction of exotic particles.

  18. REVISED BIG BANG NUCLEOSYNTHESIS WITH LONG-LIVED, NEGATIVELY CHARGED MASSIVE PARTICLES: UPDATED RECOMBINATION RATES, PRIMORDIAL {sup 9}Be NUCLEOSYNTHESIS, AND IMPACT OF NEW {sup 6}Li LIMITS

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Kim, K. S. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Cheoun, Myung-Ki [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Kajino, Toshitaka [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kino, Yasushi [Department of Chemistry, Tohoku University, Sendai 980-8578 (Japan); Mathews, Grant J., E-mail: motohiko@kau.ac.kr, E-mail: kyungsik@kau.ac.kr, E-mail: cheoun@ssu.ac.kr, E-mail: kajino@nao.ac.jp, E-mail: y.k@m.tohoku.ac.jp, E-mail: gmathews@nd.edu [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2014-09-01T23:59:59.000Z

    We extensively reanalyze the effects of a long-lived, negatively charged massive particle, X {sup –}, on big bang nucleosynthesis (BBN). The BBN model with an X {sup –} particle was originally motivated by the discrepancy between the {sup 6,} {sup 7}Li abundances predicted in the standard BBN model and those inferred from observations of metal-poor stars. In this model, {sup 7}Be is destroyed via the recombination with an X {sup –} particle followed by radiative proton capture. We calculate precise rates for the radiative recombinations of {sup 7}Be, {sup 7}Li, {sup 9}Be, and {sup 4}He with X {sup –}. In nonresonant rates, we take into account respective partial waves of scattering states and respective bound states. The finite sizes of nuclear charge distributions cause deviations in wave functions from those of point-charge nuclei. For a heavy X {sup –} mass, m{sub X} ? 100 GeV, the d-wave ? 2P transition is most important for {sup 7}Li and {sup 7,} {sup 9}Be, unlike recombination with electrons. Our new nonresonant rate of the {sup 7}Be recombination for m{sub X} = 1000 GeV is more than six times larger than the existing rate. Moreover, we suggest a new important reaction for {sup 9}Be production: the recombination of {sup 7}Li and X {sup –} followed by deuteron capture. We derive binding energies of X nuclei along with reaction rates and Q values. We then calculate BBN and find that the amount of {sup 7}Be destruction depends significantly on the charge distribution of {sup 7}Be. Finally, updated constraints on the initial abundance and the lifetime of the X {sup –} are derived in the context of revised upper limits to the primordial {sup 6}Li abundance. Parameter regions for the solution to the {sup 7}Li problem and the primordial {sup 9}Be abundances are revised.

  19. High-energy break-up of 6Li as a tool to study the Big-Bang nucleosynthesis reaction 2H(alpha,gamma)6Li

    E-Print Network [OSTI]

    F. Hammache; M. Heil; S. Typel; D. Galaviz; K. Sümmerer; A. Coc; F. Uhlig; F. Attallah; M. Caamano; D. Cortina; H. Geissel; M. Hellström; N. Iwasa; J. Kiener; P. Koczon; B. Kohlmeyer; P. Mohr; E. Schwab; K. Schwarz; F. Schümann; P. Senger; O. Sorlin; V. Tatischeff; J. P. Thibaud; E. Vangioni; A. Wagner; W. Walus

    2010-11-29T23:59:59.000Z

    The recently claimed observations of non-negligible amounts of 6Li in old halo stars have renewed interest in the Big-Bang Nucleosynthesis (BBN) of 6Li. One important ingredient in the predicted BBN abundance of 6Li is the low-energy 2H(alpha,gamma)6Li cross section. Up to now, the only available experimental result for this cross section showed an almost constant astrophysical S-factor below 400 keV, contrary to theoretical expectations. We report on a new measurement of the 2H(alpha,gamma)6Li reaction using the break-up of 6Li at 150 A MeV. Even though we cannot separate experimentally the Coulomb contribution from the nuclear one, we find clear evidence for Coulomb-nuclear interference by analyzing the scattering-angular distributions. This is in-line with our theoretical description which indicates a drop of the S_24-factor at low energies as predicted also by most other models. Consequently, we find even lower upper limits for the calculated primordial 6Li abundance than before.

  20. A Reply to "Comment on 'Big Bang Nucleosynthesis and Active-Sterile Neutrino Mixing: Evidence for Maximal $?_?\\leftrightarrow?_?$ Mixing in Super Kamiokande?'"

    E-Print Network [OSTI]

    Xiangdong Shi; George M. Fuller

    1998-12-17T23:59:59.000Z

    In the paper "Big Bang Nucleosynthesis and Active-Sterile Neutrino Mixing: Evidence for Maximal Muon-Neutrino/Sterile-Neutrino Mixing in Super Kamiokande" (astro-ph/9810075), we suggested that to evade the Big Bang Nucleosynthesis exclusion of the muon neutrino to sterile neutrino oscillation explanation of the Super Kamiokande data, the tau neutrino must have a mass over about 15 eV and it must mix with a lighter sterile neutrino. A stable tau neutrino with this mass is inconsistent with cosmological structure formation. In a comment on our paper (astro-ph/9811067), Foot and Volkas argued that our result is incorrect and that the required tau neutrino mass should be much lower. Here we back up our original result with a more detailed calculation. We show that the argument of Foot and Volkas is invalid, most likely due to an insufficient energy resolution in the low energy part of the neutrino spectrum.

  1. New Constraints on Radiative Decay of Long-Lived Particles in Big Bang Nucleosynthesis with New $^4$He Photodisintegration Data

    E-Print Network [OSTI]

    Motohiko Kusakabe; Toshitaka Kajino; Takashi Yoshida; Tatsushi Shima; Yasuki Nagai; Toshiteru Kii

    2009-06-11T23:59:59.000Z

    A recent measurement of $^4$He photodisintegration reactions, $^4$He($\\gamma$,$p$)$^3$H and $^4$He($\\gamma$,$n$)$^3$He with laser-Compton photons shows smaller cross sections than those estimated by other previous experiments at $E_\\gamma \\lesssim 30$ MeV. We study big-bang nucleosynthesis with the radiative particle decay using the new photodisintegration cross sections of $^4$He as well as previous data. The sensitivity of the yields of all light elements D, T, $^3$He, $^4$He, $^6$Li, $^7$Li and $^7$Be to the cross sections is investigated. The change of the cross sections has an influence on the non-thermal yields of D, $^3$He and $^4$He. On the other hand, the non-thermal $^6$Li production is not sensitive to the change of the cross sections at this low energy, since the non-thermal secondary synthesis of $^6$Li needs energetic photons of $E_\\gamma \\gtrsim 50$ MeV. The non-thermal nucleosynthesis triggered by the radiative particle decay is one of candidates of the production mechanism of $^6$Li observed in metal-poor halo stars (MPHSs). In the parameter region of the radiative particle lifetime and the emitted photon energy which satisfies the $^6$Li production above the abundance level observed in MPHSs, the change of the photodisintegration cross sections at $E_\\gamma \\lesssim 30$ MeV as measured in the recent experiment leads to $\\sim 10$% reduction of resulting $^3$He abundance, whereas the $^6$Li abundance does not change for this change of the cross sections of $^4$He($\\gamma$,$p$)$^3$H and $^4$He($\\gamma$,$n$)$^3$He. The $^6$Li abundance, however, could show a sizable change and therefore the future precise measurement of the cross sections at high energy $E_\\gamma \\gtrsim$ 50 MeV is highly required.

  2. Verification of Maxwell-Boltzmann distribution with Big-Bang Nucleosyntheis theory

    E-Print Network [OSTI]

    S. Q. Hou; J. J. He; others

    2014-06-18T23:59:59.000Z

    The current Big-Bang Nucleosynthesis (BBN) model has been constructed based on a nuclear reaction network operating with thermal reactivities of Maxwell-Boltzmann (MB) distribution plasma. However, does the classical MB distribution still hold for the extremely high-temperature (in order of 10$^9$ K) plasma involved in the Big-Bang environment? In this work, we have investigated the impact of non-extensive Tsallis statistics (in $q$-Guassian distribution) on the thermonuclear reaction rates. We show for the first time that the reverse rates are extremely sensitive to the non-extensive $q$ parameter. Such sensitivity does not allow a large deviation of non-extensive distribution from the usual MB distribution. With a newly developed BBN code, the impact of primordial light-element abundances on $q$ values has been studied by utilizing the most recent BBN cosmological parameters and the available nuclear cross-section data. For the first time, we have accurately verified the microscopic MB distribution with the macroscopic BBN theory and bservation. By comparing the recent observed primordial abundances with our predictions, only a tiny deviation of $\\pm$6$\\times$10$^{-4}$ at most can be allowed for the MB distribution. However, validity of the classical statistics needs to be studied further for the self-gravitating stars and binaries of high-density environment, with the extreme sensitivity of reverse rate on $q$ found here.

  3. Before the Big Bang

    ScienceCinema (OSTI)

    Roger Penrose

    2010-09-01T23:59:59.000Z

    The second law of thermodynamics says, in effect, that things get more random as time progresses. Thus, we can deduce that the beginning of the universe - the Big Bang - must have been an extraordinarily precisely organized state. What was the nature of this state? How can such a special state have come about? In Penrose's talk, a novel explanation is suggested.

  4. A different Big Bang theory: Los Alamos

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    different Big Bang theory: Los Alamos unveils explosives detection expertise February 19, 2015 Collaboration project defeats explosives threats through enhanced detection...

  5. Monte-Carlo Analysis of Big Bang Production of Beryllium and Boron

    E-Print Network [OSTI]

    David Thomas

    1994-12-11T23:59:59.000Z

    There is continued interest in the possibility that big bang nucleosynthesis may produce significant quantities of Be and B. In this paper we reevaluate the primordial abundances taking into account uncertainties in reactions rates. We discuss the implications for primordial nucleosynthesis, and for galactic cosmic ray spallation.

  6. Cosmological solutions to the Lithium problem: Big-bang nucleosynthesis with photon cooling, $X$-particle decay and a primordial magnetic field

    E-Print Network [OSTI]

    Dai G. Yamazaki; Motohiko Kusakabe; Toshitaka Kajino; Grant. J. Mathews; Myung-Ki Cheoun

    2014-06-30T23:59:59.000Z

    The $^7$Li abundance calculated in BBN with the baryon-to-photon ratio fixed from fits to the CMB power spectrum is inconsistent with the observed lithium abundances on the surface of metal-poor halo stars. Previous cosmological solutions proposed to resolve this $^7$Li problem include photon cooling (possibly via the Bose-Einstein condensation of a scalar particle) or the decay of a long-lived $X-$particle (possibly the next-to-lightest supersymmetric particle). In this paper we reanalyze these solutions, both separately and in concert. We also introduce the possibility of a primordial magnetic field (PMF) into these models. We constrain the $X-$particles and the PMF parameters by the observed light element abundances using a likelihood analysis to show that the inclusion of all three possibilities leads to an optimum solution to the lithium problem. We deduce allowed ranges for the $X-$particle parameters and energy density in the PMF that can solve $^7$Li problem.

  7. Nuclear reaction rates and the primordial nucleosynthesis

    E-Print Network [OSTI]

    Abhishek Mishra; D. N. Basu

    2011-11-15T23:59:59.000Z

    The theoretical predictions of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) are dominated by uncertainties in the input nuclear reaction rates. We investigate the effect of modifying these reaction rates on light element abundance yields in BBN by replacing the thirty-five reaction rates out of the existing eighty-eight. We have studied these yields as functions of evolution time or temperature. We find that using these new reaction rates results in only a little increase in helium mass fraction over that obtained previously in BBN calculations. This allows insights into the role of the nuclear reaction rates in the setting of the neutron-to-proton ratio during the BBN epoch. We observe that even with considerable nuclear physics uncertainties, most of these nuclear reactions have minimal effect on the standard BBN abundance yields of $^6$Li and $^7$Li.

  8. Constraining Big Bang lithium production with recent solar neutrino data

    E-Print Network [OSTI]

    Takács, Marcell P; Szücs, Tamás; Zuber, Kai

    2015-01-01T23:59:59.000Z

    The 3He({\\alpha},{\\gamma})7Be reaction affects not only the production of 7Li in Big Bang nucleosynthesis, but also the fluxes of 7Be and 8B neutrinos from the Sun. This double role is exploited here to constrain the former by the latter. A number of recent experiments on 3He({\\alpha},{\\gamma})7Be provide precise cross section data at E = 0.5-1.0 MeV center-of-mass energy. However, there is a scarcity of precise data at Big Bang energies, 0.1-0.5 MeV, and below. This problem can be alleviated, based on precisely calibrated 7Be and 8B neutrino fluxes from the Sun that are now available, assuming the neutrino flavour oscillation framework to be correct. These fluxes and the standard solar model are used here to determine the 3He(alpha,gamma)7Be astrophysical S-factor at the solar Gamow peak, S(23+6-5 keV) = 0.548+/-0.054 keVb. This new data point is then included in a re-evaluation of the 3He({\\alpha},{\\gamma})7Be S-factor at Big Bang energies, following an approach recently developed for this reaction in the c...

  9. Compilation and R-matrix analysis of Big Bang nuclear reaction rates

    E-Print Network [OSTI]

    Pierre Descouvemont; Abderrahim Adahchour; Carmen Angulo; Alain Coc; Elisabeth Vangioni-Flam

    2004-07-06T23:59:59.000Z

    We use the R-matrix theory to fit low-energy data on nuclear reactions involved in Big Bang nucleosynthesis. A special attention is paid to the rate uncertainties which are evaluated on statistical grounds. We provide S factors and reaction rates in tabular and graphical formats.

  10. Effective dynamics of the matrix big bang

    SciTech Connect (OSTI)

    Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Instituut voor Theoretische Fysica, Universiteit van Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands); Rajaraman, Arvind [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Sethi, Savdeep [Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States)

    2006-05-15T23:59:59.000Z

    We study the leading quantum effects in the recently introduced matrix big bang model. This amounts to a study of supersymmetric Yang-Mills theory compactified on the Milne orbifold. We find a one-loop potential that is attractive near the big bang. Surprisingly, the potential decays very rapidly at late times where it appears to be generated by D-brane effects. Usually, general covariance constrains the form of any effective action generated by renormalization group flow. However, the form of our one-loop potential seems to violate these constraints in a manner that suggests a connection between the cosmological singularity and long wavelength, late time physics.

  11. Testing a Dilaton Gravity Model using Nucleosynthesis

    E-Print Network [OSTI]

    Sibel Boran; Emre Onur Kahya

    2014-09-05T23:59:59.000Z

    Big Bang Nucleosynthesis (BBN) offers one of the most strict evidences for the Lambda-CDM cosmology at present, as well as the Cosmic Microwave Background (CMB) radiation. In this work, our main aim is to present the outcomes of our calculations related to primordial abundances of light elements, in the context of higher dimensional steady-state universe model in the dilaton gravity. Our results show that abundances of light elements (primordial D, 3He, 4He, T, 7Li) are significantly different for some cases, and a comparison is given between a particular dilaton gravity model and Lambda-CDM in the light of the astrophysical observations.

  12. Space Time Quantization and the Big Bang

    E-Print Network [OSTI]

    B. G. Sidharth

    1998-06-21T23:59:59.000Z

    A recent cosmological model is recapitulated which deduces the correct mass, radius and age of the universe as also the Hubble constant and other well known apparently coincidental relations. It also predicts an ever expanding accelerating universe as is confirmed by latest supernovae observations. Finally the Big Bang model is recovered as a suitable limiting case.

  13. Constraints on Neutrino Oscillations from Big Bang Nucleosynethesis

    E-Print Network [OSTI]

    X. Shi; D. N. Schramm; B. D. Fields

    1993-07-16T23:59:59.000Z

    We discuss in detail the effect of neutrino oscillations in Big Bang nucleosynthesis, between active and sterile neutrinos, as well as between active and active neutrinos. We calculate the constraints on mixings between active and sterile neutrinos from the present observation of the primordial helium abundance and discuss the potential implications on various astrophysical and cosmological problems of such oscillations. In particular, we show that large angle sterile neutrino mixing seems to be excluded as a MSW solution to the solar neutrino situation or a solution to the atmospheric neutrino mixing hinted at in some underground experiments. We show how with this constraint, the next generation of solar neutrino experiments should be able to determine the resolution of the solar neutrino problem. It is also shown how sterile neutrinos remain a viable dark matter candidate.

  14. A different Big Bang theory: Los Alamos unveils explosives detection...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    unveils explosives detection expertise A different Big Bang theory: Los Alamos unveils explosives detection expertise A team of scientists is now rolling out a collaborative...

  15. Reheating and dangerous relics in pre-big bang string cosmology

    E-Print Network [OSTI]

    Alessandra Buonanno; Martin Lemoine; Keith A. Olive

    2000-09-27T23:59:59.000Z

    We discuss the mechanism of reheating in pre-big bang string cosmology and we calculate the amount of moduli and gravitinos produced gravitationally and in scattering processes of the thermal bath. We find that this abundance always exceeds the limits imposed by big-bang nucleosynthesis, and significant entropy production is required. The exact amount of entropy needed depends on the details of the high curvature phase between the dilaton-driven inflationary era and the radiation era. We show that the domination and decay of the zero-mode of a modulus field, which could well be the dilaton, or of axions, suffices to dilute moduli and gravitinos. In this context, baryogenesis can be accomodated in a simple way via the Affleck-Dine mechanism and in some cases the Affleck-Dine condensate could provide both the source of entropy and the baryon asymmetry.

  16. Primordial Beryllium as a Big Bang Calorimeter

    SciTech Connect (OSTI)

    Pospelov, Maxim [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5 (Canada)] [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 1A1 (Canada); Pradler, Josef [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5 (Canada)

    2011-03-25T23:59:59.000Z

    Many models of new physics including variants of supersymmetry predict metastable long-lived particles that can decay during or after primordial nucleosynthesis, releasing significant amounts of nonthermal energy. The hadronic energy injection in these decays leads to the formation of {sup 9}Be via the chain of nonequilibrium transformations: Energy{sub h}{yields}T, {sup 3}He{yields}{sup 6}He, {sup 6}Li{yields}{sup 9}Be. We calculate the efficiency of this transformation and show that if the injection happens at cosmic times of a few hours the release of O(10 MeV) per baryon can be sufficient for obtaining a sizable {sup 9}Be abundance. The absence of a plateau structure in the {sup 9}Be/H abundance down to a O(10{sup -14}) level allows one to use beryllium as a robust constraint on new physics models with decaying or annihilating particles.

  17. Primordial beryllium as a big bang calorimeter

    E-Print Network [OSTI]

    Maxim Pospelov; Josef Pradler

    2011-03-23T23:59:59.000Z

    Many models of new physics including variants of supersymmetry predict metastable long-lived particles that can decay during or after primordial nucleosynthesis, releasing significant amounts of non-thermal energy. The hadronic energy injection in these decays leads to the formation of ^9Be via the chain of non-equilibrium transformations: Energy_h -> T, ^3He -> ^6He, ^6Li -> ^9Be. We calculate the efficiency of this transformation and show that if the injection happens at cosmic times of a few hours, the release of 10 MeV per baryon can be sufficient for obtaining a sizable ^9Be abundance. The absence of a plateau-structure in the ^9Be/H abundance down to a 10^{-14} level allows one to use beryllium as a robust constraint on new physics models with decaying or annihilating particles.

  18. Big Bang Day: 5 Particles - 3. The Anti-particle

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

  19. Big Bang Day : The Great Big Particle Adventure - 3. Origins

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    In this series, comedian and physicist Ben Miller asks the CERN scientists what they hope to find. If the LHC is successful, it will explain the nature of the Universe around us in terms of a few simple ingredients and a few simple rules. But the Universe now was forged in a Big Bang where conditions were very different, and the rules were very different, and those early moments were crucial to determining how things turned out later. At the LHC they can recreate conditions as they were billionths of a second after the Big Bang, before atoms and nuclei existed. They can find out why matter and antimatter didn't mutually annihilate each other to leave behind a Universe of pure, brilliant light. And they can look into the very structure of space and time - the fabric of the Universe

  20. Big Bang Day: 5 Particles - 3. The Anti-particle

    SciTech Connect (OSTI)

    None

    2009-10-07T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 3. The Anti-particle. It appears to be the stuff of science fiction. Associated with every elementary particle is an antiparticle which has the same mass and opposite charge. Should the two meet and combine, the result is annihilation - and a flash of light. Thanks to mysterious processes that occurred after the Big Bang there are a vastly greater number of particles than anti-particles. So how could their elusive existence be proved? At CERN particle physicists are crashing together subatomic particles at incredibly high speeds to create antimatter, which they hope will finally reveal what happened at the precise moment of the Big Bang to create the repertoire of elementary particles and antiparticles in existence today.

  1. Supernova bangs as a tool to study big bang

    SciTech Connect (OSTI)

    Blinnikov, S. I., E-mail: Sergei.Blinnikov@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation)

    2012-09-15T23:59:59.000Z

    Supernovae and gamma-ray bursts are the most powerful explosions in observed Universe. This educational review tells about supernovae and their applications in cosmology. It is explained how to understand the production of light in the most luminous events with minimum required energy of explosion. These most luminous phenomena can serve as primary cosmological distance indicators. Comparing the observed distance dependence on red shift with theoretical models one can extract information on evolution of the Universe from Big Bang until our epoch.

  2. Nucleosynthesis Without a Computer

    E-Print Network [OSTI]

    V. Mukhanov

    2003-03-04T23:59:59.000Z

    I derive completely analytically the time evolution and final abundances of the light elements (up to Be-7) formed in the big-bang nucleosynthesis.This highlights an interesting physics taking place during the formation of light elements in the early universe.

  3. Anti-Proton Evolution in Little Bangs and Big Bang

    E-Print Network [OSTI]

    H. Schade; B. Kampfer

    2009-03-30T23:59:59.000Z

    The abundances of anti-protons and protons are considered within momentum-integrated Boltzmann equations describing Little Bangs, i.e., fireballs created in relativistic heavy-ion collisions. Despite of a large anti-proton annihilation cross section we find a small drop of the ratio of anti-protons to protons from 170 MeV (chemical freeze-out temperature) till 100 MeV (kinetic freeze-out temperature) for CERN-SPS and BNL-RHIC energies thus corroborating the solution of the previously exposed "ani-proton puzzle". In contrast, the Big Bang evolves so slowly that the anti-baryons are kept for a long time in equilibrium resulting in an exceedingly small fraction. The adiabatic path of cosmic matter in the phase diagram of strongly interacting matter is mapped out.

  4. The Decay of the Neutron or Beta Decay, the Big Bang, and the...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Decay of the Neutron or Beta Decay, the Big Bang, and the Left-Handed Universe Apr 03 2014 01:00 PM - 02:30 PM Geoffrey L. Greene Physics Division, ORNL Research Accelerator...

  5. Big Bang Day : Afternoon Play - Torchwood: Lost Souls

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Martha Jones, ex-time traveller and now working as a doctor for a UN task force, has been called to CERN where they're about to activate the Large Hadron Collider. Once activated, the Collider will fire beams of protons together recreating conditions a billionth of a second after the Big Bang - and potentially allowing the human race a greater insight into what the Universe is made of. But so much could go wrong - it could open a gateway to a parallel dimension, or create a black hole - and now voices from the past are calling out to people and scientists have started to disappear... Where have the missing scientists gone? What is the secret of the glowing man? What is lurking in the underground tunnel? And do the dead ever really stay dead? Lost Souls is a spin-off from the award-winning BBC Wales TV production Torchwood. It stars John Barrowman, Freema Agyeman, Eve Myles, Gareth David-Lloyd, Lucy Montgomery (of Titty Bang Bang) and Stephen Critchlow.

  6. Big Bang Day : Afternoon Play - Torchwood: Lost Souls

    SciTech Connect (OSTI)

    None

    2009-10-13T23:59:59.000Z

    Martha Jones, ex-time traveller and now working as a doctor for a UN task force, has been called to CERN where they're about to activate the Large Hadron Collider. Once activated, the Collider will fire beams of protons together recreating conditions a billionth of a second after the Big Bang - and potentially allowing the human race a greater insight into what the Universe is made of. But so much could go wrong - it could open a gateway to a parallel dimension, or create a black hole - and now voices from the past are calling out to people and scientists have started to disappear... Where have the missing scientists gone? What is the secret of the glowing man? What is lurking in the underground tunnel? And do the dead ever really stay dead? Lost Souls is a spin-off from the award-winning BBC Wales TV production Torchwood. It stars John Barrowman, Freema Agyeman, Eve Myles, Gareth David-Lloyd, Lucy Montgomery (of Titty Bang Bang) and Stephen Critchlow.

  7. From the Big Bang to the Higgs Boson in Less Than an Hour

    E-Print Network [OSTI]

    Fygenson, Deborah Kuchnir

    From the Big Bang to the Higgs Boson in Less Than an Hour Jeffrey D H Higgs boson Gauge bosons (force field quanta) Higgs boson and vacuum expectation value Strong) photon Z boson W bosons H Higgs boson Gauge bosons (force field quanta) Higgs boson and vacuum

  8. From the Big Bang to the Higgs Boson in Less Than an Hour

    E-Print Network [OSTI]

    Fygenson, Deborah Kuchnir

    From the Big Bang to the Higgs Boson in Less Than an Hour Jeffrey D neutrino Z0 W + W -g gluon (8) photon Z boson W bosons Quarks Leptons H Higgs boson Gauge bosons (force field quanta) Higgs boson and vacuum expectation value Strong force EM force Weak force #12;Par7cles

  9. Birth of Supermassive Black holes and Star Formation after the Big Bang

    E-Print Network [OSTI]

    A Paramashivam

    2013-01-01T23:59:59.000Z

    Modern observations of star formation in different galaxies contradicts with the current star formation theories. There are few questions and observations where current star formation theories were not able to explain well. This paper proposes an alternative theory of Star formation and birth of Supermassive Black holes after the Big Bang, which can answer the contradictions without violating the physics laws and fit perfectly well with the modern observations.

  10. Unveiling secret interactions among sterile neutrinos with big-bang nucleosynthesis

    E-Print Network [OSTI]

    Ninetta Saviano; Ofelia Pisanti; Gianpiero Mangano; Alessandro Mirizzi

    2014-11-15T23:59:59.000Z

    Short-baseline neutrino anomalies suggest the existence of low-mass ( m \\sim O(1)~eV) sterile neutrinos \

  11. Big-bang nucleosynthesis with a long-lived CHAMP including He4 spallation process

    E-Print Network [OSTI]

    Toshifumi Jittoh; Kazunori Kohri; Masafumi Koike; Joe Sato; Kenichi Sugai; Masato Yamanaka; Koichi Yazaki

    2012-09-10T23:59:59.000Z

    We propose helium-4 spallation processes induced by long-lived stau in supersymmetric standard models, and investigate an impact of the processes on light elements abundances. We show that, as long as the phase space of helium-4 spallation processes is open, they are more important than stau-catalyzed fusion and hence constrain the stau property. This talk is based on works (Jittoh et al., 2011).

  12. Quark mass variation constraints from Big Bang nucleosynthesis | SciTech

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOn AprilAElectronicCurvesSpeedingScientificof ScientificQ LA-UR- " "

  13. R+S^2 theories of gravity without big-bang singularity

    E-Print Network [OSTI]

    Jia-An Lu

    2015-02-10T23:59:59.000Z

    The R+S^2 theories of gravity, where S^2 denotes the quadratic torsion terms, are analyzed under three cases. In the first two cases, the matter fields are described by two different spin fluids which are not homogeneous and isotropic. In the third case, a homogeneous and isotropic torsion field is used. It is found that under all the three cases, the R+S^2 theories may avert the big-bang singularity of the Robertson--Walker universe, with three corresponding constraints on the parameters.

  14. CMB B-modes, spinorial space-time and Pre-Big Bang (II)

    E-Print Network [OSTI]

    Luis Gonzalez-Mestres

    2014-08-02T23:59:59.000Z

    The BICEP2 collaboration reported recently a B-mode polarization of the cosmic microwave background (CMB) radiation inconsistent with the null hypothesis at a significance of > 5 {\\sigma}. This result has been often interpreted as a signature of primordial gravitational waves from cosmic inflation, even if actually polarized dust emission may be at the origin of such a signal. Even assuming that part of this CMB B-mode polarization really corresponds to the early Universe dynamics, its interpretation in terms of inflation and primordial gravitational waves is not the only possible one. Alternative cosmologies such as pre-Big Bang patterns and the spinorial space-time (SST) we introduced in 1996-97 can naturally account for such CMB B-modes. In particular, the SST automatically generates a privileged space direction (PSD) whose existence may have been confirmed by Planck data. If such a PSD exists, it seems normal to infer that vector perturbations have been present in the early Universe leading to CMB B-modes in suitable cosmological patterns. Inflation would not be required to explain the BICEP2 result assuming it really contains a primordial signal. More generally, pre-Big Bang cosmologies can also generate gravitational waves in the early Universe without any need for cosmic inflation. We further discuss here possible alternatives to the inflationary interpretation of a primordial B-mode polarization of cosmic microwave background radiation.

  15. The Problem of Big Bang Matter vs. AntiMatter Symmetry

    E-Print Network [OSTI]

    Roger Ellman

    2011-11-07T23:59:59.000Z

    -The favored Big Bang concept is that the original symmetry was skewed, the universe now being all matter, all antimatter having annihilated. -The mechanism of matter/antimatter annihilation is analyzed. A total annihilation of original antimatter could not have occurred; the skewing is unnecessary; and the universe must contain equally both forms of matter. -Current detection of cosmic matter/antimatter annihilations is Gamma Ray Bursts [GRB's]. However, the conviction that the universe is now all matter with no antimatter has left that possibility rejected and uninvestigated and left standing the massive supernovae core collapse hypothesis for GRB's. -It has recently been reported that the rate of GRB's increases with red shift z for z = 0 to 4 as (1 + z)^1.5. The indication is that the rate increases significantly with time into the past at least back to z = 4 [and probably back to the Big Bang]. -That finding is inconsistent with the massive supernovae core collapse hypothesis for GRB's and supports GRB's being cosmic matter/antimatter annihilations.

  16. The Multiverse Origin of our Physics does without Strings, Big Bang, Inflation, or Parallel Universes

    E-Print Network [OSTI]

    Tom Gehrels

    2009-12-29T23:59:59.000Z

    Evolution needs long times and large numbers of samples or species. Our finely tuned physics can therefore not have evolved during the fast changes of a single Big-Bang universe, but the cosmological scales for time and for the number of universes in the multiverse satisfy that condition. Planck and Chandrasekhar equations show that multiverse. A variety of observations show the origin of our physics. The multiverse is being fed by the debris of its decaying universes, which is transported on the accelerated expansion. New universes originate from clouds of that debris, which is re-energized by the gravity at the center of the cloud when the proton density is reached. That epoch occurs much later than a Big Bang. It marks the beginning of our universe with a photon burst, which may have been observed by spacecraft as the radiation signature with a wider curvature than that of the cosmic background radiation. A test for black holes, published by Karl Schwarzschild in 1916, also confirms that beginning.

  17. Physicists believe that our universe began with a huge explosion about thirteen billion years ago, called the Big Bang.

    E-Print Network [OSTI]

    Kazama, Hokto

    the cooling period, after the Big Bang explosion, quarks and electrons were formed, followed by protons particles cannot be separated from the macroscopic system at large. RHIC is the first high energy of 20th century physics indicates, scientific progress has always been made by younger researchers

  18. The Big Bang, COBE, and the Relic Radiation of Creation (LBNL Science at the Theater)

    ScienceCinema (OSTI)

    Smoot, George

    2011-04-28T23:59:59.000Z

    Berkeley Lab's George Smoot won the 2006 Physics Nobel Prize, together with John Mather of NASA Goddard Space Flight Center, for "the discovery of the blackbody form and anisotropy of the cosmic microwave background radiation." The anisotropy showed as small variations in the map of the early universe. This research looks back into the infant universe and provides a better understanding of the origin of galaxies and stars. The cosmic background radiation is a tool to understand the structure and history of the universe and the structure of space-time. These observations have provided increased support for the big bang theory of the universe's origin. The Cosmic Background Explorer (COBE) NASA satellite, launched in 1989, carries instruments that measured various aspects of cosmic microwave background radiation, and produced the data for these compelling scientific results, which opened up a field that continues very actively today.

  19. "Soft bang" instead of "big bang": model of an inflationary universe without singularities and with eternal physical past time

    E-Print Network [OSTI]

    E. Rebhan

    2006-02-23T23:59:59.000Z

    The solution for an inflationary universe without singularities is derived from the Einstein-Lemaitre equations. The present state of the universe evolved from a steady state solution for a tiny, but classical micro-universe with large cosmological constant or large equivalent vacuum energy density and with an equal energy density of radiation and/or some kind of relativistic primordial matter in the infinite past. An instability of this state outside the quantum regime caused a "soft bang" by triggering an expansion that smoothly started with zero expansion rate, continuously increased, culminated in an exponentially inflating phase and ended through a phase transition, the further evolution being a Friedmann-Lemaitre evolution as in big bang models. As a necessary implication of the model the universe must be closed. All other parameters of the model are very similar to those of big bang models and comply with observational constraints.

  20. Nonperturbative dynamics of reheating after inflation: A review

    E-Print Network [OSTI]

    Amin, Mustafa A.

    Our understanding of the state of the universe between the end of inflation and big bang nucleosynthesis (BBN) is incomplete. The dynamics at the end of inflation are rich and a potential source of observational signatures. ...

  1. Dust production 680-850 million years after the Big Bang

    E-Print Network [OSTI]

    Micha?owski, Micha? J

    2015-01-01T23:59:59.000Z

    Dust plays an important role in our understanding of the Universe, but it is not obvious yet how the dust in the distant universe was formed. I derived the dust yields per asymptotic giant branch (AGB) star and per supernova (SN) required to explain dust masses of galaxies at z = 6.3-7.5 (680-850 million years after the Big Bang) for which dust emission has been detected (HFLS3 at z = 6.34, ULAS J1120+0641 at z = 7.085, and A1689-zD1 at z = 7.5), or unsuccessfully searched for. I found very high required yields, implying that AGB stars could not contribute substantially to dust production at these redshifts, and that SNe could explain these dust masses, but only if they do not destroy majority of the dust they form (which is unlikely given the upper limits on the SN dust yields derived for dust non-detected galaxies). This suggests that the grain growth in the interstellar medium is likely required at these early epochs.

  2. The Possibility of Curved Spacetime, Black Holes, and Big Bang is Less than One Billionth

    E-Print Network [OSTI]

    Jin He

    2007-10-20T23:59:59.000Z

    Gravity whose nature is fundamental to the understanding of solar system, galaxies and the structure and evolution of the Universe, is theorized by the assumption of curved spacetime, according to Einstein`s general theory of relativity (EGR). Particles move on curved spacetime along straight lines (geodesics). In the last year, I proposed the mirrored version of EGR, the flat-spacetime general relativity (FGR), in which particles move along curved lines on flat spacetime. This puts gravitational study back to the traditional Lagrangian formulation. In fact, all claimed accurate verification of general relativity is the verification of FGR, because people when confronting GR to observational data, calculate time, distance, or angle by directly using the coordinates in Schwarzschild solution or in post Newtonian formulation. For example, people calculate the angles by directly using the coordinate $\\phi$. However, only when spacetime is flat does there exists one coordinate system which has direct meaning of time, distance, angle, and vice verse. This is the famous Riemann theorem. Therefore, the more claims are made that classical tests of general relativity fit data with great accuracy, the more falsified is the curved-spacetime assumption. People made three such specious claims to EGR as collected in the present paper. However, FGR predicts observationally verified results consistently for solar system, galaxies, and the universe on the whole. I show that the possibility of curved spacetime, black holes, and big bang is less than one billionth. An experiment is proposed whose results will completely decide the fate of curved spacetime assumption. with the original article `Einstein`s Geometrization vs. Holonomic Cancellation of Gravity via Spatial Coordinate-rescale` attached.

  3. Origin of matter and space-time in the big bang

    SciTech Connect (OSTI)

    Mathews, G. J. [University of Notre Dame, Center for Astrophysics/JINA, Notre Dame, IN 46556, USA and Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Kajino, T. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamazaki, D. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791, Korea and Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of)

    2014-05-02T23:59:59.000Z

    We review the case for and against a bulk cosmic motion resulting from the quantum entanglement of our universe with the multiverse beyond our horizon. Within the current theory for the selection of the initial state of the universe from the landscape multiverse there is a generic prediction that pre-inflation quantum entanglement with other universes should give rise to a cosmic bulk flow with a correlation length of order horizon size and a velocity field relative to the expansion frame of the universe. Indeed, the parameters of this motion are are tightly constrained. A robust prediction can be deduced indicating that there should be an overall motion of of about 800 km/s relative to the background space time as defined by the cosmic microwave background (CMB). This talk will summarize the underlying theoretical motivation for this hypothesis. Of course our motion relative to the background space time (CMB dipole) has been known for decades and is generally attributed to the gravitational pull of the local super cluster. However, this cosmic peculiar velocity field has been recently deduced out to very large distances well beyond that of the local super cluster by using X-ray galaxy clusters as tracers of matter motion. This is achieved via the kinematic component of the Sunyaev-Zeldovich (KSZ) effect produced by Compton scattering of cosmic microwave background photons from the local hot intracluster gas. As such, this method measures peculiar velocity directly in the frame of the cluster. Similar attempts by our group and others have attempted to independently assess this bulk flow via Type la supernova redshifts. In this talk we will review the observation case for and against the existence of this bulk flow based upon the observations and predictions of the theory. If this interpretation is correct it has profound implications in that we may be observing for the first time both the physics that occurred before the big bang and the existence of the multiverse beyond our horizon.

  4. Big Bang Day : Today

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Andrew Marr will be reporting live from the CERN control room for the Today programme, with correspondent Tom Feilden. (Wednesday 10th September, 6.00-9.00am )

  5. Constraining spacetime noncommutativity with primordial nucleosynthesis

    SciTech Connect (OSTI)

    Horvat, Raul [Physics Division, Rudjer Boskovic Institute, Zagreb (Croatia); Trampetic, Josip [Theoretical Physics Division, Rudjer Boskovic Institute, Zagreb (Croatia)

    2009-04-15T23:59:59.000Z

    We discuss a constraint on the scale {lambda}{sub NC} of noncommutative (NC) gauge field theory arising from consideration of the big bang nucleosynthesis of light elements. The propagation of neutrinos in the NC background described by an antisymmetric tensor {theta}{sup {mu}}{sup {nu}} does result in a tree-level vectorlike coupling to photons in a generation-independent manner, raising thus a possibility to have an appreciable contribution of three light right-handed (RH) fields to the energy density of the Universe at nucleosynthesis time. Considering elastic scattering processes of the RH neutrinos off charged plasma constituents at a given cosmological epoch, we obtain for a conservative limit on an effective number of additional doublet neutrinos {delta}N{sub {nu}}=1, a bound {lambda}{sub NC} > or approx. 3 TeV. With a more stringent requirement, {delta}N{sub {nu}} < or approx. 0.2, the bound is considerably improved, {lambda}{sub NC} > or approx. 10{sup 3} TeV. For our bounds the {theta} expansion of the NC action stays always meaningful, since the decoupling temperature of the RH species is perseveringly much less than the inferred bound for the scale of noncommutativity.

  6. The DARPA WNaN Network Architecture Raytheon BBN Technologies

    E-Print Network [OSTI]

    Ramanathan, Ram

    The DARPA WNaN Network Architecture Jason Redi Raytheon BBN Technologies Cambridge, MA redi@bbn.com Ram Ramanathan Raytheon BBN Technologies Cambridge, MA ramanath@bbn.com Abstract-- The warfighter its goal. WNaN uses networking software from Raytheon BBN Technologies, and radio hardware plus

  7. Primordial Nucleosynthesis Constraints on Z' Properties

    E-Print Network [OSTI]

    Vernon Barger; Paul Langacker; Hye-Sung Lee

    2003-02-13T23:59:59.000Z

    In models involving new TeV-scale Z' gauge bosons, the new U(1)' symmetry often prevents the generation of Majorana masses needed for a conventional neutrino seesaw, leading to three superweakly interacting ``right-handed'' neutrinos nu_R, the Dirac partners of the ordinary neutrinos. These can be produced prior to big bang nucleosynthesis by the Z' interactions, leading to a faster expansion rate and too much ^4He. We quantify the constraints on the Z' properties from nucleosynthesis for Z' couplings motivated by a class of E_6 models parametrized by an angle theta_E6. The rate for the annihilation of three approximately massless right-handed neutrinos into other particle pairs through the Z' channel is calculated. The decoupling temperature, which is higher than that of ordinary left-handed neutrinos due to the large Z' mass, is evaluated, and the equivalent number of new doublet neutrinos Delta N_nu is obtained numerically as a function of the Z' mass and couplings for a variety of assumptions concerning the Z-Z' mixing angle and the quark-hadron transition temperature T_c. Except near the values of theta_E6 for which the Z' decouples from the right-handed neutrinos, the Z' mass and mixing constraints from nucleosynthesis are much more stringent than the existing laboratory limits from searches for direct production or from precision electroweak data, and are comparable to the ranges that may ultimately be probed at proposed colliders. For the case T_c = 150 MeV with the theoretically favored range of Z-Z' mixings, Delta N_nu 4.3 TeV for any value of theta_E6. Larger mixing or larger T_c often lead to unacceptably large Delta N_nu except near the nu_R decoupling limit.

  8. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

    Christian Iliadis; Richard Longland; Alain Coc; F. X. Timmes; Art E. Champagne

    2014-09-19T23:59:59.000Z

    Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and gamma-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples are given for applications to s-process neutron sources, core-collapse supernovae, classical novae, and big bang nucleosynthesis.

  9. Neutrino Physics and the Primordial Elemental Abundances

    E-Print Network [OSTI]

    Christian Y. Cardall; George M. Fuller

    1997-01-31T23:59:59.000Z

    Limits can be placed on nonstandard neutrino physics when big bang nucleosynthesis (BBN) calculations employing standard neutrino physics agree with the observationally inferred primordial abundances of deuterium (D), $^3$He, $^4$He, and $^7$Li. These constraints depend most sensitively on the abundances of D and $^4$He. New observational determinations of the primordial D and/or $^4$He abundances could force revisions in BBN constraints on nonstandard neutrino physics.

  10. Neutrino Oscillations and the Early Universe

    E-Print Network [OSTI]

    D. P. Kirilova

    2003-12-21T23:59:59.000Z

    The observational and theoretical status of neutrino oscillations in connection with solar and atmospheric neutrino anomalies is presented in brief. The effect of neutrino oscillations on the early Universe evolution is discussed in detail. A short review is given of the standard Big Bang Nucleosynthesis and the influence of resonant and nonresonant neutrino oscillations on active neutrinos and on primordial nucleosynthesis of He-4. BBN cosmological constraints on neutrino oscillation parameters are discussed.

  11. 38The Big Bang -Cosmic Expansion According to Big Bang

    E-Print Network [OSTI]

    special cases A) The Inflationary Universe case where U >> 1 and B) the matter-dominated universe case

  12. Big Bang Day: Engineering Solutions

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    CERN's Large Hadron Collider is the most complicated scientific apparatus ever built. Many of the technologies it uses hadn't even been invented when scientists started building it. Adam Hart-Davis discovers what it takes to build the world's most intricate discovery machine.

  13. Big Bang Day : Physics Rocks

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Is particle physics the new rock 'n' roll? The fundamental questions about the nature of the universe that particle physics hopes to answer have attracted the attention of some very high profile and unusual fans. Alan Alda, Ben Miller, Eddie Izzard, Dara O'Briain and John Barrowman all have interests in this branch of physics. Brian Cox - CERN physicist, and former member of 90's band D:Ream, tracks down some very well known celebrity enthusiasts and takes a light-hearted look at why this subject can appeal to all of us.

  14. A New Theory of Cosmology That Preserves the Generally Recognized Symmetries of Cosmos, Explains the Origin of the Energy for Matter Field, but Excludes the Existence of the Big Bang

    E-Print Network [OSTI]

    Fang-Pei Chen

    2006-05-12T23:59:59.000Z

    While the generally recognized symmetries of cosmos are preserved, conservation laws for gravitational system are reconsidered and the Lagrangian density of pure gravitational field is revised. From these considerations, some of the theoretical foundations of the current cosmology are extended or revised, and a new theory of cosmology is established. This new theory leads to the following distinct properties of cosmos: the energy of matter field might originate from the gravitational field; the big bang might not have occurred; the fields of the dark energy and some parts of the dark matter would not be matter fields but might be gravitational fields, they would only interact with gravitational force but could not interact with other forces. These distinct properties can be tested by future experiments and observations.

  15. BBN Technical Memorandum No. TM-2023 Ultra Low Latency MANETs

    E-Print Network [OSTI]

    Ramanathan, Ram

    communication ranges foretell MANETs with very large diameters. Indeed, an architecture where dense low-cost: ramanath@bbn.com Fabrice Tchakountio Mobile Networking Systems Department BBN Technologies Cambridge, MA a MANET to a large number of hops. MANETs are trending toward larger numbers of nodes due to increasing

  16. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect (OSTI)

    Claudia, Travaglio [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Torino; Hix, William Raphael [ORNL

    2013-01-01T23:59:59.000Z

    We review our understanding of the nucleosynthesis that occurs in thermonuclear supernovae and their contribution to Galactic Chemical evolution. We discuss the prospects to improve the modeling of the nucleosynthesis within simulations of these events.

  17. Large neutrino asymmetries from neutrino oscillations

    E-Print Network [OSTI]

    R. Foot; M. J. Thomson; R. R. Volkas

    1995-09-19T23:59:59.000Z

    We re-examine neutrino oscillations in the early universe. Contrary to previous studies, we show that large neutrino asymmetries can arise due to oscillations between ordinary neutrinos and sterile neutrinos. This means that the Big Bang Nucleosynthesis (BBN) bounds on the mass and mixing of ordinary neutrinos with sterile neutrinos can be evaded. Also, it is possible that the neutrino asymmetries can be large (i.e. $\\stackrel{>}{\\sim} 10\\%$), and hence have a significant effect on BBN through nuclear reaction rates.

  18. Precision Cosmology and the Density of Baryons in the Universe

    E-Print Network [OSTI]

    M. Kaplinghat; M. S. Turner

    2000-11-14T23:59:59.000Z

    Big-bang Nucleosynthesis (BBN) and Cosmic Microwave Background (CMB) anisotropy measurements give independent, accurate measurements of the baryon density and can test the framework of the standard cosmology. Early CMB data are consistent with the longstanding conclusion from BBN that baryons constitute a small fraction of matter in the Universe, but may indicate a slightly higher value for the baryon density. We clarify precisely what the two methods determine, and point out that differing values for the baryon density can indicate either an inconsistency or physics beyond the standard models of cosmology and particle physics. We discuss other signatures of the new physics in CMB anisotropy.

  19. BBN And The CMB Constrain Neutrino Coupled Light WIMPs

    E-Print Network [OSTI]

    Nollett, Kenneth M

    2014-01-01T23:59:59.000Z

    (abridged) In the presence of a light WIMP (mass m_chi 35 MeV, equivalent to no light WIMP at all. Without any light WIMP, BBN alone prefers Delta N_nu = 0.50 +- 0.23, favoring neither Delta N_nu = 0, nor a fully thermalized sterile neutrino (Delta N_nu = 1). This result is consistent with the CMB constraint, N_eff = 3.30 +- 0.27, limiting "new physics" between BBN and recombination. Combining BBN and CMB data gives Delta N_nu = 0.35 +- 0.16 and N_eff = 3.40 +- 0.16; while BBN and the CMB combined require Delta N_nu > 0 at ~98% confidence, they disfavor Delta N_nu > 1 at > 99% confidence. Allowing a neutrino-coupled light WIMP extends the allowed range slightly downward for Delta N_nu and slightly upward for N_eff simultaneously, leaving best-fit values unchanged.

  20. Les preuves observationnelles du Big Bang

    E-Print Network [OSTI]

    Citi, Sandra

    'astronomie moderne: · Nicolas Copernic (1473 ­ 1543) met le Soleil et non plus la Terre au centre du monde · Tycho

  1. Big Bang: astrophysical fantasy fantastic fact?

    E-Print Network [OSTI]

    Korn, Andreas

    ) are in thephoton emission) are in the 100100 KK rangerange (Nobel price 2006).(Nobel price 2006). #12;BOOMERan ratios of hydroge,of hydroge, helium and lithiumhelium and lithium as a function of theas a function: helium in different cosmic sourcescosmic sources 1980s:1980s: lithium in old starslithium in old stars

  2. Big-Bang Cosmology Hitoshi Murayama

    E-Print Network [OSTI]

    Murayama, Hitoshi

    and Homogeneity fi maximally symmetric space ­ Flat Euclidean space R3 ­ Closed three-sphere S3=SO(4)/SO(3) ­ Open · Equation that governs expansion of the Universe ­ k=­1 (closed), k=1 (open), k=0 (flat) ­ energy density r;Polarization · Compton scattering polarizes the photon in the polarization plane Ei E j - 1 2 dij r E2 µ

  3. LHC, le Big Bang en éprouvette

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    Notre compréhension de l?Univers est en train de changer? Bar des Sciences - Tout public Débat modéré par Marie-Odile Montchicourt, journaliste de France Info. Evenement en vidéoconférence entre le Globe de la science et de l?innovation, le bar le Baloard de Montpellier et la Maison des Métallos à Paris. Intervenants au CERN : Philippe Charpentier et Daniel Froideveaux, physiciens au CERN. Intervenants à Paris : Vincent Bontemps, philosophe et chercheur au CEA ; Jacques Arnould, philosophe, historien des sciences et théologien, Jean-Jacques Beineix, réalisateur, producteur, scénariste de cinéma. Intervenants à Montpellier (LPTA) : André Neveu, physicien théoricien et directeur de recherche au CNRS ; Gilbert Moultaka, physicien théoricien et chargé de recherche au CNRS. Partenariat : CERN, CEA, IN2P3, Université MPL2 (LPTA) Dans le cadre de la Fête de la science 2008

  4. A different Big Bang theory: Los Alamos

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del(ANL-IN-03-032) -Less isNFebruaryOctober 2,generation high-performance

  5. Non-Extensive Statistics, New Solution to the Cosmological Lithium Problem

    E-Print Network [OSTI]

    J. J. He; S. Q. Hou; A. Parikh; D. Kahl; C. A. Bertulani; other collaborators

    2014-12-22T23:59:59.000Z

    In the primordial Big Bang nucleosynthesis (BBN), only the lightest nuclides (D, $^3$He, $^4$He, and $^7$Li) were synthesized in appreciable quantities, and these relics provide us a unique window on the early universe. Currently, BBN simulations give acceptable agreement between theoretical and observed abundances of D and $^4$He, but it is still difficult to reconcile the predicted $^7$Li abundance with the observation for the Galactic halo stars. The BBN model overestimates the primordial $^7$Li abundance by about a factor of three, so called the cosmological lithium problem, a long-lasting pending issue in BBN. Great efforts have been paid in the past decades, however, the conventional nuclear physics seems unable to resolve such problem. It is well-known that the classical Maxwell-Boltzmann (MB) velocity distribution has been usually assumed for nuclei in the Big-Bang plasma. In this work, we have thoroughly investigated the impact of non-extensive Tsallis statistics (deviating from the MB) on thermonuclear reaction rates involved in standard models of BBN. It shows that the predicted primordial abundances of D, $^4$He, and $^7$Li agree very well with those observed ones by introducing a non-extensive parameter $q$. It is discovered that the velocities of nuclei in a hot Big-Bang plasma indeed violate the classical Maxwell-Boltzmann (MB) distribution in a very small deviation of about 6.3--8.2%. Thus, we have for the first time found a new solution to the cosmological lithium problem without introducing any mysterious theories. Furthermore, the implications of non-extensive statistics in other exotic high-temperature and density astrophysical environments should be explored, which might offer new insight into the nucleosynthesis of heavy elements.

  6. Primordial Helium And the Cosmic Background Radiation

    E-Print Network [OSTI]

    Gary Steigman

    2010-04-29T23:59:59.000Z

    The products of primordial nucleosynthesis and the cosmic microwave background (CMB) photons are relics from the early evolution of the Universe whose observations probe the standard model of cosmology and provide windows on new physics beyond the standard models of cosmology and of particle physics. In the standard, hot big bang cosmology, long before any stars have formed a significant fraction (~25%) of the baryonic mass in the Universe should be in the form of helium-4 nuclei. Since current 4He observations are restricted to low redshift regions where stellar nucleosynthesis has occurred, observations of high redshift, prestellar 4He would constitute a fundamental test of the hot, big bang cosmology. At recombination, long after big bang nucleosynthesis (BBN) has ended, the temperature anisotropy spectrum imprinted on the CMB depends on the 4He abundance through its connection to the electron density and the effect of the electron density on Silk damping. Since the relic abundance of 4He is relatively insensitive to the universal density of baryons, but is sensitive to a non-standard, early Universe expansion rate, the primordial mass fraction of 4He, Yp, offers a test of the consistency of the standard models of BBN and the CMB and, provides constraints on non-standard physics. Here, the WMAP seven year data (supplemented by other CMB experiments), which lead to an indirect determination of Yp at high redshift, are compared to the BBN predictions and to the independent, direct observations of 4He in low redshift, extragalactic HII regions. At present, given the very large uncertainties in the CMB-determined primordial 4He abundance (as well as for the helium abundances inferred from H II region observations), any differences between the BBN predictions and the CMB observations are small, at a level < 1.5 sigma.

  7. Explosive Nucleosynthesis: Prospects

    E-Print Network [OSTI]

    David Arnett

    1999-08-16T23:59:59.000Z

    Explosive nucleosynthesis is a combination of the nuclear physics of thermonuclear reactions, and the hydrodynamics of the plasma in which the reactions occur. It depends upon the initial conditions---the stellar evolution up to the explosive instability, and the nature of the explosion mechanism. Some key issues for explosive nucleosynthesis are the interaction of burning with hydrodynamics, the degree of microscopic mixing in convective zones, and the breaking of spherical symmetry by convection and rotation. Recent experiments on high intensity lasers provides new opportunities for laboratory testing of astrophysical hydrodynamic codes. Implications of SN1987A, SN1998bw (GRB980425?), and eta Carina are discussed, as well as the formation of black holes or neutron stars.

  8. Primordial nucleosynthesis and neutrino physics

    E-Print Network [OSTI]

    Smith, Christel Johanna

    2009-01-01T23:59:59.000Z

    A Brief History of and Introduction to Neutrino Physics . 13Nucleosynthesis and Neutrino Physics A dissertationdensity depend on new neutrino physics in di?erent ways. In

  9. A loophole to the universal photon spectrum in electromagnetic cascades: application to the "cosmological lithium problem"

    E-Print Network [OSTI]

    Poulin, Vivian

    2015-01-01T23:59:59.000Z

    The standard theory of electromagnetic cascades onto a photon background predicts a quasi-universal shape for the resulting non-thermal photon spectrum. This has been applied to very disparate fields, including non-thermal big bang nucleosynthesis (BBN). However, once the energy of the injected photons falls below the pair-production threshold the spectral shape is very different, a fact that has been overlooked in past literature. This loophole may have important phenomenological consequences, since it generically alters the BBN bounds on non-thermal relics: for instance it allows to re-open the possibility of purely electromagnetic solutions to the so-called "cosmological lithium problem", which were thought to be excluded by other cosmological constraints. We show this with a proof-of-principle example and a simple particle physics model, compared with previous literature.

  10. A loophole to the universal photon spectrum in electromagnetic cascades: application to the "cosmological lithium problem"

    E-Print Network [OSTI]

    Vivian Poulin; Pasquale D. Serpico

    2015-03-04T23:59:59.000Z

    The standard theory of electromagnetic cascades onto a photon background predicts a quasi-universal shape for the resulting non-thermal photon spectrum. This has been applied to very disparate fields, including non-thermal big bang nucleosynthesis (BBN). However, once the energy of the injected photons falls below the pair-production threshold the spectral shape is very different, a fact that has been overlooked in past literature. This loophole may have important phenomenological consequences, since it generically alters the BBN bounds on non-thermal relics: for instance it allows to re-open the possibility of purely electromagnetic solutions to the so-called "cosmological lithium problem", which were thought to be excluded by other cosmological constraints. We show this with a proof-of-principle example and a simple particle physics model, compared with previous literature.

  11. Nucleosynthesis in Type II Supernovae

    E-Print Network [OSTI]

    K. Nomoto; M. Hashimoto; T. Tsujimoto; F. -K. Thielemann; N. Kishimoto; Y. Kubo

    1997-06-03T23:59:59.000Z

    Presupernova evolution and explosive nucleosynthesis in massive stars for main-sequence masses from 13 $M_\\odot$ to 70 $M_\\odot$ are calculated. We examine the dependence of the supernova yields on the stellar mass, $^{12}C(\\alpha, \\gamma) ^{16}O}$ rate, and explosion energy. The supernova yields integrated over the initial mass function are compared with the solar abundances.

  12. Big Bang Day: The Making of CERN (Episode 2)

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    A two-part history of the CERN project. Quentin Cooper explores the fifty-year history of CERN, the European particle physics laboratory in Switzerland.

  13. Big Bang Day: The Making of CERN (Episode 1)

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    A two-part history of the CERN project. Quentin Cooper explores the fifty-year history of CERN, the European particle physics laboratory in Switzerland. The institution was created to bring scientists together after WW2 .......

  14. Big Bang Day: 5 Particles - 5. The Next Particle

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 5. The Next Particle The "sparticle" - a super symmetric partner to all the known particles could be the answer to uniting all the known particles and their interactions under one grand theoretical pattern of activity. But how do researchers know where to look for such phenomena and how do they know if they find them? Simon Singh reviews the next particle that physicists would like to find if the current particle theories are to ring true.

  15. Big Bang Day: 5 Particles - 4. The Neutrino

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". It's the most populous particle in the universe. Millions of these subatomic particles are passing through each one of us. With no charge and virtually no mass they can penetrate vast thicknesses of matter without any interaction - indeed the sun emits huge numbers that pass through earth at the speed of light. Neutrinos are similar to the more familiar electron, with one crucial difference: neutrinos do not carry electric charge. As a result they're extremely difficult to detect . But like HG Wells' invisible man they can give themselves away by bumping into things at high energy and detectors hidden in mines are exploiting this to observe these rare interactions.

  16. Gravity waves generated by sounds from Big Bang phase transitions

    E-Print Network [OSTI]

    Kalaydzhyan, Tigran

    2014-01-01T23:59:59.000Z

    Inhomogeneities associated with the cosmological QCD and electroweak phase transitions produce hydrodynamical perturbations, longitudinal sounds and rotations. It has been demonstrated numerically by Hindmarsh et al. that the sounds produce gravity waves (GW), and that this process does continue well after the phase transition is over. We further introduce a long period of the so-called inverse acoustic cascade, between the UV momentum scale at which the sound is originally produced and the IR scale at which GW is generated. It can be described by the Boltzmann equation, possessing stationary power and self-similar time-dependent solutions. If the sound dispersion law allows one-to-two sound decays, the exponent of the power solution is large and a strong amplification of the sound amplitude (limited only by the total energy) takes place. Alternative scenario dominated by sound scattering leads to smaller indices and much smaller IR sound amplitude. We also point out that two on shell phonons can produce a gr...

  17. Gravity waves generated by sounds from Big Bang phase transitions

    E-Print Network [OSTI]

    Tigran Kalaydzhyan; Edward Shuryak

    2015-01-14T23:59:59.000Z

    Inhomogeneities associated with the cosmological QCD and electroweak phase transitions produce hydrodynamical perturbations, longitudinal sounds and rotations. It has been demonstrated by Hindmarsh et al. that the sounds produce gravity waves (GW) well after the phase transition is over. We further argue, that, under certain conditions, an inverse acoustic cascade may occur and move sound perturbations from the (UV) momentum scale at which the sound is originally produced to much smaller (IR) momenta. Weak turbulence regime of this cascade is studied via Boltzmann equation, possessing stationary power and time-dependent self-similar solutions. We suggest certain indices for strong turbulence regime as well, into which the cascade eventually proceeds. Finally, we point out that two on shell sound waves can produce one on-shell gravity wave, and evaluate the rate of the process using standard sound loop diagram.

  18. On the Electrodynamics of the Big Bang Universe

    E-Print Network [OSTI]

    Howard D. Greyber

    2005-09-08T23:59:59.000Z

    Applying the known physics of plasmas to the evolution of galaxies and quasars in the Early Universe, a unique "Strong" Magnetic Field Modsl (SMF) was created that explains the origin of a very large-scale primordial magnetic field in each Supercluster and the observed large-scale structure of galaxies. This physical model, involving both gravitation and cosmical magnetism, explains the existence of significant magnetic fields in galaxies. An intense highly relativistic gravitationally bound current loop (Storage Ring) is formed by gravitational collapse explaining the nature of the AGN/Quasar Central Engine, galactic structure and radio, optical and X-ray jets.

  19. Echo of the Big Bang Anisotropies in the

    E-Print Network [OSTI]

    Weijgaert, Rien van de

    : Some Facts 7) CMB highly (impressively) Isotropic: - in each direction on the sky the radiation has Microwave Radiometer Cosmic Microwave Background #12;7/1/2009 6 Spectrum Blackbody Radiation John Mather: - photon energy 4) Energy Density Radiation evolves: Cosmic Radiation 44 )1()( ztarad 3 )(tanrad 1 )(tarad

  20. Big Bang Day: The Making of CERN (Episode 1)

    SciTech Connect (OSTI)

    None

    2009-10-06T23:59:59.000Z

    A two-part history of the CERN project. Quentin Cooper explores the fifty-year history of CERN, the European particle physics laboratory in Switzerland. The institution was created to bring scientists together after WW2 .......

  1. Schrodinger/Milne Big Bang. Creating a 'Universe of Threeness'

    E-Print Network [OSTI]

    Chew, Geoffrey F

    2015-01-01T23:59:59.000Z

    A Schrodinger-evolving forward/lightcone-interior 'Milne' universe ('SMU') is governed by 'entered-Lorentz' (CL) symmetry/that of a 9 parameter Lie group with a 6 parameter SL(2,c) 'exterior' and a 3 parameter 'quality space' center. 'Reality' resides in current densities of electric charge and energy momentum/the Dalembertian of an SMU ray specified classical retarded Lorentz tensor field with 22 electromagnetic and 32 gravitational components.

  2. Schrodinger/Milne Big Bang. Creating a 'Universe of Threeness'

    E-Print Network [OSTI]

    Geoffrey F. Chew

    2014-12-29T23:59:59.000Z

    A Schrodinger-evolving forward/lightcone-interior 'Milne' universe ('SMU') is governed by 'entered-Lorentz' (CL) symmetry/that of a 9 parameter Lie group with a 6 parameter SL(2,c) 'exterior' and a 3 parameter 'quality space' center. 'Reality' resides in current densities of electric charge and energy momentum/the Dalembertian of an SMU ray specified classical retarded Lorentz tensor field with 22 electromagnetic and 32 gravitational components.

  3. Big Bang Day: 5 Particles - 1. The Electron

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 1. The Electron Just over a century ago, British physicist J.J. Thompson experimenting with electric currents and charged particles inside empty glass tubes, showed that atoms are divisible into indivisible elementary particles. But how could atoms be built up of these so called "corpuscles"? An exciting 30 year race ensued, to grasp the planetary model of the atom with its orbiting electrons, and the view inside the atom was born. Whilst the number of electrons around the nucleus of an atom determines their the chemistry of all elements, the power of electrons themselves have been harnessed for everyday use: electron beams for welding,cathode ray tubes and radiation therapy.

  4. Big Bang Day : The Great Big Particle Adventure - 1. Atom

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    In this series, comedian and physicist Ben Miller asks the CERN scientists what they hope to find. The notion of atoms dates back to Greek philosophers who sought a natural mechanical explanation of the Universe, as opposed to a divine one. The existence what we call chemical atoms, the constituents of all we see around us, wasn't proved until a hundred years ago, but almost simultaneously it was realised these weren't the indivisible constituents the Greeks envisaged. Much of the story of physics since then has been the ever-deeper probing of matter until, at the end of the 20th century, a complete list of fundamental ingredients had been identified, apart from one, the much discussed Higgs particle. In this programme, Ben finds out why this last particle is so pivotal, not just to atomic theory, but to our very existence - and how hopeful the scientists are of proving its existence.

  5. 3. Classical problems of the Standard Big Bang Model

    E-Print Network [OSTI]

    Aretxaga, Itziar

    and inflation stops. There are many variants of inflation. · Universe in the state of false vacuum · energy of Universe dominated by vacuum energy · Universe expands exponentially · In some models, when it transits to true vacuum matter/antimatter is created and inflation ends. #12;

  6. PPPL, Princeton launch hunt for Big Bang particles offering clues...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Universe Massive Neutrino Yield." Ptolemy was an ancient Greek astronomer who lived in Egypt during the first century. Darkest, coldest conditions achievable The task calls for...

  7. Big Bang Day: 5 Particles - 2. The Quark

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 2. The Quark "Three Quarks for Master Mark! Sure he hasn't got much of a bark." James Joyce's Finnegans Wake left its mark on modern physics when physicist Murray Gell Mann proposed this name for a group of hypothetical subatomic particles that were revealed in 1960 as the fundamental units of matter. Basic particles it seems are made up of even more basic units called quarks that make up 99.9% of visible material in the universe.. But why do we know so little about them? Quarks have never been seen as free particles but instead, inextricably bound together by the Strong Force that in turn holds the atomic nucleus together. This is the hardest of Nature's fundamental forces to crack, but recent theoretical advances, mean that the properties of the quark are at last being revealed.

  8. John C. Mather, the Big Bang, and the COBE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your Home as Ready for(SC) Jetting intoJohn 'Skip'B.

  9. A different Big Bang theory: Los Alamos unveils explosives detection

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItemResearch >InternshipDepartmentNeutrino-Induced Charged-CurrentN N U

  10. What Was There Before the Big Bang? | GE Global Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps1DOETHEWeeklyTRUDoes aAdministration ToWhat

  11. Big Bang or Big Bounce? | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWP TWPAlumniComplexMaterial Science | StanfordBidding

  12. Nucleosynthesis in Early Neutrino Driven Winds

    SciTech Connect (OSTI)

    Hoffman, R; Fisker, J; Pruet, J; Woosley, S; Janka, H; Buras, R

    2008-01-09T23:59:59.000Z

    Two recent issues related to nucleosynthesis in early proton-rich neutrino winds are investigated. In the first part we investigate the effect of nuclear physics uncertainties on the synthesis of {sup 92}Mo and {sup 94}Mo. Based on recent experimental results, we find that the proton rich winds of the model investigated here can not be the only source of the solar abundance of {sup 92}Mo and {sup 94}Mo. In the second part we investigate the nucleosynthesis from neutron rich bubbles and show that they do not contribute to the nucleosynthesis integrated over both neutron and proton-rich bubbles and proton-rich winds.

  13. High energy cosmic rays experiments inspired by noncommutative quantum field theory

    E-Print Network [OSTI]

    Josip Trampetic

    2012-10-19T23:59:59.000Z

    Phenomenological analysis of the covariant theta-exact noncommutative (NC) gauge field theory (GFT), inspired by high energy cosmic rays experiments, is performed in the framework of the inelastic neutrino-nucleon scatterings, plasmon and $Z$-boson decays into neutrino pair, the Big Bang Nucleosynthesis (BBN) and the Reheating Phase After Inflation (RPAI), respectively. Next we have have found neutrino two-point function and shows a closed form decoupling of the hard ultraviolet (UV) divergent term from softened ultraviolet/infrared (UV/IR) mixing term and from the finite terms as well. For a certain choice of the noncommutative parameter theta which preserves unitarity, problematic UV divergent and UV/IR mixing terms vanish. Non-perturbative modifications of the neutrino dispersion relations are assymptotically independent of the scale of noncommutativity in both the low and high energy limits and may allow superluminal propagation.

  14. Sterile Neutrinos with Secret Interactions - Lasting Friendship with Cosmology

    E-Print Network [OSTI]

    Chu, Xiaoyong; Kopp, Joachim

    2015-01-01T23:59:59.000Z

    Sterile neutrinos with mass ~1 eV and order 10% mixing with active neutrinos have been proposed as a solution to anomalies in neutrino oscillation data, but are tightly constrained by cosmological limits. It was recently shown that these constraints are avoided if sterile neutrinos couple to a new MeV-scale gauge boson A'. However, even this scenario is restricted by structure formation constraints when A'-mediated collisional processes lead to efficient active-to-sterile neutrino conversion after neutrinos have decoupled. In view of this, we reevaluate in this paper the viability of sterile neutrinos with such "secret" interactions. We carefully dissect their evolution in the early Universe, including the various production channels and the expected modifications to large scale structure formation. We argue that there are two regions in parameter space - one at very small A' coupling, one at relatively large A' coupling - where all constraints from big bang nucleosynthesis (BBN), cosmic microwave background ...

  15. Precise Nucleosynthesis Limits on Neutrino Masses

    E-Print Network [OSTI]

    Kimmo Kainulainen

    1996-08-02T23:59:59.000Z

    A computation of nucleosynthesis bounds on the masses of long-lived Dirac and Majorana neutrinos is reviewed. In particular an explicit treatment of the ``differential heating'' of the $\

  16. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

    Sieverding, A; Langanke, K; Martínez-Pinedo, G; Heger, A

    2015-01-01T23:59:59.000Z

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z < 76 $ and ii) by considering modern supernova neutrino spectra which have substantially lower average energies compared to those previously adopted in neutrino nucleosynthesis studies. We confirm the production of $^7$Li, $^{11}$B, $^{138}$La, and $^{180}$Ta by neutrino nucleosynthesis, albeit at slightly smaller abundances due to the changed neutrino spectra. We find that for stars with a mass smaller than 20 M$_\\odot$, $^{19}$F is produced mainly by explosive nucleosynthesis while for higher mass stars it is produced by the $\

  17. Nucleosynthesis in O-Ne-Mg Supernovae

    SciTech Connect (OSTI)

    Hoffman, R D; Janka, H; Muller, B

    2007-12-18T23:59:59.000Z

    We have studied detailed nucleosynthesis in the shocked surface layers of an oxygen-neon-magnesium core collapse supernova with an eye to determining whether the conditions are suitable for r-process nucleosynthesis. We find no such conditions in an unmodified model, but do find overproduction of N=50 nuclei (previously seen in early neutron-rich neutrino winds) in amounts that, if ejected, would pose serious problems for Galactic chemical evolution.

  18. Rep. Prog. Phys. 62 (1999) 395464. Printed in the UK PII: S0034-4885(99)74702-0 Nuclear astrophysics

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    decays via strong interaction 423 5. Thermonuclear reactions in non-explosive events 424 5.1. Energy and concomitant nucleosynthesis 425 6. Thermonuclear reactions in explosive events 427 6.1. Big Bang

  19. Lithium-Beryllium-Boron : Origin and Evolution

    E-Print Network [OSTI]

    Elisabeth Vangioni-Flam; Michel Casse; Jean Audouze

    1999-07-13T23:59:59.000Z

    The origin and evolution of Lithium-Beryllium-Boron is a crossing point between different astrophysical fields : optical and gamma spectroscopy, non thermal nucleosynthesis, Big Bang and stellar nucleosynthesis and finally galactic evolution. We describe the production and the evolution of Lithium-Beryllium-Boron from Big Bang up to now through the interaction of the Standard Galactic Cosmic Rays with the interstellar medium, supernova neutrino spallation and a low energy component related to supernova explosions in galactic superbubbles.

  20. Nucleosynthesis in Type Ia Supernovae

    E-Print Network [OSTI]

    K. Nomoto; K. Iwamoto; N. Nakasato; F. -K. Thielemann; F. Brachwitz; T. Tsujimoto; Y. Kubo; N. Kishimoto

    1997-06-03T23:59:59.000Z

    Among the major uncertainties involved in the Chandrasekhar mass models for Type Ia supernovae are the companion star of the accreting white dwarf (or the accretion rate that determines the carbon ignition density) and the flame speed after ignition. We present nucleosynthesis results from relatively slow deflagration (1.5 - 3 % of the sound speed) to constrain the rate of accretion from the companion star. Because of electron capture, a significant amount of neutron-rich species such as ^{54}Cr, ^{50}Ti, ^{58}Fe, ^{62}Ni, etc. are synthesized in the central region. To avoid the too large ratios of ^{54}Cr/^{56}Fe and ^{50}Ti/^{56}Fe, the central density of the white dwarf at thermonuclear runaway must be as low as \\ltsim 2 \\e9 \\gmc. Such a low central density can be realized by the accretion as fast as $\\dot M \\gtsim 1 \\times 10^{-7} M_\\odot yr^{-1}$. These rapidly accreting white dwarfs might correspond to the super-soft X-ray sources.

  1. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect (OSTI)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09T23:59:59.000Z

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and ?{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on ?{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  2. NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS

    E-Print Network [OSTI]

    Rauscher, Thomas

    NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS Thomas Rauscher 1 , Friedrich. of Astron. and Astroph., Univ. of California, Santa Cruz, CA 95064 Abstract The majority of nuclear­Feshbach). The global parametrizations of the nuclear properties needed for predictions far off stability probe our

  3. Modeling The Nucleosynthesis Of Massive Stars

    E-Print Network [OSTI]

    T. Rauscher

    2003-09-09T23:59:59.000Z

    This overview discusses issues relevant to modeling nucleosynthesis in type II supernovae and implications of detailed studies of the ejecta. After a brief presentation of the most common approaches to stellar evolution and parameterized explosions, the relevance of a number of nuclei to obtain information on the evolution and explosion mechanisms is discussed. The paper is concluded by an outlook on multi-dimensional simulations.

  4. Effect of nuclear structure on Type Ia supernova nucleosynthesis

    E-Print Network [OSTI]

    D. J. Dean

    2000-12-08T23:59:59.000Z

    The relationship among nuclear structure, the weak processes in nuclei, and astrophysics becomes quite apparent in supernova explosion and nucleosynthesis studies. In this brief article, I report on progress made in the last few years on calculating electron capture and beta-decay rates in iron-group nuclei. I also report on applications of these rates to Type-Ia nucleosynthesis studies.

  5. Type Ia Supernovae: Simulations and Nucleosynthesis

    E-Print Network [OSTI]

    E. F. Brown; A. C. Calder; T. Plewa; P. M. Ricker; K. Robinson; J. B. Gallagher

    2005-05-19T23:59:59.000Z

    We present our first nucleosynthesis results from a numerical simulation of the thermonuclear disruption of a static cold Chandrasekhar-mass C/O white dwarf. The two-dimensional simulation was performed with an adaptive-mesh Eulerian hydrodynamics code, FLASH, that uses as a flame capturing scheme the evolution of a passive scaler. To compute the isotopic yields and their velocity distribution, 10,000 massless tracer particles are embedded in the star. The particles are advected along streamlines and provide a Lagrangian description of the explosion. We briefly describe our verification tests and preliminary results from post-processing the particle trajectories with a modest (214 isotopes) reaction network.

  6. Cosmic Minivoids in the Intergalactic Medium

    E-Print Network [OSTI]

    Avery Meiksin

    1996-11-01T23:59:59.000Z

    The Gunn-Peterson effect, absorption of Lya photons by a homogeneous component of the intergalactic medium (IGM), potentially provides a test of Big Bang Nucleosynthesis (BBN). With a lower limit on the UV radiation field estimated from the contribution due to QSOs, a measurement of the Lya opacity of the intergalactic medium would permit the derivation of a lower bound to the baryonic density of the universe. The effect, however, has continually eluded a convincing detection, both in HI and HeII, despite extensive searches. Recent cosmological hydrodynamical simulations of structure formation in the intergalactic medium suggest an explanation for its absence. In a Cold Dark Matter dominated cosmology, the fragmentation of the baryons is nearly complete, leaving a negligible remnant to comprise a smoothly distributed component. The fragmentation extends even into regions that are underdense, where it gives rise to most of the optically thin HI systems and nearly all of the HeII systems, both thin and saturated. The result is a Lya opacity from a smooth IGM that is suppressed by over two orders of magnitude from the BBN value.

  7. Sinks of Light Elements in Stars - Part II

    E-Print Network [OSTI]

    Marc H. Pinsonneault; Corinne Charbonnel; Constantine P. Deliyannis

    2000-06-20T23:59:59.000Z

    The fragile light elements lithium, beryllium, and boron are easily destroyed in stellar interiors, and are thus superb probes of physical processes occuring in the outer stellar layers. The light elements are also excellent tracers of the chemical evolution of the Galaxy, and can test big bang nucleosynthesis (BBN). These inter-related topics are reviewed with an emphasis on stellar physics. In Part I (presented by CPD), an overview is given of the physical processes which can modify the surface abundances of the light elements, with emphasis on Population I dwarfs - convection; gravitational settling, thermal diffusion, and radiative levitation; slow mixing induced by gravity waves or rotation. We will discuss the increasingly large body of data which begin to enable us to discern the relative importance of these mechanisms in Population I main sequence stars. In Part II (presented by MHP), discussion is extended to the issue of whether or not the halo Li plateau is depleted, and includes the following topics: Li dispersion in field and globular cluster stars, Li production vs. destruction in Li-rich halo stars, and constraints from 6Li. Also discussed are trends with metal abundance and Teff and implications for chemical evolution and BBN. In Part III (presented by CC), evidence is reviewed that suggests that in situ mixing occurs in evolved low mass Population I and Population II stars. Theoretical mechanisms that can create such mixing are discussed, as well as their implications in stellar yields.

  8. Sinks of Light Elements in Stars - Part III

    E-Print Network [OSTI]

    Corinne Charbonnel; Constantine P. Deliyannis; Marc H. Pinsonneault

    2000-06-20T23:59:59.000Z

    The fragile light elements lithium, beryllium, and boron are easily destroyed in stellar interiors, and are thus superb probes of physical processes occuring in the outer stellar layers. The light elements are also excellent tracers of the chemical evolution of the Galaxy, and can test big bang nucleosynthesis (BBN). These inter-related topics are reviewed with an emphasis on stellar physics. In Part I (presented by CPD), an overview is given of the physical processes which can modify the surface abundances of the light elements, with emphasis on Population I dwarfs - convection; gravitational settling, thermal diffusion, and radiative levitation; slow mixing induced by gravity waves or rotation. We will discuss the increasingly large body of data which begin to enable us to discern the relative importance of these mechanisms in Population I main sequence stars. In Part II (presented by MHP), discussion is extended to the issue of whether or not the halo Li plateau is depleted, and includes the following topics: Li dispersion in field and globular cluster stars, Li production vs. destruction in Li-rich halo stars, and constraints from 6Li. Also discussed are trends with metal abundance and Teff and implications for chemical evolution and BBN. In Part III (presented by CC), evidence is reviewed that suggests that in situ mixing occurs in evolved low mass Population I and Population II stars. Theoretical mechanisms that can create such mixing are discussed, as well as their implications in stellar yields.

  9. The Primordial Lithium Problem

    E-Print Network [OSTI]

    Brian D. Fields

    2012-03-15T23:59:59.000Z

    Big-bang nucleosynthesis (BBN) theory, together with the precise WMAP cosmic baryon density, makes tight predictions for the abundances of the lightest elements. Deuterium and 4He measurements agree well with expectations, but 7Li observations lie a factor 3-4 below the BBN+WMAP prediction. This 4-5\\sigma\\ mismatch constitutes the cosmic "lithium problem," with disparate solutions possible. (1) Astrophysical systematics in the observations could exist but are increasingly constrained. (2) Nuclear physics experiments provide a wealth of well-measured cross-section data, but 7Be destruction could be enhanced by unknown or poorly-measured resonances, such as 7Be + 3He -> 10C^* -> p + 9B. (3) Physics beyond the Standard Model can alter the 7Li abundance, though D and 4He must remain unperturbed; we discuss such scenarios, highlighting decaying Supersymmetric particles and time-varying fundamental constants. Present and planned experiments could reveal which (if any) of these is the solution to the problem.

  10. Electron capture cross sections for stellar nucleosynthesis

    E-Print Network [OSTI]

    Giannaka, P G

    2015-01-01T23:59:59.000Z

    In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasi-particle random-phase approximation (pn-QRPA) and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the above mentioned $e^-$-capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the $^{66}Zn$ isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  11. Challenges in explosive nucleosynthesis of heavy elements

    SciTech Connect (OSTI)

    Pinedo, Gabriel Martinez; Fischer, T.; Lohs, A.; Huther, L. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, 64289 Darmstadt, Germany and GSI Helmholtzzentrum fuer Schwerioneneforschung, Planckstrasse 1, 64291 Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerioneneforschung, Planckstrasse 1, 64291 Darmstadt, Germany and Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, 64289 Darmstadt (Germany); Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, 64289 Darmstadt (Germany)

    2012-10-20T23:59:59.000Z

    We show that a treatment of charged-current neutrino interactions in hot and dense matter that is consistent with the nuclear equation of state has a strong impact on the spectra of the neutrinos emitted during the deleptonization period of a protoneutron star formed in a core-collapse supernova. We compare results of simulations including and neglecting mean field effects on the neutrino opacities. Their inclusion reduces the luminosities of all neutrino flavors and enhances the spectral differences between electron neutrino and antineutrino. The magnitude of the difference depends on the equation of state and in particular on the symmetry energy at sub-nuclear densities. These modifications reduce the proton-to-nucleon ratio of the neutrino-driven outflow, increasing slightly their entropy. They are expected to have a substantial impact on the nucleosynthesis in neutrino-driven winds, even though they do not result in conditions that favor an r-process. Contrarily to previous findings, our simulations show that the spectra of electron neutrinos remain substantially different from those of other (anti)neutrino flavors during the entire deleptonization phase of the protoneutron star. The obtained luminosity and spectral changes are also expected to have important consequences for neutrino flavor oscillations and neutrino detection on Earth.

  12. Matter, antimatter and surviving the big bang is topic of Lab...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of matter over antimatter developed, eventually leading to galaxies and stars and planets . . . and us." Talk begins at 7 p.m. and open to public LOS ALAMOS, N.M., Oct. 31,...

  13. The Planck energy-mass source as an alternative to the Big Bang

    E-Print Network [OSTI]

    Serge F. Timashev

    2008-04-17T23:59:59.000Z

    The general theory of relativity is used to show that the total energy-mass of the visible Universe could be produced by an energy-mass source with the Planck power. The source was supposedly born at the phase of cosmic inflation and acts continuously throughout the lifetime of our Universe. The model allows one to treat dark energy as a real form of energy without using the hypothesis of anti-gravity.

  14. New class of inhomogeneous cosmological perfect-fluid solutions without big-bang singularity

    SciTech Connect (OSTI)

    Senovilla, J.M.M. (Grupo de Fisica Teorica, Departamento de Fisica, Ingenieria y Radiologia Medica, Facultad de Ciencias, Universidad de Salamanca, 37008 Salmanaca (Spain))

    1990-05-07T23:59:59.000Z

    A new class of exact solutions to Einstein's field equations with a perfect-fluid source is presented. The solutions describe spatially inhomogeneous cosmological models and have a realistic equation of state {ital p}={rho}/3. The properties of the solutions are discussed. The most remarkable feature is the absence of an initial singularity, the curvature and matter invariants being regular and smooth everywhere. We also present an alternative interpretation of the solution as a globally regular cylindrically symmetric space-time.

  15. The Big Bang quantum cosmology: The matter-energy production epoch

    E-Print Network [OSTI]

    V. E. Kuzmichev; V. V. Kuzmichev

    2008-04-30T23:59:59.000Z

    The exactly solvable quantum model of the homogeneous, isotropic and closed universe in the matter-energy production epoch is considered. It is assumed that the universe is originally filled with a uniform scalar field and a perfect fluid which defines a reference frame. The stationary state spectrum and the wave functions of the quantum universe are calculated. In this model the matter-energy in the universe has a component in the form of a condensate of massive zero-momentum excitation quanta of oscillations of primordial scalar field. The mean value of the scale factor of the universe in a given state is connected with the mass of a condensate by a linear relation. The nucleation rate of the universe from the initial cosmological singularity point is calculated. It is demonstrated that the process of nucleation of the universe can have an exponential (explosive) nature. The evolution of the universe is described as transitions with non-zero probabilities between the states of the universe with different masses of a condensate.

  16. Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation

    SciTech Connect (OSTI)

    Hargadon, Andrew [University of California, Davis

    2012-10-22T23:59:59.000Z

    Calls for breakthroughs in science and technology have never been louder, and yet the demand for innovation is made more challenging by public and political misconceptions surrounding where, when, and how it happens. Professor Andrew Hargadon uses historical research to advance our current understanding of the innovation process. He discussed the social and technical context in which electric light, and the modern electric power infrastructure, were born and considers its implications for managing innovation in science and technology today.

  17. Big Bang Day : The Great Big Particle Adventure - 2. Who Ordered That?

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    In this series, comedian and physicist Ben Miller asks the CERN scientists what they hope to find. The atoms that make up our material world are important to us, but it turns out they aren't so significant on the cosmic stage. In fact early in the search for the stuff of atoms, researchers discovered particles that played no part in Earthly chemistry - for example particles in cosmic rays that resemble electrons (the stuff of electricity and the chemical glue in molecules) in almost all respects except that they weigh 140 times more. "Who ordered that?" one Nobel laureate demanded. They also discovered antimatter - the destructive mirror-image particles at obliterate all matter they come into contact with. In fact, the Universe is mostly made up of particles that could never make atoms, so that we are just the flotsam of the cosmos. But the main constituent of the Universe, what makes 80% of creation, has never been seen in the lab. Researchers at CERN believe they can create samples of it, down here on Earth.

  18. The Planck energy-mass source as an alternative to the Big Bang

    E-Print Network [OSTI]

    Timashev, Serge F

    2008-01-01T23:59:59.000Z

    The general theory of relativity is used to show that the total energy-mass of the visible Universe could be produced by an energy-mass source with the Planck power. The source was supposedly born at the phase of cosmic inflation and acts continuously throughout the lifetime of our Universe. The model allows one to treat dark energy as a real form of energy without using the hypothesis of anti-gravity.

  19. The Rise of Big Bang Models, from Myth to Theory and Observations

    E-Print Network [OSTI]

    Luminet, Jean Pierre

    2007-01-01T23:59:59.000Z

    We provide an epistemological analysis of the developments of relativistic cosmology from 1917 to 2006, based on the seminal articles by Einstein, de Sitter, Friedmann, Lemaitre, Hubble, Gamow and other main historical figures of the field. It appears that most of the ingredients of the present-day standard cosmological model, such as the accelation of the expansion due to a repulsive dark energy, the interpretation of the cosmological constant as vacuum energy or the possible non-trivial topology of space, had been anticipated by Lemaitre, although his papers remain desperately unquoted.

  20. DOE research makes big bang | OSTI, US Dept of Energy, Office of Scientific

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management Fermi SitePARTOffice ofHale Plan by(formerlyand Technical

  1. Supercomputing: A Toolbox to Simulate the Big Bang and Beyond | Department

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov. Are you sure you wantJoin us for|Idaho |Energy Supercomputers: Extreme

  2. Jetting into the Moments after the Big Bang | U.S. DOE Office of Science

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron4 Self-Scrubbing:,,ofOpportunitieshighlights/ Theisc/about/jobs/

  3. Neutrinos' Instant Identity Changes Could Mean Big Things for the Big Bang

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed offOCHCO2:Introduction toManagement ofConverDynNet-Zero Campus at University of California,|

  4. PPPL, Princeton launch hunt for Big Bang particles offering clues to the

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomass and4/26/11:Tel.:162Physics|station |PhysicsPPPL'sorigin of

  5. NERSC User Group 2013 Big Bang, Big Data, Big Iron Planck Satellite Data Analysis At NERSC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Saleshttp://www.fnal.gov/directorate/nalcal/nalcal02_07_05_files/nalcal.gif Directorate - Events:00---9:30 Registration a ndDay2013 Big

  6. Supercomputing: A Toolbox to Simulate the Big Bang and Beyond | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreakingMayDepartment of StaffingStorageEnergy 2,Super Bowlof Energy

  7. Big Bang or Big Bounce? Professor Paul J. Steinhardt Princeton University

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find MoreLawrenceDepartment ofBicycle Safety

  8. Matter, antimatter and surviving the big bang is topic of Lab's next

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home andDisposition |MaterialsMatt Dozier About

  9. COLLOQUIUM: One Second After the Big Bang | Princeton Plasma Physics Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisiting the TWPSuccess StoriesFebruary 26, 2014, 4:00pm to| PrincetonPrincetonOctober

  10. The Decay of the Neutron or Beta Decay, the Big Bang, and the Left-Handed

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening a solidSynthesis of 2Dand Water |1Benefits of 3DDale E.

  11. Heavy element nucleosynthesis in jets from collapsars

    SciTech Connect (OSTI)

    Fujimoto, Shin-ichirou [Department of Electronic Control, Kumamoto National College of Technology, Kumamoto 861-1102 (Japan); Institut d'Astronomie et d'Astrophysique, Universite libre de Bruxelles, CP226 Boulevard du Triomphe, B-1050 Brussels (Belgium); Hashimoto, Masa-aki [Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Kotake, Kei [Division of Theoretical Astronomy, National Astronomical Observatory Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Yamada, Shoichi [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)

    2007-02-26T23:59:59.000Z

    We investigate nucleosynthesis in collapsars, based on long-term, magnetohydrodynamic simulations of a rapidly rotating massive star of 40M{center_dot} during the core collapse. We have calculated detailed composition of magnetically driven jets ejected from the collapsars, in which the magnetic fields before the collapse, are uniform and parallel to the rotational axis of the star and the magnitudes of the fields, B0, are 1010 G or 1012 G. We follow the evolution of chemical composition up to about 4000 nuclides inside the jets from the collapse phase to the ejection phase through the jet generation phase with use of a large nuclear reaction network. We find that the r-process successfully operates in the jets from the collapsar of B0 = 1012 G, so that U and Th are synthesized abundantly. Abundance pattern inside the jets is similar to that of r-elements in the solar system. Furthermore, we find that p-nuclei are produced without seed nuclei: not only light p-nuclei, such as 74Se, 78Kr, 84Sr, and 92Mo, but also heavy p-nuclei, 113In, 115Sn, and 138La, can be abundantly synthesized in the jets. The amounts of p-nuclei in the ejecta are much greater than those in core-collapse supernovae (SNe). In particular, 92Mo, 113In, 115Sn, and 138La deficient in the SNe, are significantly produced in the ejecta. On the other hand, in the jets from the collapsar of B0 = 1010 G, the r-process cannot operate and 56Ni, 28Si, 32S, and 4He are abundantly synthesized in the jets, as in ejecta from inner layers of Type II supernovae. An amount of 56Ni is much smaller than that from SN 1987A.

  12. Primordial Li abundance and massive particles

    SciTech Connect (OSTI)

    Latin-Capital-Letter-Eth apo, H. [Department of Physics, Akdeniz University, TR-07058, Antalya (Turkey)

    2012-10-20T23:59:59.000Z

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on {sup 4}HeX{sup -}+{sup 2}H{yields}{sup 6}Li+X{sup -}, where the X{sup -} is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  13. Neutrinos and nucleosynthesis in core-collapse supernovae

    SciTech Connect (OSTI)

    Fröhlich, C.; Casanova, J. [Department of Physics, North Carolina State University, Raleigh, NC, 27695 (United States); Hempel, M.; Liebendörfer, M. [Departement für Physik, Universität Basel, CH-4056 Basel (Switzerland); Melton, C. A. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Perego, A. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany)

    2014-01-01T23:59:59.000Z

    Massive stars (M > 8-10 M{sub ?}) undergo core collapse at the end of their life and explode as supernova with ~ 10?¹ erg of kinetic energy. While the detailed supernova explosion mechanism is still under investigation, reliable nucleosynthesis calculations based on successful explosions are needed to explain the observed abundances in metal-poor stars and to predict supernova yields for galactic chemical evolution studies. To predict nucleosynthesis yields for a large number of progenitor stars, computationally efficient explosion models are required. We model the core collapse, bounce and subsequent explosion of massive stars assuming spherical symmetry and using detailed microphysics and neutrino physics combined with a novel method to artificially trigger the explosion (PUSH). We discuss the role of neutrinos, the conditions in the ejecta, and the resulting nucleosynthesis.

  14. Cosmological and supernova neutrinos

    SciTech Connect (OSTI)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Balantekin, A. B. [Department of Physics, University of Wisconsin - Madison, Wisconsin 53706 (United States); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Kusakabe, M. [School of Liberal Arts and Science, Korea Aerospace University, Goyang 412-791 (Korea, Republic of); Mathews, G. J. [Department of Physics, University of Notre Dame, IN 46556 (United States); Nakamura, K. [Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Pehlivan, Y. [Mimar Sinan GSÜ, Department of Physics, ?i?li, ?stanbul 34380 (Turkey); Suzuki, T. [Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-06-24T23:59:59.000Z

    The Big Bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) anisotropies are the pillars of modern cosmology. It has recently been suggested that axion which is a dark matter candidate in the framework of the standard model could condensate in the early universe and induce photon cooling before the epoch of the photon last scattering. Although this may render a solution to the overproduction problem of primordial {sup 7}Li abundance, there arises another serious difficulty of overproducing D abundance. We propose a hybrid dark matter model with both axions and relic supersymmetric (SUSY) particles to solve both overproduction problems of the primordial D and {sup 7}Li abundances simultaneously. The BBN also serves to constrain the nature of neutrinos. Considering non-thermal photons produced in the decay of the heavy sterile neutrinos due to the magnetic moment, we explore the cosmological constraint on the strength of neutrino magnetic moment consistent with the observed light element abundances. Core-collapse supernovae eject huge flux of energetic neutrinos which affect explosive nucleosynthesis of rare isotopes like {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta and r-process elements. Several isotopes depend strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. Combining the recent experimental constraints on ?{sub 13} with predicted and observed supernova-produced abundance ratio {sup 11}B/{sup 7}Li encapsulated in the presolar grains from the Murchison meteorite, we show a marginal preference for an inverted neutrino mass hierarchy. We also discuss supernova relic neutrinos (SRN) that may indicate the softness of the equation of state (EoS) of nuclear matter and adiabatic conditions of the neutrino oscillation.

  15. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

    Iliadis, Christian; Coc, Alain; Timmes, F X; Champagne, Art E

    2014-01-01T23:59:59.000Z

    Rigorous statistical methods for estimating thermonuclear reaction rates and nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and gamma-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples ...

  16. Heavy sterile neutrinos, entropy and relativistic energy production, and the relic neutrino background

    E-Print Network [OSTI]

    Fuller, George M; Kusenko, Alexander

    2011-01-01T23:59:59.000Z

    We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with couplings to ordinary active neutrinos large enough to guarantee thermal and chemical equilibrium at epochs in the early universe with temperatures T > 1 GeV, but in a range to give decay lifetimes from seconds to minutes. Such neutrinos would decouple early, with relic densities comparable to those of photons, but decay out of equilibrium, with consequent prodigious entropy generation prior to, or during, Big Bang Nucleosynthesis (BBN). Most of the ranges of sterile neutrino rest mass and lifetime considered are at odds with Cosmic Microwave Background (CMB) limits on the relativistic particle contribution to energy density (e.g., as parameterized by N_eff). However, some sterile neutrino parameters can lead to an acceptable N_eff. These parameter ranges are accompanie...

  17. Sterile Neutrinos with Secret Interactions - Lasting Friendship with Cosmology

    E-Print Network [OSTI]

    Xiaoyong Chu; Basudeb Dasgupta; Joachim Kopp

    2015-05-11T23:59:59.000Z

    Sterile neutrinos with mass ~1 eV and order 10% mixing with active neutrinos have been proposed as a solution to anomalies in neutrino oscillation data, but are tightly constrained by cosmological limits. It was recently shown that these constraints are avoided if sterile neutrinos couple to a new MeV-scale gauge boson A'. However, even this scenario is restricted by structure formation constraints when A'-mediated collisional processes lead to efficient active-to-sterile neutrino conversion after neutrinos have decoupled. In view of this, we reevaluate in this paper the viability of sterile neutrinos with such "secret" interactions. We carefully dissect their evolution in the early Universe, including the various production channels and the expected modifications to large scale structure formation. We argue that there are two regions in parameter space - one at very small A' coupling, one at relatively large A' coupling - where all constraints from big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and large scale structure (LSS) data are satisfied. Interestingly, the large A' coupling region is precisely the region that was previously shown to have potentially important consequences for the small scale structure of dark matter halos if the A' boson couples also to the dark matter in the Universe.

  18. Nucleosynthesis in the accretion disks of Type II collapsars

    E-Print Network [OSTI]

    Indrani Banerjee; Banibrata Mukhopadhyay

    2013-05-08T23:59:59.000Z

    We investigate nucleosynthesis inside the gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, the core collapse of massive stars first leads to the formation of a proto-neutron star and a mild supernova explosion is driven. However, this supernova ejecta lack momentum and falls back onto the neutron star which gets transformed to a stellar mass black hole. In order to study the hydrodynamics and nucleosynthesis of such an accretion disk formed from the fallback material of the supernova ejecta, we use the well established hydrodynamic models. In such a disk neutrino cooling becomes important in the inner disk where the temperature and density are higher. Higher the accretion rate (dot{M}), higher is the density and temperature in the disks. In this work we deal with accretion disks with relatively low accretion rates: 0.001 M_sun s^{-1} \\lesssim dot{M} \\lesssim 0.01 M_sun s^{-1} and hence these disks are predominantly advection dominated. We use He-rich and Si-rich abundances as the initial condition of nucleosynthesis at the outer disk, and being equipped with the disk hydrodynamics and the nuclear network code, we study the abundance evolution as matter inflows and falls into the central object. We investigate the variation in the nucleosynthesis products in the disk with the change in the initial abundance at the outer disk and also with the change in the mass accretion rate. We report the synthesis of several unusual nuclei like {31}P, {39}K, {43}Sc, {35}Cl, and various isotopes of titanium, vanadium, chromium, manganese and copper. We also confirm that isotopes of iron, cobalt, nickel, argon, calcium, sulphur and silicon get synthesized in the disk, as shown by previous authors. Much of these heavy elements thus synthesized are ejected from the disk via outflows and hence they should leave their signature in observed data.

  19. Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity

    E-Print Network [OSTI]

    Woosley, S E

    2007-01-01T23:59:59.000Z

    Hans Bethe contributed in many ways to our understanding of the supernovae that happen in massive stars, but, to this day, a first principles model of how the explosion is energized is lacking. Nevertheless, a quantitative theory of nucleosynthesis is possible. We present a survey of the nucleosynthesis that occurs in 32 stars of solar metallicity in the mass range 12 to 120 solar masses. The most recent set of solar abundances, opacities, mass loss rates, and current estimates of nuclear reaction rates are employed. Restrictions on the mass cut and explosion energy of the supernovae based upon nucleosynthesis, measured neutron star masses, and light curves are discussed and applied. The nucleosynthetic results, when integrated over a Salpeter initial mass function (IMF), agree quite well with what is seen in the sun. We discuss in some detail the production of the long lived radioactivities, 26Al and 60Fe, and why recent model-based estimates of the ratio 60Fe/26Al are overly large compared with what satelli...

  20. The Primordial Helium Abundance

    E-Print Network [OSTI]

    Manuel Peimbert

    2008-11-18T23:59:59.000Z

    I present a brief review on the determination of the primordial helium abundance by unit mass, Yp. I discuss the importance of the primordial helium abundance in: (a) cosmology, (b) testing the standard big bang nucleosynthesis, (c) studying the physical conditions in H II regions, (d) providing the initial conditions for stellar evolution models, and (e) testing the galactic chemical evolution models.

  1. Solving Cosmological Problems of Supersymmetric Axion Models in an Inflationary Universe

    E-Print Network [OSTI]

    Masahiro Kawasaki; Kazunori Nakayama

    2008-04-28T23:59:59.000Z

    We revisit inflationary cosmology of axion models in the light of recent developments on the inflaton decay in supergravity. We find that all the cosmological difficulties, including gravitino, axino overproduction and axionic isocurvature fluctuation, can be avoided if the saxion field has large initial amplitude during inflation and decays before big-bang nucleosynthesis.

  2. Non Thermal Features in the Cosmic Neutrino Background

    E-Print Network [OSTI]

    G. Mangano

    2006-03-22T23:59:59.000Z

    I review some of the basic information on the Cosmic Neutrino Background momentum distribution. In particular, I discuss how present data from several cosmological observables such as Big Bang Nucleosynthesis, Cosmic Microwave Background and Large Scale Structure power spectrum constrain possible deviations from a standard Fermi-Dirac thermal distribution.

  3. Nuclear physics and cosmology

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS/IN2P3, Université Paris Sud 11, UMR 8609, Bâtiment 104, F-91405 Orsay Campus (France)

    2014-05-09T23:59:59.000Z

    There are important aspects of Cosmology, the scientific study of the large scale properties of the universe as a whole, for which nuclear physics can provide insights. Here, we will focus on Standard Big-Bang Nucleosynthesis and we refer to the previous edition of the School [1] for the aspects concerning the variations of constants in nuclear cosmo-physics.

  4. Physics 554 Astronomy 510

    E-Print Network [OSTI]

    Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

    Physics 554 Astronomy 510 Nuclear Astrophysics Winter 2004 Chapter 1 Big Bang Nucleosynthesis 1 universe comes from nuclear physics, the elemental abundances we can measure on the sun's surface by mass are 1 H 0.75 4 He 0.25 We will see that these elements owe their abundances primarily to nuclear

  5. Cosmology and the weak interaction

    SciTech Connect (OSTI)

    Schramm, D.N. (Fermi National Accelerator Lab., Batavia, IL (USA)):(Chicago Univ., IL (USA))

    1989-12-01T23:59:59.000Z

    The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.

  6. Revisiting shock-driven exploding pushers: Insights into plasma flows and fields, stopping power, nucleosynthesis, and

    E-Print Network [OSTI]

    topics such as nucleosynthesis and kinetic and/or multi-ion fluid phenomena. For nucleosynthesis the fuel plasma density is sufficiently low and the temperature sufficiently high. Such conditions lend domain, the issue of multi-ion fluid effects, as opposed to the "average" single-ion fluid approximation

  7. Collaborative Research: Neutrinos & Nucleosynthesis in Hot Dense Matter

    SciTech Connect (OSTI)

    Reddy, Sanjay

    2013-09-06T23:59:59.000Z

    It is now firmly established that neutrinos, which are copiously produced in the hot and dense core of the supernova, play a role in the supernova explosion mechanism and in the synthesis of heavy elements through a phenomena known as r-process nucleosynthesis. They are also detectable in terrestrial neutrino experiments, and serve as a probe of the extreme environment and complex dynamics encountered in the supernova. The major goal of the UW research activity relevant to this project was to calculate the neutrino interaction rates in hot and dense matter of relevance to core collapse supernova. These serve as key input physics in large scale computer simulations of the supernova dynamics and nucleosynthesis being pursued at national laboratories here in the United States and by other groups in Europe and Japan. Our calculations show that neutrino production and scattering rate are altered by the nuclear interactions and that these modifications have important implications for nucleosynthesis and terrestrial neutrino detection. The calculation of neutrino rates in dense matter are difficult because nucleons in the dense matter are strongly coupled. A neutrino interacts with several nucleons and the quantum interference between scattering off different nucleons depends on the nature of correlations between them in dense matter. To describe these correlations we used analytic methods based on mean field theory and hydrodynamics, and computational methods such as Quantum Monte Carlo. We found that due to nuclear effects neutrino production rates at relevant temperatures are enhanced, and that electron neutrinos are more easily absorbed than anti-electron neutrinos in dense matter. The latter, was shown to favor synthesis of heavy neutron-rich elements in the supernova.

  8. Heavy sterile neutrinos, entropy and relativistic energy production, and the relic neutrino background

    E-Print Network [OSTI]

    George M. Fuller; Chad T. Kishimoto; Alexander Kusenko

    2011-10-28T23:59:59.000Z

    We explore the implications of the existence of heavy neutral fermions (i.e., sterile neutrinos) for the thermal history of the early universe. In particular, we consider sterile neutrinos with rest masses in the 100 MeV to 500 MeV range, with couplings to ordinary active neutrinos large enough to guarantee thermal and chemical equilibrium at epochs in the early universe with temperatures T > 1 GeV, but in a range to give decay lifetimes from seconds to minutes. Such neutrinos would decouple early, with relic densities comparable to those of photons, but decay out of equilibrium, with consequent prodigious entropy generation prior to, or during, Big Bang Nucleosynthesis (BBN). Most of the ranges of sterile neutrino rest mass and lifetime considered are at odds with Cosmic Microwave Background (CMB) limits on the relativistic particle contribution to energy density (e.g., as parameterized by N_eff). However, some sterile neutrino parameters can lead to an acceptable N_eff. These parameter ranges are accompanied by considerable dilution of the ordinary background relic neutrinos, possibly an adverse effect on BBN, but sometimes fall in a range which can explain measured neutrino masses in some particle physics models. A robust signature of these sterile neutrinos would be a measured N_eff not equal to 3 coupled with no cosmological signal for neutrino rest mass when the detection thresholds for these probes are below laboratory-established neutrino mass values, either as established by the atmospheric neutrino oscillation scale or direct measurements with, e.g., KATRIN or neutrino-less double beta decay experiments.

  9. Reconciling thermal leptogenesis with the gravitino problem in SUSY models with mixed axion/axino dark matter

    SciTech Connect (OSTI)

    Baer, Howard; Lessa, Andre [Dept. of Physics and Astronomy, University of Oklahoma, 440 West Brooks, Norman, OK 73019 (United States); Kraml, Sabine [Laboratoire de Physique Subatomique et de Cosmologie, UJF Grenoble 1, CNRS/IN2P3, INPG, 53 Avenue des Martyrs, F-38026 Grenoble (France); Sekmen, Sezen, E-mail: baer@nhn.ou.edu, E-mail: sabine.kraml@lpsc.in2p3.fr, E-mail: lessa.a.p@gmail.com, E-mail: sezen.sekmen@cern.ch [Dept. of Physics, Florida State University, 513 Keen Bldg., Tallahassee, FL 32306 (United States)

    2010-11-01T23:59:59.000Z

    Successful implementation of thermal leptogenesis requires re-heat temperatures T{sub R}?>2 × 10{sup 9} GeV, in apparent conflict with SUSY models with TeV-scale gravitinos, which require much lower T{sub R} in order to avoid Big Bang Nucleosynthesis (BBN) constraints. We show that mixed axion/axino dark matter can reconcile thermal leptogenesis with the gravitino problem in models with m{sub G-tilde}?>30 TeV, a rather high Peccei-Quinn breaking scale and an initial mis-alignment angle ?{sub i} < 1. We calculate axion and axino dark matter production from four sources, and impose BBN constraints on long-lived gravitinos and neutralinos. Moreover, we discuss several SUSY models which naturally have gravitino masses of the order of tens of TeV. We find a reconciliation difficult in Yukawa-unified SUSY and in AMSB with a wino-like lightest neutralino. However, T{sub R} ? 10{sup 10}?10{sup 12} GeV can easily be achieved in effective SUSY and in models based on mixed moduli-anomaly mediation. Consequences of this scenario include: 1. an LHC SUSY discovery should be consistent with SUSY models with a large gravitino mass, 2. an apparent neutralino relic abundance ?{sub Z-tilde} {sub 1}h{sup 2}?<1, 3. no WIMP direct or indirect detection signals should be found, and 4. the axion mass should be less than ? 10{sup ?6} eV, somewhat below the conventional range which is explored by microwave cavity axion detection experiments.

  10. Sterile Neutrinos and Light Dark Matter Save Each Other

    E-Print Network [OSTI]

    Chiu Man Ho; Robert J. Scherrer

    2013-03-13T23:59:59.000Z

    Short baseline neutrino experiments such as LSND and MiniBooNE seem to suggest the existence of light sterile neutrinos. Meanwhile, current cosmic microwave background (CMB) and big bang nucleosynthesis (BBN) measurements place an upper bound on the effective number of light neutrinos, $N_{eff}$ and the PLANCK satellite will measure $N_{eff}$ to a much higher accuracy and further constrain the number of sterile neutrinos allowed. We demonstrate that if an MeV dark matter particle couples more strongly to electrons and/or photons than to neutrinos, then p-wave annihilation after neutrino decoupling can reduce the value of $N_{eff}$ inferred from BBN and PLANCK. This mechanism can accommodate two eV sterile neutrinos even if PLANCK observes $N_{eff}$ as low as the standard model theoretical value of 3.046, and a large neutrino asymmetry is not needed to obtain the correct primordial element abundances. The dark matter annihilation also weakens the cosmological upper bounds on the neutrino masses, and we derive a relationship between the change in these bounds and the corresponding change in $N_{eff}$. Dark matter with an electric dipole moment or anapole moment is a natural candidate that exhibits the desired properties for this mechanism. Coincidentally, a dark matter particle with these properties and lighter than 3 MeV is precisely one that can explain the 511 keV gamma-ray line observed by INTEGRAL. We show that the addition of two eV sterile neutrinos allows this kind of dark matter to be lighter than 3 MeV, which is otherwise ruled out by the CMB bound on $N_{eff}$ if only active neutrinos are considered.

  11. Nucleosynthesis in the Outflow from Gamma Ray Burst Accretion Disks

    E-Print Network [OSTI]

    R. Surman; G. C. McLaughlin; W. R. Hix

    2005-09-13T23:59:59.000Z

    We examine the nucleosynthesis products that are produced in the outflow from rapidly accreting disks. We find that the type of element synthesis varies dramatically with the degree of neutrino trapping in the disk and therefore the accretion rate of the disk. Disks with relatively high accretion rates such as 10 M_solar/s can produce very neutron rich nuclei that are found in the r process. Disks with more moderate accretion rates can produce copious amounts of Nickel as well as the light elements such as Lithium and Boron. Disks with lower accretion rates such as 0.1 M_solar/s produce large amounts of Nickel as well as some unusual nuclei such as Ti-49, Sc-45, Zn-64, and Mo-92. This wide array of potential nucleosynthesis products is due to the varying influence of electron neutrinos and antineutrinos emitted from the disk on the neutron-to-proton ratio in the outflow. We use a parameterization for the outflow and discuss our results in terms of entropy and outflow acceleration.

  12. Neutrino-driven wind simulations and nucleosynthesis of heavy elements

    E-Print Network [OSTI]

    A. Arcones; F. -K. Thielemann

    2012-07-11T23:59:59.000Z

    Neutrino-driven winds, which follow core-collapse supernova explosions, present a fascinating nuclear astrophysics problem that requires understanding advanced astrophysics simulations, the properties of matter and neutrino interactions under extreme conditions, the structure and reactions of exotic nuclei, and comparisons against forefront astronomical observations. The neutrino-driven wind has attracted vast attention over the last 20 years as it was suggested to be a candidate for the astrophysics site where half of the heavy elements are produced via the r-process. In this review, we summarize our present understanding of neutrino-driven winds from the dynamical and nucleosynthesis perspectives. Rapid progress has been made during recent years in understanding the wind with improved simulations and better micro physics. The current status of the fields is that hydrodynamical simulations do not reach the extreme conditions necessary for the r-process and the proton or neutron richness of the wind remains to be investigated in more detail. However, nucleosynthesis studies and observations point already to neutrino-driven winds to explain the origin of lighter heavy elements, such as Sr, Y, Zr.

  13. Neutron-capture nucleosynthesis in the first stars

    SciTech Connect (OSTI)

    Roederer, Ian U. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Preston, George W.; Thompson, Ian B.; Shectman, Stephen A. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sneden, Christopher, E-mail: iur@umich.edu [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States)

    2014-04-01T23:59:59.000Z

    Recent studies suggest that metal-poor stars enhanced in carbon but containing low levels of neutron-capture elements may have been among the first to incorporate the nucleosynthesis products of the first generation of stars. We have observed 16 stars with enhanced carbon or nitrogen using the MIKE Spectrograph on the Magellan Telescopes at Las Campanas Observatory and the Tull Spectrograph on the Smith Telescope at McDonald Observatory. We present radial velocities, stellar parameters, and detailed abundance patterns for these stars. Strontium, yttrium, zirconium, barium, europium, ytterbium, and other heavy elements are detected. In four stars, these heavy elements appear to have originated in some form of r-process nucleosynthesis. In one star, a partial s-process origin is possible. The origin of the heavy elements in the rest of the sample cannot be determined unambiguously. The presence of elements heavier than the iron group offers further evidence that zero-metallicity rapidly rotating massive stars and pair instability supernovae did not contribute substantial amounts of neutron-capture elements to the regions where the stars in our sample formed. If the carbon- or nitrogen-enhanced metal-poor stars with low levels of neutron-capture elements were enriched by products of zero-metallicity supernovae only, then the presence of these heavy elements indicates that at least one form of neutron-capture reaction operated in some of the first stars.

  14. Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers

    E-Print Network [OSTI]

    Just, Oliver; Pulpillo, Ricard Ardevol; Goriely, Stephane; Janka, H -Thomas

    2015-01-01T23:59:59.000Z

    We present a comprehensive study of r-process element nucleosynthesis in the ejecta of compact binary mergers (CBMs) and their relic black-hole (BH)-torus systems. The evolution of the BH-accretion tori is simulated for seconds with a Newtonian hydrodynamics code including viscosity effects, pseudo-Newtonian gravity for rotating BHs, and an energy-dependent two-moment closure scheme for the transport of electron neutrinos and antineutrinos. The investigated cases are guided by relativistic double neutron star (NS-NS) and NS-BH merger models, producing ~3-6 Msun BHs with rotation parameters of A~0.8 and tori of 0.03-0.3 Msun. Our nucleosynthesis analysis includes the dynamical (prompt) ejecta expelled during the CBM phase and the neutrino and viscously driven outflows of the relic BH-torus systems. While typically ~20-25% of the initial accretion-torus mass are lost by viscously driven outflows, neutrino-powered winds contribute at most another ~1%, but neutrino heating enhances the viscous ejecta significantl...

  15. Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae

    SciTech Connect (OSTI)

    Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park; Mizuta, Akira; /Garching, Max Planck Inst.; Sato, Katsuhiko; /Tokyo U. /Tokyo U., RESCEU

    2006-09-21T23:59:59.000Z

    Two-dimensional hydrodynamic simulations are performed to investigate explosive nucleosynthesis in a collapsar using the model of MacFadyen and Woosley (1999). It is shown that {sup 56}Ni is not produced in the jet of the collapsar sufficiently to explain the observed amount of a hypernova when the duration of the explosion is {approx} 10 sec, which is considered to be the typical timescale of explosion in the collapsar model. Even though a considerable amount of {sup 56}Ni is synthesized if all explosion energy is deposited initially, the opening angles of the jets become too wide to realize highly relativistic outflows and gamma-ray bursts in such a case. From these results, it is concluded that the origin of {sup 56}Ni in hypernovae associated with GRBs is not the explosive nucleosynthesis in the jet. We consider that the idea that the origin is the explosive nucleosynthesis in the accretion disk is more promising. We also show that the explosion becomes bi-polar naturally due to the effect of the deformed progenitor. This fact suggests that the {sup 56}Ni synthesized in the accretion disk and conveyed as outflows are blown along to the rotation axis, which will explain the line features of SN 1998bw and double peaked line features of SN 2003jd. Some fraction of the gamma-ray lines from {sup 56}Ni decays in the jet will appear without losing their energies because the jet becomes optically thin before a considerable amount of {sup 56}Ni decays as long as the jet is a relativistic flow, which may be observed as relativistically Lorentz boosted line profiles in future. We show that abundance of nuclei whose mass number {approx} 40 in the ejecta depends sensitively on the energy deposition rate, which is a result of incomplete silicon burning and alpha-rich freezeout. So it may be determined by observations of chemical composition in metal poor stars which model is the proper one as a model of a gamma-ray burst accompanied by a hypernova.

  16. Nucleosynthesis of heavy elements in gamma ray bursts

    E-Print Network [OSTI]

    ,

    2015-01-01T23:59:59.000Z

    The ultrarelativistic jets responsible for prompt and afterglow emission in gamma ray bursts are presumably driven by a central engine that consists of a dense accretion disk around a spinning black hole. We consider such engine, composed of free nucleons, electron-positron pairs, Helium nuclei, and cooled by neutrino emission. A significant number density of neutrons in the disk provide conditions for neutron rich plasma in the outflows and jets. Heavy nuclei are also formed in the accretion flow, at the distances 150-250 gravitational radii from the black hole. We study the process of nucleosynthesis in the GRB engine, depending on its physical properties. Our results may have important observational implications for the jet deceleration process and heavy elements observed in the spectra of GRB afterglows.

  17. Beta decay rates for nuclei with 115 < A < 140 for r-process nucleosynthesis

    E-Print Network [OSTI]

    Kamales Kar; Soumya Chakravarti; V. R. Manfredi

    2006-03-19T23:59:59.000Z

    For r-process nucleosynthesis the beta decay rates for a number of neutron-rich intermediate heavy nuclei are calculated. The model for the beta strength function is able to reproduce the observed half~lives quite well.

  18. Supernova nucleosynthesis and the physics of neutrino oscillation

    SciTech Connect (OSTI)

    Kajino, Toshitaka [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan) and Department of Astronomy, Graduate School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-11-20T23:59:59.000Z

    We studied the explosive nucleosynthesis in core-collapse supernovae and found that several isotopes of rare elements like {sup 7}Li, {sup 11}B, {sup 138}La, {sup 180}Ta and others are predominantly produced by the neutrino interactions with several abundant nuclei. These isotopes are strongly affected by the neutrino flavor oscillation due to the MSW (Mikheyev-Smirnov-Wolfenstein) effect. We here first study how to know the suitable average neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the neutrino oscillation effects on their abundances, and propose a new novel method to determine the neutrino oscillation parameters, {theta}{sub 13} and mass hierarchy, simultaneously. There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced neutrino-process {sup 11}B and {sup 7}Li encapsulated in the grains. Combining the recent experimental constraints on {theta}{sub 13}, we show that although the uncertainties are still large, our method hints at a marginal preference for an inverted neutrino mass hierarchy for the first time.

  19. The r-process nucleosynthesis: Nuclear physics challenges

    SciTech Connect (OSTI)

    Goriely, S. [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles Campus de la Plaine, CP 226, 1050 Brussels (Belgium)

    2012-10-20T23:59:59.000Z

    About half of the nuclei heavier than iron observed in nature are produced by the socalled rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved and for which essentially no experimental data exist. The present contribution emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Their impact on the r-abundance distribution resulting from the decompression of neutron star matter is discussed.

  20. Pasta Nucleosynthesis: Molecular dynamics simulations of nuclear statistical equilibrium

    E-Print Network [OSTI]

    M. E. Caplan; A. S. Schneider; C. J. Horowitz; D. K. Berry

    2014-12-29T23:59:59.000Z

    Background: Exotic non-spherical nuclear pasta shapes are expected in nuclear matter at just below saturation density because of competition between short range nuclear attraction and long range Coulomb repulsion. Purpose: We explore the impact of nuclear pasta on nucleosynthesis, during neutron star mergers, as cold dense nuclear matter is ejected and decompressed. Methods: We perform classical molecular dynamics simulations with 51200 and 409600 nucleons, that are run on GPUs. We expand our simulation region to decompress systems from an initial density of 0.080 fm^{-3} down to 0.00125 fm^{-3}. We study proton fractions of Y_P=0.05, 0.10, 0.20, 0.30, and 0.40 at T =0.5, 0.75, and 1.0 MeV. We calculate the composition of the resulting systems using a cluster algorithm. Results: We find final compositions that are in good agreement with nuclear statistical equilibrium models for temperatures of 0.75 and 1 MeV. However, for proton fractions greater than Y_P=0.2 at a temperature of T = 0.5 MeV, the MD simulations produce non-equilibrium results with large rod-like nuclei. Conclusions: Our MD model is valid at higher densities than simple nuclear statistical equilibrium models and may help determine the initial temperatures and proton fractions of matter ejected in mergers.

  1. The Effects of Thermonuclear Reaction Rate Variations on Nova Nucleosynthesis: A Sensitivity Study

    E-Print Network [OSTI]

    Christian Iliadis; Art Champagne; Jordi Jose; Sumner Starrfield; Paul Tupper

    2002-06-03T23:59:59.000Z

    We investigate the effects of thermonuclear reaction rate uncertainties on nova nucleosynthesis. One-zone nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the nucleosynthesis takes place). We obtain our profiles from 7 different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak=0.145-0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A=40. In total, we performed 7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction rate evaluations for the mass ranges A=1-20 and A=20-40. For the theoretical astrophysicist, our results indicate the extent to which nova nucleosynthesis calculations depend on presently uncertain nuclear physics input, while for the experimental nuclear physicist our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction rate estimates are reliable for predictions of Li, Be, C and N abundances in nova nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl and Ar abundances. Results are presented in tabular form for each adopted nova simulation.

  2. Sensitivity study of explosive nucleosynthesis in Type Ia supernovae: I. Modification of individual thermonuclear reaction rates

    E-Print Network [OSTI]

    Eduardo Bravo; Gabriel Martínez-Pinedo

    2012-04-09T23:59:59.000Z

    We explore the sensitivity of the nucleosynthesis due to type Ia supernovae with respect to uncertainties in nuclear reaction rates. We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf, and have post-processed the thermodynamic trajectories of every mass-shell with a nucleosynthetic code, with increases (decreases) by a factor of ten on the rates of 1196 nuclear reactions. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. For selected reactions, we have recomputed the nucleosynthesis with alternative prescriptions for their rates taken from the JINA REACLIB database, and have analyzed the temperature ranges where modifications of their rates have the strongest effect on nucleosynthesis. The nucleosynthesis resulting from the Type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of 12C nuclei. The energy of the explosion changes by less than \\sim4%. The changes in the nucleosynthesis due to the modification of the rates of fusion reactions are as well quite modest, for instance no species with a mass fraction larger than 0.02 experiences a variation of its yield larger than a factor of two. We provide the sensitivity of the yields of the most abundant species with respect to the rates of the most intense reactions with protons, neutrons, and alphas. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the charged particle reactions, the most influential on supernova nucleosynthesis are 30Si + p \\rightleftarrows 31P + {\\gamma}, 20Ne + {\\alpha} \\rightleftarrows 24Mg + {\\gamma}, and 24Mg + {\\alpha} \\rightleftarrows 27Al + p. The temperatures at which a modification of their rate has a larger impact are in the range 2 < T < 4 GK. (abridged)

  3. Neutrino-induced nucleosynthesis of A>64 nuclei: The nu p-process

    E-Print Network [OSTI]

    C. Fröhlich; G. Martínez-Pinedo; M. Liebendörfer; F. -K. Thielemann; E. Bravo; W. R. Hix; K. Langanke; N. T. Zinner

    2005-11-12T23:59:59.000Z

    We present a new nucleosynthesis process, that we denote nu p-process, which occurs in supernovae (and possibly gamma-ray bursts) when strong neutrino fluxes create proton-rich ejecta. In this process, antineutrino absorptions in the proton-rich environment produce neutrons that are immediately captured by neutron-deficient nuclei. This allows for the nucleosynthesis of nuclei with mass numbers A >64. Making this process a possible candidate to explain the origin of the solar abundances of 92,94Mo and 96,98Ru. This process also offers a natural explanation for the large abundance of Sr seen in an hyper-metal-poor star.

  4. Axion cold dark matter in nonstandard cosmologies

    SciTech Connect (OSTI)

    Visinelli, Luca; Gondolo, Paolo [Department of Physics and Astronomy, University of Utah, 115 South 1400 East 201, Salt Lake City, Utah 84112-0830 (United States)

    2010-03-15T23:59:59.000Z

    We study the parameter space of cold dark matter axions in two cosmological scenarios with nonstandard thermal histories before big bang nucleosynthesis: the low-temperature reheating (LTR) cosmology and the kination cosmology. If the Peccei-Quinn symmetry breaks during inflation, we find more allowed parameter space in the LTR cosmology than in the standard cosmology and less in the kination cosmology. On the contrary, if the Peccei-Quinn symmetry breaks after inflation, the Peccei-Quinn scale is orders of magnitude higher than standard in the LTR cosmology and lower in the kination cosmology. We show that the axion velocity dispersion may be used to distinguish some of these nonstandard cosmologies. Thus, axion cold dark matter may be a good probe of the history of the Universe before big bang nucleosynthesis.

  5. Cosmological Cosmic Rays: Sharpening the Primordial Lithium Problem

    E-Print Network [OSTI]

    Tijana Prodanovic; Brian D. Fields

    2007-09-20T23:59:59.000Z

    Cosmic structure formation leads to large-scale shocked baryonic flows which are expected to produce a cosmological population of structure-formation cosmic rays (SFCRs). Interactions between SFCRs and ambient baryons will produce lithium isotopes via \\alpha+\\alpha \\to ^{6,7}Li. This pre-Galactic (but non-primordial) lithium should contribute to the primordial 7Li measured in halo stars and must be subtracted in order to arrive to the true observed primordial lithium abundance. In this paper we point out that the recent halo star 6Li measurements can be used to place a strong constraint to the level of such contamination, because the exclusive astrophysical production of 6Li is from cosmic-ray interactions. We find that the putative 6Li plateau, if due to pre-Galactic cosmic-ray interactions, implies that SFCR-produced lithium represents Li_{SFCR}/Li_{plateau}\\approx 15% of the observed elemental Li plateau. Taking the remaining plateau Li to be cosmological 7Li, we find a revised (and slightly worsened) discrepancy between the Li observations and Big Bang Nucleosynthesis predictions by a factor of ^7Li_{BBN}/^7Li_{plateau} \\approx 3.7. Moreover, SFCRs would also contribute to the extragalactic gamma-ray background (EGRB) through neutral pion production. This gamma-ray production is tightly related to the amount of lithium produced by the same cosmic rays; the 6Li plateau limits the pre-Galactic (high-redshift) SFCR contribution to be at the level of I_{\\pi_{\\gamma}SFCR}/I_{EGRB} < 5% of the currently observed EGRB.

  6. {beta}-delayed neutron decay in {sup 17}B and {sup 19}C

    SciTech Connect (OSTI)

    Raimann, G. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Ozawa, A. [The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-01 (Japan); Boyd, R.N. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)]|[Department of Astronomy, The Ohio State University, Columbus, Ohio 43210 (United States); Chloupek, F.R. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Fujimaki, M. [The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-01 (Japan); Kimura, K. [Nagasaki Institute of Applied Science, Nagasaki, Nagasaki 851-01 (Japan); Kobayashi, T. [The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-01 (Japan); Kolata, J.J. [Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Kubono, S. [Institute of Nuclear Study, University of Tokyo, Tanashi, Tokyo 188 (Japan); Tanihata, I.; Watanabe, Y.; Yoshida, K. [The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-01 (Japan)

    1995-02-05T23:59:59.000Z

    The {beta}-delayed neutron decays of {sup 17}B and {sup 19}C were studied using radioactive ion beams. The neutron energies, measured via time-of-flight, give information on states above the neutron decay threshold in {sup 17}C and {sup 19}N, respectively. These low lying states are of possible interest for Big Bang nucleosynthesis. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  7. Effects of neutrino oscillations on nucleosynthesis and neutrino signals for an 18 M supernova model

    E-Print Network [OSTI]

    Wu, Meng-Ru; Martinez-Pinedo, Gabriel; Fischer, Tobias; Huther, Lutz

    2014-01-01T23:59:59.000Z

    In this paper, we explore the effects of neutrino flavor oscillations on supernova nucleosynthesis and on the neutrino signals. Our study is based on detailed information about the neutrino spectra and their time evolution from a spherically-symmetric supernova model for an 18 M progenitor. We find that collective neutrino oscillations are not only sensitive to the detailed neutrino energy and angular distributions at emission, but also to the time evolution of both the neutrino spectra and the electron density profile. We apply the results of neutrino oscillations to study the impact on supernova nucleosynthesis and on the neutrino signals from a Galactic supernova. We show that in our supernova model, collective neutrino oscillations enhance the production of rare isotopes 138La and 180Ta but have little impact on the nu p-process nucleosynthesis. In addition, the adiabatic MSW flavor transformation, which occurs in the C/O and He shells of the supernova, may affect the production of light nuclei such as 7L...

  8. Nucleosynthesis in Fast Expansions of High-Entropy, Proton Rich Matter

    E-Print Network [OSTI]

    G. C. Jordan IV; B. S. Meyer

    2004-06-29T23:59:59.000Z

    We demonstrate that nucleosynthesis in rapid, high-entropy expansions of proton-rich matter from high temperature and density can result in a wider variety of abundance patterns than heretofore appreciated. In particular, such expansions can produce iron-group nuclides, p-process nuclei, or even heavy, neutron-rich isotopes. Such diversity arises because the nucleosynthesis enters a little explored regime in which the free nucleons are not in equilibrium with the abundant alpha particles. This allows nuclei significantly heavier than iron to form in t he presence of abundant free nucleons early in the expansion. As the temperature drops, nucleons increasingly assemble into alpha particles and heavier nuclei. If the assembly is efficient, the resulting depletion of free neutrons allows disintegrat ion flows to drive nuclei back down to iron and nickel. If this assembly is inefficient, then the large abundance of free nucleons prevents the disintegration flows and leaves a distribution of heavy nuclei after reaction freezeout. For cases in between, an intermediate abundance distribution, enriched in p-process isotopes, is frozen out. These last expansions may contribute to the solar system's supply of the p-process nuclides if mildly proton-rich, high-entropy matter is ejected from proto-neutron stars winds or other astrophysical sites. Also sign ificant is the fact that, because the nucleosynthesis is primary, the signature of this nucleosyn thesis may be evident in metal poor stars.

  9. The Karlsruhe Astrophysical Database of Nucleosynthesis in Stars Project - Status and Prospects

    E-Print Network [OSTI]

    Iris Dillmann; Tamas Szücs; Zsolt Fülöp; Ralf Plag; Franz Käppeler; Thomas Rauscher

    2014-08-16T23:59:59.000Z

    The KADoNiS (Karlsruhe Astrophysical Database of Nucleosynthesis in Stars) project is an astrophysical online database for cross sections relevant for nucleosynthesis in the $s$ process and the $\\gamma$ process. The $s$-process database (www.kadonis.org) was started in 2005 and is presently facing its 4th update (KADoNiS v1.0). The $\\gamma$-process database (KADoNiS-p, www.kadonis.org/pprocess) was recently revised and re-launched in March 2013. Both databases are compilations for experimental cross sections with relevance to heavy ion nucleosynthesis. For the $s$ process recommended Maxwellian averaged cross sections for $kT$= 5-100~keV are given for more than 360 isotopes between $^{1}$H and $^{210}$Bi. For the $\\gamma$-process database all available experimental data from $(p,\\gamma), (p,n), (p,\\alpha), (\\alpha,\\gamma), (\\alpha,n)$, and $(\\alpha,p)$ reactions between $^{70}$Ge and $^{209}$Bi in or close to the respective Gamow window were collected and can be compared to theoretical predictions. The aim of both databases is a quick and user-friendly access to the available data in the astrophysically relevant energy regions.

  10. R-Process Nucleosynthesis in Dynamically Ejected Matter of Neutron Star Mergers

    E-Print Network [OSTI]

    Stephane Goriely; Andreas Bauswein; H. -Thomas Janka

    2011-08-09T23:59:59.000Z

    Although the rapid neutron-capture process, or r-process, is fundamentally important for explaining the origin of approximately half of the stable nuclei with A > 60, the astrophysical site of this process has not been identified yet. Here we study r-process nucleosynthesis in material that is dynamically ejected by tidal and pressure forces during the merging of binary neutron stars (NSs) and within milliseconds afterwards. For the first time we make use of relativistic hydrodynamical simulations of such events, defining consistently the conditions that determine the nucleosynthesis, i.e., neutron enrichment, entropy, early density evolution and thus expansion timescale, and ejecta mass. We find that 10^{-3}-10^{-2} solar masses are ejected, which is enough for mergers to be the main source of heavy (A > 140) galactic r-nuclei for merger rates of some 10^{-5} per year. While asymmetric mergers eject 2-3 times more mass than symmetric ones, the exact amount depends weakly on whether the NSs have radii of ~15 km for a "stiff" nuclear equation of state (EOS) or ~12 km for a "soft" EOS. R-process nucleosynthesis during the decompression becomes largely insensitive to the detailed conditions because of efficient fission recycling, producing a composition that closely follows the solar r-abundance distribution for nuclei with mass numbers A > 140. Estimating the light curve powered by the radioactive decay heating of r-process nuclei with an approximative model, we expect high emission in the B-V-R bands for 1-2 days with potentially observable longer duration in the case of asymmetric mergers because of the larger ejecta mass.

  11. Nucleosynthesis in the outflows associated with accretion disks of Type II collapsars

    E-Print Network [OSTI]

    Indrani Banerjee; Banibrata Mukhopadhyay

    2013-09-04T23:59:59.000Z

    We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially and a mild supernova explosion is driven. The supernova ejecta lack momentum and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks has been studied extensively in the past. Several heavy elements are synthesized in the disk and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this we find that many new elements like isotopes of titanium, copper, zinc etc. are present in the outflows. 56Ni is abundantly synthesized in most of the cases in the outflow which implies that the outflows from these disks in a majority of cases will lead to an observable supernova explosion. It is mainly present when outflow is considered from the He-rich, 56Ni/54Fe rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although, emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton etc., Swift seems to have not detected these lines yet.

  12. NUCLEOSYNTHESIS IN THE OUTFLOWS ASSOCIATED WITH ACCRETION DISKS OF TYPE II COLLAPSARS

    SciTech Connect (OSTI)

    Banerjee, Indrani; Mukhopadhyay, Banibrata, E-mail: indrani@physics.iisc.ernet.in, E-mail: bm@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India)

    2013-11-20T23:59:59.000Z

    We investigate nucleosynthesis inside the outflows from gamma-ray burst (GRB) accretion disks formed by the Type II collapsars. In these collapsars, massive stars undergo core collapse to form a proto-neutron star initially, and a mild supernova (SN) explosion is driven. The SN ejecta lack momentum, and subsequently this newly formed neutron star gets transformed to a stellar mass black hole via massive fallback. The hydrodynamics and the nucleosynthesis in these accretion disks have been studied extensively in the past. Several heavy elements are synthesized in the disk, and much of these heavy elements are ejected from the disk via winds and outflows. We study nucleosynthesis in the outflows launched from these disks by using an adiabatic, spherically expanding outflow model, to understand which of these elements thus synthesized in the disk survive in the outflow. While studying this, we find that many new elements like isotopes of titanium, copper, zinc, etc., are present in the outflows. {sup 56}Ni is abundantly synthesized in most of the cases in the outflow, which implies that the outflows from these disks in a majority of cases will lead to an observable SN explosion. It is mainly present when outflow is considered from the He-rich, {sup 56}Ni/{sup 54}Fe-rich zones of the disks. However, outflow from the Si-rich zone of the disk remains rich in silicon. Although emission lines of many of these heavy elements have been observed in the X-ray afterglows of several GRBs by Chandra, BeppoSAX, XMM-Newton, etc., Swift seems to have not yet detected these lines.

  13. Low-mass helium star models for type Ib supernovae - Light curves, mixing, and nucleosynthesis

    SciTech Connect (OSTI)

    Shigeyama, Toshikazu; Nomoto, Kenichi; Tsujimoto, Takuji; Hashimoto, Masaki (Tokyo Univ. (Japan) Kyushu Univ., Fukuoka (Japan))

    1990-09-01T23:59:59.000Z

    The applicability of theoretical models of He-star explosions to type Ib SN explosions is explored. Particular attention is given to light curves and mixing, Rayleigh-Taylor instabilities and mixing, and nucleosynthesis and the mass of Ni-56. Typical numerical results are presented in graphs, and it is concluded that the explosions of SN 1983N and SN 1983I can be accurately represented in terms of explosions of He stars with M(alpha) of 3-4 solar mass. A strong M(alpha) dependence of light-curve shape, photospheric velocity, and Ni-56 mass is found. 44 refs.

  14. On the introduction of {sup 17}O+p reaction rates evaluated through the THM in AGB nucleosynthesis calculations

    SciTech Connect (OSTI)

    Palmerini, S.; Sergi, M. L.; La Cognata, M.; Pizzone, R. G. [I.N.F.N. Laboratori Nazionali del Sud, via Santa Sofia 62, Catania (Italy); Lamia, L.; Spitaleri, C. [Dipartimento di Fisica e Astronomia, Universitá degli Studi di Catania (Italy)

    2014-05-09T23:59:59.000Z

    The rates for the {sup 17}O(p,??{sup 14}N, {sup 17}O(p,?){sup 18}F and {sup 18}O(p,?){sup 15}N reactions deduced trough the Trojan Horse Method (THM) have been introduced into a state-of-the-art asymptotic giant branch (AGB) models for proton-capture nucleosynthesis and cool bottom process. The predicted abundances have been compared with isotopic compositions provided by geochemical analysis of presolar grains. As a result, an improved agreement is found between the models and the isotopic mix of oxide grains of AGB origins, whose composition is the signature of low-temperature proton-capture nucleosynthesis.

  15. Inverse Problems 15 (1999) 329341. Printed in the UK PII: S0266-5611(99)97635-9 Bigger uncertainties and the Big Bang

    E-Print Network [OSTI]

    Lineweaver, Charles H.

    and energy in the Universe. Evidence of this heterogeneity is the non-zero quadrupole term in the CMB, or on modelling the effect of unestimated high-frequency terms, without accounting for model uncertainty Background Explorer (COBE), carrying the Differential Microwave Radiometer (DMR) instrument on 0266

  16. Determination of Dark Energy and Dark Matter from the values of Redshift for the present time, Planck and Trans-Planck epochs of the Big-Bang model

    E-Print Network [OSTI]

    Asger G. Gasanalizade; Ramin A. Hasanalizade

    2015-02-20T23:59:59.000Z

    As an alternative to the Standard cosmology model we have developed a new modified Freundlich's (quantum relativity) redshift (MFRS) mechanisms, which provide a precise solutions of the Dark Energy and Dark Matter problems. We apply the joint solution of three MFRS equations for concordances quantize bounce Planck hierarchy steps. Simultaneous scaling solutions of MFRS equations in logarithmic scale appropriate to three cosmological epoch's, yields a currently testable predictions regarding the Dark Matter {\\Omega}_{DM} = 0.25, and Dark Energy {\\Omega}_{DE} = 0.75. These predictions coincides with the recent observational data from WMAP and other a key supernovae SNe Ia findings. Thus, the presence of Dark Matter and Dark Energy had already been not only detected observationally, but also confirmed theoretically with the very compelling accuracy. From the WMAP7 and our predicted ages we find a value of the Hubble constant H_0 = 65.6 km * s^{-1} Mpc^{-1} which is excellent agreement with the Planck 2013 results XVI. Compared with the "holographic scenario" results, we find an important coincidence between our new and "holographic" parameters. We discuss the connection hierarchy between the multiverse masses and examine the status of the cosmic acceleration. The product of the age of the Universe into the cosmic acceleration in each cosmological epochs --including present day are constant and precisely corresponds to an possible observable-geophysical parameter g_U = 9.50005264_{265} (exact) * (m/s^2). For the derived by WMAP7 age of the Universe t_{W7} = 13.75(13) * 10^9 yr, we find the relevant acceleration a_{W7} = 6.91(65) * 10^{-10} m/s^2. The predicted value of t_0 = 9.0264_9(51) * 10^2 Gyr is consistent with the background acceleration. a_0 = 1.05246_4(61) * 10^{-11} m/s^2.

  17. Aspherical nucleosynthesis in a core-collapse supernova with 25 M {sub ?} standard progenitor

    SciTech Connect (OSTI)

    Popov, M. V. [École Normale Supérieure de Lyon, CRAL (UMR CNRS 5574), Université de Lyon 1, 46 allée d'Italie, F-69007 Lyon (France); Filina, A. A.; Baranov, A. A.; Chardonnet, P. [LAPTh, Université de Savoie, 9, Chemin de Bellevue BP 110, F-74941 Annecy-le-Vieux Cedex (France); Chechetkin, V. M. [Keldysh Institute of Applied Mathematics RAS, Miusskaya sq. 4, 125047 Moscow (Russian Federation)

    2014-03-01T23:59:59.000Z

    The problem of nucleosynthesis was studied within an aspherical supernova model. The explosive burning was computed in a star of 25 M {sub ?} initial mass on its final stage of evolution. The chemical composition of a presupernova was taken from realistic evolutionary computations. A piecewise parabolic method on a local stencil was applied to simulate the hydrodynamics of the explosion. The gravity was recomputed by a Poisson solver on a fine grid as the explosion developed. A detailed yield of chemical elements was performed as a post-processing step using the tracer particles method. The produced nuclei formed a layer-like structure enclosing large fragments of nickel and iron-group isotopes that were pushed away from the central region by an explosion along the polar direction. The light nuclei were preferentially moving along the equatorial plane forming a torus-like structure.

  18. Beta-decay spectroscopy relevant to the r-process nucleosynthesis

    SciTech Connect (OSTI)

    Nishimura, Shunji [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Collaboration: RIBF Decay Collaboration

    2012-11-12T23:59:59.000Z

    A scientific program of beta-decay spectroscopy relevant to r-process nucleosynthesis has been started using high intensity U-beam at the RIBF. The first results of {beta}-decay half-lives of very neutron-rich Kr to Tc nuclides, all of which lie close to the r-process path, suggest a systematic enhancement of the the {beta}-decay rates of the Zr and Nb isotopes around A110 with respect to the predictions of the deformed quasiparticle-random-phase-approximation model (FRDM + QRPA). An impact of the results on the astrophysical r-process is discussed together with the future perspective of the {beta}-decay spectroscopy with the EURICA.

  19. The neutrino-induced neutron source in helium shell and r-process nucleosynthesis

    E-Print Network [OSTI]

    D. K. Nadyozhin; I. V. Panov; S. I. Blinnikov

    1998-07-06T23:59:59.000Z

    The huge neutrino pulse that occurs during the collapse of a massive stellar core, is expected to contribute to the origination of a number of isotopes both of light chemical elements and heavy ones. It is shown that, in general, the heating of stellar matter due to the neutrino scattering off electrons and the heat released from the neutrino-helium breakup followed by the thermonuclear reactions should be taken into account. On the base of kinetic network, using all the important reactions up to Z=8, the main features and the time-dependent character of the neutrino- driven neutron flux are investigated. The time-dependent densities of free neutrons produced in helium breakup, Y_n(t), were used to calculate the r-process nucleosynthesis with another full kinetic network for 3200 nuclides. It was found that in the case of metal-deficient stars, Z neutrons seems to be high enough to drive the r-process efficiently under favorable conditions. But it is impossible to obtain a sufficient amount of heavy nuclei in neutrino-induced r-process in a helium shell at radii R > R_cr \\approx 10^9 cm. We speculate that to make the neutrino-induced r-process work efficiently in the shell, one has to invoke nonstandard presupernova models in which helium hopefully is closer to the collapsed core owing, for instance, to a large scale mixing or/and rotation and magnetic fields. Apart from this exotic possibility, the neutrino-induced nucleosynthesis in the helium shell is certainly not strong enough to explain the observed solar r-process abundances.

  20. s-Process Nucleosynthesis in Advanced Burning Phases of Massive Stars

    E-Print Network [OSTI]

    Lih-Sin The; Mounib F. El Eid; Bradley S. Meyer

    2006-09-28T23:59:59.000Z

    We present a detailed study of s-process nucleosynthesis in massive stars of solar-like initial composition and masses 15, 20,25, and 30 Msun. We update our previous results of s-process nucleosynthesis during the core He-burning of these stars and then focus on an analysis of the s-process under the physical conditions encountered during the shell-carbon burning. We show that the recent compilation of the Ne22(alpha,n)Mg25 rate leads to a remarkable reduction of the efficiency of the s-process during core He-burning. In particular, this rate leads to the lowest overproduction factor of Kr80 found to date during core He-burning in massive stars. The s-process yields resulting from shell carbon burning turn out to be very sensitive to the structural evolution of the carbon shell. This structure is influenced by the mass fraction of C12 attained at the end of core helium burning, which in turn is mainly determined by the C12(alpha,gamma)O16 reaction. The still present uncertainty in the rate for this reaction implies that the s-process in massive stars is also subject to this uncertainty. We identify some isotopes like Zn70 and Rb87 as the signatures of the s-process during shell carbon burning in massive stars. In determining the relative contribution of our s-only stellar yields to the solar abundances, we find it is important to take into account the neutron exposure of shell carbon burning. When we analyze our yields with a Salpeter Initial Mass Function, we find that massive stars contribute at least 40% to s-only nuclei with mass A 90, massive stars contribute on average ~7%, except for Gd152, Os187, and Hg198 which are ~14%, \\~13%, and ~11%, respectively.

  1. THE IMPACT OF HELIUM-BURNING REACTION RATES ON MASSIVE STAR EVOLUTION AND NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    West, Christopher; Heger, Alexander [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Austin, Sam M., E-mail: west0482@umn.edu, E-mail: alexander.heger@monash.edu, E-mail: austin@nscl.msu.edu [Joint Institute for Nuclear Astrophysics, Notre Dame, IN 46556 (United States)

    2013-05-20T23:59:59.000Z

    We study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the helium-burning reaction rates within the range of their uncertainties. The current solar abundances from Lodders are used for the initial stellar composition. We compute a grid of 12 initial stellar masses and 176 models per stellar mass to explore the effects of independently varying the {sup 12}C({alpha}, {gamma}){sup 16}O and 3{alpha} reaction rates, denoted R{sub {alpha},12} and R{sub 3{alpha}}, respectively. The production factors of both the intermediate-mass elements (A = 16-40) and the s-only isotopes along the weak s-process path ({sup 70}Ge, {sup 76}Se, {sup 80}Kr, {sup 82}Kr, {sup 86}Sr, and {sup 87}Sr) were found to be in reasonable agreement with predictions for variations of R{sub 3{alpha}} and R{sub {alpha},12} of {+-}25%; the s-only isotopes, however, tend to favor higher values of R{sub 3{alpha}} than the intermediate-mass isotopes. The experimental uncertainty (one standard deviation) in R{sub 3{alpha}}(R{sub {alpha},12}) is approximately {+-}10%({+-}25%). The results show that a more accurate measurement of one of these rates would decrease the uncertainty in the other as inferred from the present calculations. We also observe sharp changes in production factors and standard deviations for small changes in the reaction rates, due to differences in the convection structure of the star. The compactness parameter was used to assess which models would likely explode as successful supernovae, and hence contribute explosive nucleosynthesis yields. We also provide the approximate remnant masses for each model and the carbon mass fractions at the end of core-helium burning as a key parameter for later evolution stages.

  2. Impact of neutrino flavor oscillations on the neutrino-driven wind nucleosynthesis of an electron-capture supernova

    E-Print Network [OSTI]

    Pllumbi, Else; Wanajo, Shinya; Janka, H -Thomas; Huedepohl, Lorenz

    2014-01-01T23:59:59.000Z

    Neutrino oscillations, especially to light sterile states, can affect the nucleosynthesis yields because of their possible feedback effect on the electron fraction (Ye). For the first time, we perform nucleosynthesis calculations for neutrino-driven wind trajectories from the neutrino-cooling phase of an 8.8 Msun electron-capture supernova, whose hydrodynamic evolution was computed in spherical symmetry with sophisticated neutrino transport and whose Ye evolution was post-processed by including neutrino oscillations both between active and active-sterile flavors. We also take into account the alpha-effect as well as weak magnetism and recoil corrections in the neutrino absorption and emission processes. We observe effects on the Ye evolution which depend in a subtle way on the relative radial positions of the sterile MSW resonances, of collective flavor transformations, and on the formation of alpha-particles. For the adopted supernova progenitor, we find that neutrino oscillations, also to a sterile state wi...

  3. Lowest l=0 proton resonance in {sup 26}Si and implications for nucleosynthesis of {sup 26}Al

    SciTech Connect (OSTI)

    Peplowski, P. N.; Baby, L. T.; Wiedenhoever, I.; Diffenderfer, E.; Hoeflich, P.; Rojas, A.; Volya, A. [Physics Department, Florida State University, Tallahassee, Florida 32306 (United States); Dekat, S. E.; Gay, D. L. [Department of Chemistry and Physics, University of North Florida, Jacksonville, Florida 32224 (United States); Grubor-Urosevic, O. [Department of Chemistry and Physics, Purdue University Calumet, Hammond, Indiana 46323 (United States); Kaye, R. A. [Department of Chemistry and Physics, Purdue University Calumet, Hammond, Indiana 46323 (United States); Department of Physics and Astronomy, Ohio Wesleyan University, Delaware, Ohio 43015 (United States); Keeley, N. [Department of Nuclear Reactions, Andrezj Soltan Institute for Nuclear Studies, PL-00681 Warsaw (Poland)

    2009-03-15T23:59:59.000Z

    Using a beam of the radioactive isotope {sup 25}Al, produced with the new RESOLUT facility, we measured the direct (d,n) proton-transfer reaction leading to low-lying proton resonances in {sup 26}Si. We observed the lowest l=0 proton resonance, identified with the 3{sup +} state at 5.914-MeV excitation energy. This result eliminates the largest uncertainty in astrophysical reaction rates involved in the nucleosynthesis of {sup 26}Al.

  4. The Effects of Variations in Nuclear Interactions on Nucleosynthesis in Thermonuclear Supernovae

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Ivo R. Seitenzahl; Friedrich K. Roepke

    2013-06-25T23:59:59.000Z

    The impact of nuclear physics uncertainties on nucleosynthesis in thermonuclear supernovae has not been fully explored using comprehensive and systematic studies with multiple models. To better constrain predictions of yields from these phenomena, we have performed a sensitivity study by post-processing thermodynamic histories from two different hydrodynamic, Chandrasekhar-mass explosion models. We have individually varied all input reaction and, for the first time, weak interaction rates by a factor of ten and compared the yields in each case to yields using standard rates. Of the 2305 nuclear reactions in our network, we find that the rates of only 53 reactions affect the yield of any species with an abundance of at least 10^-8 M_sun by at least a factor of two, in either model. The rates of the 12C(a,g), 12C+12C, 20Ne(a,p), 20Ne(a,g) and 30Si(p,g) reactions are among those that modify the most yields when varied by a factor of ten. From the individual variation of 658 weak interaction rates in our network by a factor of ten, only the stellar 28Si(b+)28Al, 32S(b+)32P and 36Ar(b+)36Cl rates significantly affect the yields of species in a model. Additional tests reveal that reaction rate changes over temperatures T > 1.5 GK have the greatest impact, and that ratios of radionuclides that may be used as explosion diagnostics change by a factor of less than two from the variation of individual rates by a factor of 10. Nucleosynthesis in the two adopted models is relatively robust to variations in individual nuclear reaction and weak interaction rates. Laboratory measurements of a limited number of reactions would help to further constrain predictions. As well, we confirm the need for a consistent treatment for relevant stellar weak interaction rates since simultaneous variation of these rates (as opposed to individual variation) has a significant effect on yields in our models.

  5. Explosive nucleosynthesis: nuclear physics impact using neutrino-driven wind simulations

    E-Print Network [OSTI]

    A. Arcones; G. Martinez-Pinedo

    2010-12-14T23:59:59.000Z

    We present nucleosynthesis studies based on hydrodynamical simulations of core-collapse supernovae and their subsequent neutrino-driven winds. Although the conditions found in these simulations are not suitable for the rapid neutron capture (r-process) to produce elements heavier than A$\\sim$130, this can be solved by artificially increasing the wind entropy. In this way one can mimic the general behavior of an ejecta where the r-process occurs. We study the impact of the long-time dynamical evolution and of the nuclear physics input on the final abundances and show that different nuclear mass models lead to significant variations in the abundances. These differences can be linked to the behavior of nuclear masses far from stability. In addition, we have analyzed in detail the effect of neutron capture and beta-delayed neutron emission when matter decays back to stability. In all our studied cases, freeze out effects are larger than previously estimated and produce substantial changes in the post freeze out abundances.

  6. A New Study of s-Process Nucleosynthesis in Massive Stars

    E-Print Network [OSTI]

    L. -S. The; M. F. El Eid; B. S. Meyer

    1998-12-11T23:59:59.000Z

    We present a comprehensive study of s-process nucleosynthesis in 15, 20, 25, and 30 $\\msun$ stellar models having solar-like initial composition. The stars are evolved up to ignition of central neon with a 659 species network coupled to the stellar models. In this way, the initial composition from one burning phase to another is consistently determined, especially with respect to neutron capture reactions. The aim of our calculations is to gain a full account of the s-process yield from massive stars. In the present work, we focus primarily on the s-process during central helium burning and illuminate some major uncertainties affecting the calculations. We briefly show how advanced burning can significantly affect the products of the core helium burning s-process and, in particular, can greatly deplete $^{80}$Kr that was strongly overproduced in the earlier core helium burning phase; however, we leave a complete analysis of the s-process during the advanced evolutionary phases (especially in shell carbon burning) to a subsequent paper. Our results can help to constrain the yield of the s-process material from massive stars during their pre-supernova evolution.

  7. Nucleosynthesis and mixing on the Asymptotic Giant Branch. III. Predicted and observed s-process abundances

    E-Print Network [OSTI]

    M. Busso; R. Gallino; D. L. Lambert; C. Travaglio; V. V. Smith

    2001-04-26T23:59:59.000Z

    We present the results of s-process nucleosynthesis calculations for AGB stars of different metallicities and initial masses. The computations were based on previously published stellar evolutionary models that account for the III dredge up phenomenon occurring late on the AGB. Neutron production is driven by the 13C(alpha,n)16O reaction during the interpulse periods in a tiny layer in radiative equilibrium at the top of the He- and C-rich shell. The s-enriched material is subsequently mixed with the envelope by the III dredge up, and the envelope composition is computed after each thermal pulse. We follow the changes in the photospheric abundance of the Ba-peak elements (heavy s, or `hs') and that of the Zr-peak ones (light s, or `ls'), whose logarithmic ratio [hs/ls] has often been adopted as an indicator of the s-process efficiency. The theoretical predictions are compared with published abundances of s elements for Galactic AGB giants of classes MS, S, SC, post-AGB supergiants, and for various classes of binary stars. The observations in general confirm the complex dependence of n captures on metallicity. They suggest that a moderate spread exists in the abundance of 13C that is burnt in different stars. Although additional observations are needed, a good understanding has been achieved of s-process operation in AGB. The detailed abundance distribution including the light elements (CNO) of a few s-enriched stars at different metallicity are examined.

  8. Effects of the Gravitino on the Inflationary Universe

    E-Print Network [OSTI]

    Takeo Moroi

    1995-03-02T23:59:59.000Z

    Gravitino problem is discussed in detail. We derive an upperbound on the reheating temperature from the constraints of the big-bang nucleosynthesis and the present mass density of the universe. Compared to previous works, we have improve the following three points; (i) the gravitino production cross sections are calculated by taking all the relevant terms in the supergravity lagrangian into account, (ii) high energy photon spectrum is obtained by solving the Boltzmann equations numerically, and (iii) the evolutions of the light elements (D, T, $^3$He, $^4$He) at the temperature lower than $\\sim$1MeV are calculated by using modified Kawano's computer code.

  9. Can mirror matter solve the the cosmological lithium problem?

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS/IN2P3, Université Paris Sud 11, UMR 8609, Bâtiment 104, 91405 Orsay Campus (France); Uzan, Jean-Philippe; Vangioni, Elisabeth [Institut d'Astrophysique de Paris, UMR-7095 du CNRS, Université Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris, France and Sorbonne Universités, Institut Lagrange de Paris, 98 bis bd Arago, 75014 Paris (France)

    2014-05-02T23:59:59.000Z

    The abundance of lithium-7 confronts cosmology with a long lasting inconsistency between the predictions of standard Big Bang Nucleosynthesis with the baryonic density determined from the Cosmic Microwave Background observations on the one hand, and the spectroscopic determination of the lithium-7 abundance on the other hand. We investigated the influence of the existence of a mirror world, focusing on models in which mirror neutrons can oscillate into ordinary neutrons. Such a mechanism allows for an effective late time neutron injection, which induces an increase of the destruction of beryllium-7and thus a lower final lithium-7 abundance.

  10. Axion Constraints in Non-standard Thermal Histories

    SciTech Connect (OSTI)

    Grin, Daniel; Smith, Tristan; Kamionkowski, Marc [California Institute of Technology, Mail Code 130-33, Pasadena, CA 91125 (United States)

    2009-09-08T23:59:59.000Z

    There is no direct evidence for radiation domination prior to big-bang nucleosynthesis, and so it is useful to consider how constraints to thermally-produced axions change in non-standard thermal histories. In the low-temperature-reheating scenario, radiation domination begins as late as {approx}1 MeV, and is preceded by significant entropy generation. Axion abundances are then suppressed, and cosmological limits to axions are significantly loosened. In a kination scenario, a more modest change to axion constraints occurs. Future possible constraints to axions and low-temperature reheating are discussed.

  11. Thermal axion constraints in non-standard thermal histories

    SciTech Connect (OSTI)

    Grin, Daniel; Smith, Tristan; Kamionkowski, Marc [California Institute of Technology, Mail Code 130-33, Pasadena, CA 91125 (United States)

    2010-08-30T23:59:59.000Z

    There is no direct evidence for radiation domination prior to big-bang nucleosynthesis, and so it is useful to consider how constraints to thermally-produced axions change in non-standard thermal histories. In the low-temperature-reheating scenario, radiation domination begins as late as {approx}1 MeV, and is preceded by significant entropy generation. Axion abundances are then suppressed, and cosmological limits to axions are significantly loosened. In a kination scenario, a more modest change to axion constraints occurs. Future possible constraints to axions and low-temperature reheating are discussed.

  12. Thermal axion constraints in non-standard thermal histories

    E-Print Network [OSTI]

    Daniel Grin; Tristan Smith; Marc Kamionkowski

    2009-11-10T23:59:59.000Z

    There is no direct evidence for radiation domination prior to big-bang nucleosynthesis, and so it is useful to consider how constraints to thermally-produced axions change in non-standard thermal histories. In the low-temperature-reheating scenario, radiation domination begins at temperatures as low as 1 MeV, and is preceded by significant entropy generation. Axion abundances are then suppressed, and cosmological limits to axions are significantly loosened. In a kination scenario, a more modest change to axion constraints occurs. Future possible constraints to axions and low-temperature reheating are discussed.

  13. Thermal relics in cosmology with bulk viscosity

    E-Print Network [OSTI]

    A. Iorio; G. Lambiase

    2014-11-28T23:59:59.000Z

    In this paper we discuss some consequences of cosmological models in which the primordial cosmic matter is described by a relativistic imperfect fluid. The latter takes into account the dissipative effects (bulk viscosity) arising from different cooling rates of the fluid components in the expanding Universe. We discuss, in particular, the effects of the bulk viscosity on Big Bang Nucleosynthesis and on the thermal relic abundance of particles, looking at recent results of PAMELA experiment. The latter has determined an anomalous excess of positron events, that cannot be explained by the conventional cosmology and particle physics.

  14. Photon-neutrino interaction in theta-exact covariant noncommutative field theory

    E-Print Network [OSTI]

    R. Horvat; D. Kekez; P. Schupp; J. Trampetic; J. You

    2011-08-04T23:59:59.000Z

    Photon-neutrino interactions arise quite naturally in noncommutative field theories. Such couplings are absent in ordinary field theory and imply experimental lower bounds on the energy scale Lambda_NC ~ 1/|theta|^2 of noncommutativity. Using non-perturbative methods and a Seiberg-Witten map based covariant approach to noncommutative gauge theory, we obtain theta-exact expressions for the interactions, thereby eliminating previous restrictions to low-energy phenomena. We discuss implications for plasmon decay, neutrino charge radii, big bang nucleosynthesis and ultrahigh energy cosmic rays. Our results behave reasonably throughout all interaction energy scales, thus facilitating further phenomenological applications.

  15. New Nuclear Reaction Flow during r-Process Nucleosynthesis in Supernovae: Critical Role of Light Neutron-Rich Nuclei

    E-Print Network [OSTI]

    M. Terasawa; K. Sumiyoshi; T. Kajino; G. J. Mathews; I. Tanihata

    2001-07-19T23:59:59.000Z

    We study the role of light neutron-rich nuclei during r-process nucleosynthesis in supernovae. Most previous studies of the r-process have concentrated on the reaction flow of heavy unstable nuclei. Although the nuclear reaction network includes a few thousand heavy nuclei, only limited reaction flow through light-mass nuclei near the stability line has been used in those studies. However, in a viable scenario of the r-process in neutrino-driven winds, the initial condition is a high-entropy hot plasma consisting of neutrons, protons, and electron-positron pairs experiencing an intense flux of neutrinos. In such environments light-mass nuclei as well as heavy nuclei are expected to play important roles in the production of seed nuclei and r-process elements. Thus, we have extended our fully implicit nuclear reaction network so that it includes all nuclei up to the neutron drip line for Z $ \\leq 10$, in addition to a larger network for Z $ \\geq 10$. In the present nucleosynthesis study, we utilize a wind model of massive SNeII explosions to study the effects of this extended network. We find that a new nuclear-reaction flow path opens in the very light neutron-rich region. This new nuclear reaction flow can change the final heavy-element abundances by as much as an order of magnitude.

  16. New neutron capture and total cross section measurements on {sup 88}Sr and their impact on s-process nucleosynthesis

    SciTech Connect (OSTI)

    Koehler, P.E.; Spencer, R.R.; Guber, K.H. [and others

    1998-11-01T23:59:59.000Z

    The authors have made new and improved measurements of the neutron capture and total cross sections of {sup 88}Sr at the Oak Ridge Electron Linear Accelerator (ORELA). Improvements over previous measurements include a wider incident neutron energy range, the use of metallic rather than carbonate samples, better background subtraction, reduced sensitivity to sample-dependent backgrounds, and better pulse-height weighting functions. Because of its small cross section, the {sup 88}Sr(n,{gamma}) reaction is an important bottleneck during the s-process nucleosynthesis. Hence, an accurate determination of this rate is needed to better constrain the neutron exposure in s-process models and to more fully exploit the recently discovered isotopic anomalies in certain meteorites. They describe the experimental procedures, compare the results to previous data, and discuss their astrophysical impact.

  17. The Sensitivity of Nucleosynthesis in Type I X-ray Bursts to Thermonuclear Reaction-Rate Variations

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

    2008-06-18T23:59:59.000Z

    We examine the sensitivity of nucleosynthesis in Type I X-ray bursts to variations in nuclear rates. As a large number of nuclear processes are involved in these phenomena -with the vast majority of reaction rates only determined theoretically due to the lack of any experimental information- our results can provide a means for determining which rates play significant roles in the thermonuclear runaway. These results may then motivate new experiments. For our studies, we have performed a comprehensive series of one-zone post-processing calculations in conjunction with various representative X-ray burst thermodynamic histories. We present those reactions whose rate variations have the largest effects on yields in our studies.

  18. Impact of neutrino flavor oscillations on the neutrino-driven wind nucleosynthesis of an electron-capture supernova

    E-Print Network [OSTI]

    Else Pllumbi; Irene Tamborra; Shinya Wanajo; H. -Thomas Janka; Lorenz Huedepohl

    2014-06-11T23:59:59.000Z

    Neutrino oscillations, especially to light sterile states, can affect the nucleosynthesis yields because of their possible feedback effect on the electron fraction (Ye). For the first time, we perform nucleosynthesis calculations for neutrino-driven wind trajectories from the neutrino-cooling phase of an 8.8 Msun electron-capture supernova, whose hydrodynamic evolution was computed in spherical symmetry with sophisticated neutrino transport and whose Ye evolution was post-processed by including neutrino oscillations both between active and active-sterile flavors. We also take into account the alpha-effect as well as weak magnetism and recoil corrections in the neutrino absorption and emission processes. We observe effects on the Ye evolution which depend in a subtle way on the relative radial positions of the sterile MSW resonances, of collective flavor transformations, and on the formation of alpha-particles. For the adopted supernova progenitor, we find that neutrino oscillations, also to a sterile state with eV-mass, do not significantly affect the element formation and in particular cannot make the post-explosion wind outflow neutron rich enough to activate a strong r-process. Our conclusions become even more robust when, in order to mimic equation-of-state dependent corrections due to nucleon potential effects in the dense-medium neutrino opacities, four cases with reduced Ye in the wind are considered. In these cases, despite the conversion of neutrinos to sterile neutrinos, Ye increases compared to the values obtained without oscillations and active flavor transformations. This is a consequence of a complicated interplay between sterile-neutrino production, neutrino-neutrino interactions, alpha-effect.

  19. Leptogenesis in Inflationary Universe

    E-Print Network [OSTI]

    T. Asaka; K. Hamaguchi; M. Kawasaki; T. Yanagida

    1999-07-30T23:59:59.000Z

    We investigate the leptogenesis via decays of heavy Majorana neutrinos which are produced non-thermally in inflaton decays. We make a comprehensive study on the leptogenesis assuming various supersymmetric (SUSY) models for hybrid, new and topological inflations. For an estimation of the lepton asymmetry we adopt the Froggatt-Nielsen mechanism for mass matrices of quarks and leptons. We find that all of these models are successful to produce the lepton asymmetry enough to explain the baryon number in the present universe. Here we impose low reheating temperatures such as $T_R \\lesssim 10^8$ GeV in order to suppress the abundance of gravitinos not to conflict with the big-bang nucleosynthesis. Furthermore, we find that the leptogenesis works very well even with $T_R \\simeq 10^{6}$ GeV in the SUSY hybrid or new inflation model. It is known that such a reheating temperature is low enough to suppress the abundance of gravitinos of mass $m_{3/2} \\simeq 100$ GeV--1 TeV. Thus, the leptogenesis is fully consistent with the big-bang nucleosynthesis in a wide region of the gravitino mass.

  20. Falk Herwig: Mixing and Nucleosynthesis in IMS 16 Sep 2004 Cat'sEyeNebula,APOD4Sep02,Corradi&Goncalves

    E-Print Network [OSTI]

    Herwig, Falk

    & Lattanzio(partly published, 2003, PASA) Ventura etal (2002) A&A, 393 Herwig (2004), ApJS,155, #12;Falk: Ventura etal 2002 H04: Herwig 2004 average X in ejecta Ventura etal 2002 vs Herwig 2004 #12;Falk Herwig: »Mixing and Nucleosynthesis in IMS« 16 Sep 2004 Ventura etal 2002 vs Herwig 2004 4 He 12 C H04 H04 V02 V02

  1. Helium and Deuterium Abundances as a Test for the Time Variation of the Fine Structure Constant and the Higgs Vacuum Expectation Value

    E-Print Network [OSTI]

    Nidal Chamoun; Susana J. Landau; Mercedes E. Mosquera; Hector Vucetich

    2006-12-21T23:59:59.000Z

    We use the semi-analytic method of \\citet{Esma91} to calculate the abundances of Helium and Deuterium produced during Big Bang nucleosynthesis assuming the fine structure constant and the Higgs vacuum expectation value may vary in time. We analyze the dependence on the fundamental constants of the nucleon mass, nuclear binding energies and cross sections involved in the calculation of the abundances. Unlike previous works, we do not assume the chiral limit of QCD. Rather, we take into account the quark masses and consider the one-pion exchange potential, within perturbation theory, for the proton-neutron scattering. However, we do not consider the time variation of the strong interactions scale but attribute the changes in the quark masses to the temporal variation of the Higgs vacuum expectation value. Using the observational data of the helium and deuterium, we put constraints on the variation of the fundamental constants between the time of nucleosynthesis and the present time.

  2. NITROGEN ISOTOPES IN ASYMPTOTIC GIANT BRANCH CARBON STARS AND PRESOLAR SiC GRAINS: A CHALLENGE FOR STELLAR NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    Hedrosa, R. P.; Abia, C.; Dominguez, I.; Palmerini, S. [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, E-18071 Granada (Spain); Busso, M. [Dipartimento di Fisica, Universita di Perugia, I-06123 Perugia (Italy); Cristallo, S.; Straniero, O. [INAF, Osservatorio di Collurania, I-64100 Teramo (Italy); Plez, B. [Laboratoire Univers et Particules de Montpellier, Universite Montpellier II, CNRS, F-34095 Montpellier (France)

    2013-05-01T23:59:59.000Z

    Isotopic ratios of C, N, Si, and trace heavy elements in presolar SiC grains from meteorites provide crucial constraints to nucleosynthesis. A long-debated issue is the origin of the so-called A+B grains, as of yet no stellar progenitor thus far has been clearly identified on observational grounds. We report the first spectroscopic measurements of {sup 14}N/{sup 15}N ratios in Galactic carbon stars of different spectral types and show that J- and some SC-type stars might produce A+B grains, even for {sup 15}N enrichments previously attributed to novae. We also show that most mainstream grains are compatible with the composition of N-type stars, but in some cases might also descend from SC stars. From a theoretical point of view, no astrophysical scenario can explain the C and N isotopic ratios of SC-, J-, and N-type carbon stars together, as well as those of many grains produced by them. This poses urgent questions to stellar physics.

  3. Volume 5 Number 2 February 14, 2004 THE UNIVERSITY OF HONG KONG

    E-Print Network [OSTI]

    Tam, Vincent W. L.

    ), the big bang (the first moments of the universe), gamma ray bursts (the biggest explosions in the universe

  4. 64-esimo Corso di Orientamento Universitario Scuola Normale Superiore

    E-Print Network [OSTI]

    Abbondandolo, Alberto

    ;1. Si "ricreano le condizioni del big bang" Dalla termodinamica del "forno cosmico": =(T) t=t(T) Dalla

  5. Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. I. Detailed analysis of 15 binary stars with known orbital periods

    E-Print Network [OSTI]

    Abate, C; Karakas, A I; Izzard, R G

    2015-01-01T23:59:59.000Z

    AGB stars are responsible for producing a variety of elements, including carbon, nitrogen, and the heavy elements produced in the slow neutron-capture process ($s$-elements). There are many uncertainties involved in modelling the evolution and nucleosynthesis of AGB stars, and this is especially the case at low metallicity, where most of the stars with high enough masses to enter the AGB have evolved to become white dwarfs and can no longer be observed. The stellar population in the Galactic halo is of low mass ($\\lesssim 0.85M_{\\odot}$) and only a few observed stars have evolved beyond the first giant branch. However, we have evidence that low-metallicity AGB stars in binary systems have interacted with their low-mass secondary companions in the past. The aim of this work is to investigate AGB nucleosynthesis at low metallicity by studying the surface abundances of chemically peculiar very metal-poor stars of the halo observed in binary systems. To this end we select a sample of 15 carbon- and $s$-element-en...

  6. Active-Sterile neutrino oscillations and BBN+CMBR constraints

    E-Print Network [OSTI]

    P. Di Bari; R. Foot

    2000-11-13T23:59:59.000Z

    We show how active-sterile neutrino oscillations in the early Universe can play an interesting role in explaining the current observations of CMBR anisotropies and light element abundances. We describe different possible phenomenological scenarios in the interpretation of present data and how active-sterile neutrino oscillations can provide a viable theoretical framework.

  7. Neutrino Masses in Astroparticle Physics

    E-Print Network [OSTI]

    G. G. Raffelt

    2002-08-08T23:59:59.000Z

    The case for small neutrino mass differences from atmospheric and solar neutrino oscillation experiments has become compelling, but leaves the overall neutrino mass scale m_nu undetermined. The most restrictive limit of m_nu neutrinos. If solar neutrino oscillations indeed correspond to the favored large mixing angle MSW solution, then big-bang nucleosynthesis gives us a restrictive limit on all neutrino chemical potentials, removing the previous uncertainty of n_nu. Therefore, a possible future measurement of m_nu will directly establish the cosmic neutrino mass fraction Omega_nu. Cosmological neutrinos with sub-eV masses can play an interesting role for producing the highest-energy cosmic rays (Z-burst scenario). Sub-eV masses also relate naturally to leptogenesis scenarios of the cosmic baryon asymmetry. Unfortunately, the time-of-flight dispersion of a galactic or local-group supernova neutrino burst is not sensitive in the sub-eV range.

  8. Blue-tilted Tensor Spectrum and Thermal History of the Universe

    E-Print Network [OSTI]

    Sachiko Kuroyanagi; Tomo Takahashi; Shuichiro Yokoyama

    2014-07-17T23:59:59.000Z

    We investigate constraints on the spectral index of primordial gravitational waves (GWs), paying particular attention to a blue-tilted spectrum. Such constraints can be used to test a certain class of models of the early Universe. We investigate observational bounds from LIGO+Virgo, pulsar timing and big bang nucleosynthesis, taking into account the suppression of the amplitude at high frequencies due to reheating after inflation and also late-time entropy production. Constraints on the spectral index are presented by changing values of parameters such as reheating temperatures and the amount of entropy produced at late time. We also consider constraints under the general modeling approach which can approximately describe various scenarios of the early Universe. We show that the constraints on the blue spectral tilt strongly depend on the underlying assumption and, in some cases, a highly blue-tilted spectrum can still be allowed.

  9. Laser-interferometric Detectors for Gravitational Wave Background at 100 MHz : Detector Design and Sensitivity

    E-Print Network [OSTI]

    Atsushi Nishizawa; Seiji Kawamura; Tomotada Akutsu; Koji Arai; Kazuhiro Yamamoto; Daisuke Tatsumi; Erina Nishida; Masa-aki Sakagami; Takeshi Chiba; Ryuichi Takahashi; Naoshi Sugiyama

    2008-01-30T23:59:59.000Z

    Recently, observational searches for gravitational wave background (GWB) have developed and given direct and indirect constraints on the energy density of GWB in a broad range of frequencies. These constraints have already rejected some theoretical models of large GWB spectra. However, at 100 MHz, there is no strict upper limit from direct observation, though the indirect limit by He4 abundance due to big-bang nucleosynthesis exists. In this paper, we propose an experiment with laser interferometers searching GWB at 100 MHz. We considered three detector designs and evaluated the GW response functions of a single detector. As a result, we found that, at 100 MHz, the most sensitive detector is the design, a so-called synchronous recycling interferometer, which has better sensitivity than an ordinary Fabry-Perot Michelson interferometer by a factor of 3.3 at 100 MHz. We also give the best sensitivity achievable at 100 MHz with realistic experimental parameters.

  10. The 3He(alpha,gamma)7Be S-factor at solar energies: the prompt gamma experiment at LUNA

    E-Print Network [OSTI]

    H. Costantini; D. Bemmerer; F. Confortola; A. Formicola; Gy. Gyürky; P. Bezzon; R. Bonetti; C. Broggini; P. Corvisiero; Z. Elekes; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; G. Imbriani; M. Junker; M. Laubenstein; A. Lemut; B. Limata; V. Lozza; M. Marta; R. Menegazzo; P. Prati; V. Roca; C. Rolfs; C. Rossi Alvarez; E. Somorjai; O. Straniero; F. Strieder; F. Terrasi; H. P. Trautvetter

    2008-09-30T23:59:59.000Z

    The 3He(alpha,gamma)7Be process is a key reaction in both Big-Bang nucleosynthesis and p-p chain of Hydrogen Burning in Stars. A new measurement of the 3He(alpha,gamma)7Be cross section has been performed at the INFN Gran Sasso underground laboratory by both the activation and the prompt gamma detection methods. The present work reports full details of the prompt gamma detection experiment, focusing on the determination of the systematic uncertainty. The final data, including activation measurements at LUNA, are compared with the results of the last generation experiments and two different theoretical models are used to obtain the S-factor at solar energies.

  11. The 14C(n,g) cross section between 10 keV and 1 MeV

    E-Print Network [OSTI]

    R. Reifarth; M. Heil; C. Forssen; U. Besserer; A. Couture; S. Dababneh; L. Doerr; J. Goerres; R. C. Haight; F. Kaeppeler; A. Mengoni; S. O'Brien; N. Patronis; R. Plag; R. S. Rundberg; M. Wiescher; J. B. Wilhelmy

    2009-10-01T23:59:59.000Z

    The neutron capture cross section of 14C is of relevance for several nucleosynthesis scenarios such as inhomogeneous Big Bang models, neutron induced CNO cycles, and neutrino driven wind models for the r process. The 14C(n,g) reaction is also important for the validation of the Coulomb dissociation method, where the (n,g) cross section can be indirectly obtained via the time-reversed process. So far, the example of 14C is the only case with neutrons where both, direct measurement and indirect Coulomb dissociation, have been applied. Unfortunately, the interpretation is obscured by discrepancies between several experiments and theory. Therefore, we report on new direct measurements of the 14C(n,g) reaction with neutron energies ranging from 20 to 800 keV.

  12. Spherically symmetric cosmological spacetimes with dust and radiation — numerical implementation

    SciTech Connect (OSTI)

    Lim, Woei Chet [Department of Mathematics, University of Waikato, Private Bag 3105, Hamilton 3240 (New Zealand); Regis, Marco [Dipartimento di Fisica, Università di Torino and INFN, Torino (Italy); Clarkson, Chris, E-mail: wclim@waikato.ac.nz, E-mail: regis@to.infn.it, E-mail: chris.clarkson@gmail.com [Astrophysics, Cosmology and Gravity Centre, and Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa)

    2013-10-01T23:59:59.000Z

    We present new numerical cosmological solutions of the Einstein Field Equations. The spacetime is spherically symmetric with a source of dust and radiation approximated as a perfect fluid. The dust and radiation are necessarily non-comoving due to the inhomogeneity of the spacetime. Such a model can be used to investigate non-linear general relativistic effects present during decoupling or big-bang nucleosynthesis, as well as for investigating void models of dark energy with isocurvature degrees of freedom. We describe the full evolution of the spacetime as well as the redshift and luminosity distance for a central observer. After demonstrating accuracy of the code, we consider a few example models, and demonstrate the sensitivity of the late time model to the degree of inhomogeneity of the initial radiation contrast.

  13. WMAPping out Neutrino Masses

    E-Print Network [OSTI]

    Aaron Pierce; Hitoshi Murayama

    2003-10-28T23:59:59.000Z

    Recent data from from the Wilkinson Microwave Anisotropy Probe (WMAP) place important bounds on the neutrino sector. The precise determination of the baryon number in the universe puts a strong constraint on the number of relativistic species during Big-Bang Nucleosynthesis. WMAP data, when combined with the 2dF Galaxy Redshift Survey (2dFGRS), also directly constrain the absolute mass scale of neutrinos. These results impinge upon a neutrino oscillation interpretation of the result from the Liquid Scintillator Neutrino Detector (LSND). We also note that the Heidelberg--Moscow evidence for neutrinoless double beta decay is only consistent with the WMAP+2dFGRS data for the largest values of the nuclear matrix element.

  14. Inflation, baryogenesis and gravitino dark matter at ultra low reheat temperatures

    E-Print Network [OSTI]

    Kazunori Kohri; Anupam Mazumdar; Narendra Sahu

    2009-05-11T23:59:59.000Z

    It is quite possible that the reheat temperature of the universe is extremely low close to the scale of Big Bang nucleosynthesis, i.e. $T_{R}\\sim 1-10$ MeV. At such low reheat temperatures generating matter anti-matter asymmetry and synthesizing dark matter particles are challenging issues which need to be addressed within a framework of beyond the Standard Model physics. In this paper we point out that a successful cosmology can emerge naturally provided the R-parity violating interactions are responsible for the excess in baryons over anti-baryons and at the same time they can explain the longevity of dark matter with the right abundance.

  15. Constraints upon the spectral indices of relic gravitational waves by LIGO S5

    SciTech Connect (OSTI)

    Zhang, Y.; Tong, M. L.; Fu, Z. W. [Key Laboratory for Researches in Galaxies Cosmology, CAS, Department of Astronomy, University of Science Technology of China, Hefei, Anhui, 230026 (China)

    2010-05-15T23:59:59.000Z

    With LIGO having achieved its design sensitivity and the LIGO S5 strain data being available, constraints on the relic gravitational waves (RGWs) become realistic. The analytical spectrum of RGWs generated during inflation depends sensitively on the initial condition, which is generically described by the index {beta}, the running index {alpha}{sub t}, and the tensor-to-scalar ratio r. By the LIGO S5 data of the cross-correlated two detectors, we obtain constraints on the parameters ({beta},{alpha}{sub t},r). As a main result, we have computed the theoretical signal-to-noise ratio of RGWs for various values of ({beta},{alpha}{sub t},r), using the cross-correlation for the given pair of LIGO detectors. The constraints by the indirect bound on the energy density of RGWs by big bang nucleosynthesis and cosmic microwave background have been obtained, which turn out to be still more stringent than LIGO S5.

  16. Cosmological Moduli and the Post-Inflationary Universe: A Critical Review

    E-Print Network [OSTI]

    Kane, Gordon; Watson, Scott

    2015-01-01T23:59:59.000Z

    We critically review the role of cosmological moduli in determining the post-inflationary history of the universe. Moduli are ubiquitous in string and M-theory constructions of beyond the Standard Model physics, where they parametrize the geometry of the compactification manifold. For those with masses determined by supersymmetry breaking this leads to their eventual decay slightly before Big Bang Nucleosynthesis (without spoiling its predictions). This results in a matter dominated phase shortly after inflation ends, which can influence baryon and dark matter genesis, as well as observations of the Cosmic Microwave Background and the growth of large-scale structure. Given progress within fundamental theory, and guidance from dark matter and collider experiments, non-thermal histories have emerged as a robust and theoretically well-motivated alternative to a strictly thermal one. We review this approach to the early universe and discuss both the theoretical challenges and the observational implications.

  17. Axion constraints in nonstandard thermal histories

    SciTech Connect (OSTI)

    Grin, Daniel; Smith, Tristan L.; Kamionkowski, Marc [California Institute of Technology, Mail Code 130-33, Pasadena, California 91125 (United States)

    2008-04-15T23:59:59.000Z

    It is usually assumed that dark matter is produced during the radiation-dominated era. There is, however, no direct evidence for radiation domination prior to big-bang nucleosynthesis. Two nonstandard thermal histories are considered. In one, the low-temperature-reheating scenario, radiation domination begins as late as {approx}1 MeV, and is preceded by significant entropy generation. Thermal axion relic abundances are then suppressed, and cosmological limits to axions are loosened. For reheating temperatures T{sub rh} < or approx. 35 MeV, the large-scale structure limit to the axion mass is lifted. The remaining constraint from the total density of matter is significantly relaxed. Constraints are also relaxed for higher reheating temperatures. In a kination scenario, a more modest change to cosmological axion constraints is obtained. Future possible constraints to axions and low-temperature reheating from the helium abundance and next-generation large-scale-structure surveys are discussed.

  18. WIMP Dark Matter Limit-Direct Detection Data and Sensitivity Plots from the Cryogenic Dark Matter Search II and the University of California at Santa Barbara

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Expectations for non-baryonic dark matter are founded principally in Big Bang nucleosynthesis calculations, which indicate that the missing mass of the universe is not likely to be baryonic. The supersymmetric standard model (SUSY) offers a promising framework for expectations of particle species which could satisfy the observed properties of dark matter. WIMPs are the most likely SUSY candidate for a dark matter particle. The High Energy Physics Group at University of California, Santa Barbara, is part of the CDMSII Collaboration and have provided the Interactive Plotter for WIMP Dark Matter Limit-Direct Detection Data on their website. They invite other collaborations working on dark matter research to submit datasets and, as a result, have more than 150 data sets now available for use with the plotting tool. The published source of the data is provided with each data set.

  19. Bimetric gravity is cosmologically viable

    E-Print Network [OSTI]

    Akrami, Yashar; Könnig, Frank; Schmidt-May, Angnis; Solomon, Adam R

    2015-01-01T23:59:59.000Z

    Bimetric theory describes gravitational interactions in the presence of an extra spin-2 field. Previous work has suggested that its cosmological solutions are generically plagued by instabilities. We show that by taking the Planck mass for the second metric, $M_f$, to be small, these instabilities can be pushed back to unobservably early times. In this limit, the theory approaches general relativity with an effective cosmological constant which is, remarkably, determined by the spin-2 interaction scale. This provides a late-time expansion history which is extremely close to $\\Lambda$CDM, but with a technically-natural value for the cosmological constant. We find $M_f$ should be no larger than the electroweak scale in order for cosmological perturbations to be stable by big-bang nucleosynthesis.

  20. Reaction rates of $^{64}$Ge($p,?$)$^{65}$As and $^{65}$As($p,?$)$^{66}$Se and the extent of nucleosynthesis in type I X-ray bursts

    E-Print Network [OSTI]

    Y. H. Lam; J. J. He; A. Parikh; B. A. Brown; M. Wang; B. Guo; Y. H. Zhang; X. H. Zhou; H. S. Xu

    2015-05-09T23:59:59.000Z

    The extent of nucleosynthesis in models of type I X-ray bursts and the associated impact on the energy released in these explosive events are sensitive to nuclear masses and reaction rates around the $^{64}$Ge waiting point. Using a recent high precision mass measurement of $^{65}$As along with large-scale shell model calculations, we have determined new thermonuclear rates of the $^{64}$Ge($p$,$\\gamma$)$^{65}$As and $^{65}$As($p$,$\\gamma$)$^{66}$Se reactions. We examine the impact of available rates for these two reactions through a representative one-zone X-ray burst model. We find that our recommended rates may strongly suppress the flow of abundances toward $A\\approx100$, in sharp contrast to recent work claiming that $^{64}$Ge is not a significant $rp$-process waiting point. Indeed, the summed mass fractions for species with $A > 70$ varies by about factors of 3 or 2 depending upon the adopted $^{64}$Ge($p$,$\\gamma$)$^{65}$As or $^{65}$As($p$,$\\gamma$)$^{66}$Se rates, respectively. Furthermore, the predictions for nuclear energy generation rate E$_\\mathrm{gen}$ at late times during the burst varies rather significantly between the models using the different rates, with differences as large as about a factor of 2.

  1. EXPLOSIVE NUCLEOSYNTHESIS IN THE NEUTRINO-DRIVEN ASPHERICAL SUPERNOVA EXPLOSION OF A NON-ROTATING 15 M{sub sun} STAR WITH SOLAR METALLICITY

    SciTech Connect (OSTI)

    Fujimoto, Shin-ichiro [Kumamoto National College of Technology, 2659-2 Suya, Goshi, Kumamoto 861-1102 (Japan); Kotake, Kei [Division of Theoretical Astronomy, National Astronomical Observatory Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Hashimoto, Masa-aki; Ono, Masaomi [Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Ohnishi, Naofumi, E-mail: fujimoto@ec.knct.ac.jp [Department of Aerospace Engineering, Tohoku University, 6-6-01 Aramaki-Aza-Aoba, Aoba-ku, Sendai 980-8579 (Japan)

    2011-09-01T23:59:59.000Z

    We investigate explosive nucleosynthesis in a non-rotating 15 M{sub sun} star with solar metallicity that explodes by a neutrino-heating supernova (SN) mechanism aided by both standing accretion shock instability (SASI) and convection. To trigger explosions in our two-dimensional hydrodynamic simulations, we approximate the neutrino transport with a simple light-bulb scheme and systematically change the neutrino fluxes emitted from the protoneutron star. By a post-processing calculation, we evaluate abundances and masses of the SN ejecta for nuclei with a mass number {<=}70, employing a large nuclear reaction network. Aspherical abundance distributions, which are observed in nearby core-collapse SN remnants, are obtained for the non-rotating spherically symmetric progenitor, due to the growth of a low-mode SASI. The abundance pattern of the SN ejecta is similar to that of the solar system for models whose masses range between (0.4-0.5) M{sub sun} of the ejecta from the inner region ({<=}10, 000 km) of the precollapse core. For the models, the explosion energies and the {sup 56}Ni masses are {approx_equal} 10{sup 51}erg and (0.05-0.06) M{sub sun}, respectively; their estimated baryonic masses of the neutron star are comparable to the ones observed in neutron-star binaries. These findings may have little uncertainty because most of the ejecta is composed of matter that is heated via the shock wave and has relatively definite abundances. The abundance ratios for Ne, Mg, Si, and Fe observed in the Cygnus loop are reproduced well with the SN ejecta from an inner region of the 15 M{sub sun} progenitor.

  2. Testing the Primary Origin of Be and B in the Early Galaxy

    E-Print Network [OSTI]

    Elisabeth Vangioni-Flam; Reuven Ramaty; Keith A. Olive; Michel Cassé

    1998-06-05T23:59:59.000Z

    Two types of models have been proposed to explain the linear rise of the Be and B abundances as a function of iron observed in metal poor halo stars. In both cases, this linearity indicates that freshly synthesized C and O are accelerated by Type II supernovae and subsequently fragmented into Be and B. One mechanism advocates shock acceleration in the gaseous phase of superbubbles excavated by collective SNII explosions. Because of their short lifetimes, only the most massive stars (with an initial mass greater than 60\\msun) do not drift out of superbubbles, and participate in BeB production. The second mechanism is based on the acceleration of the debris of grains formed in the ejecta of all SNIIs (originating from stars with initial mass greater than 8\\msun). Here again, fresh C and O are sped up to cosmic ray energies by shocks. We propose a possible test to discriminate between the two scenarios. If supernovae of all masses are involved in BeB production, the Be/Fe ratio is constant, since both elements are produced in the same events. Alternatively, when only the most massive stars are involved in Be production, Be/Fe is enhanced at very early times because of the shorter lifetimes of these stars. This predicted difference in the behavior of Be/Fe could be tested by high quality observations at [Fe/H] $\\lsim -3$. We also note that the solution invoking only the most massive supernovae mimics a flat evolution of both Be/H and B/H as a function of Fe/H at low metallicity, and could thus resemble a "plateau" for these elements despite a lack of a primordial Big Bang nucleosynthesis origin. Consequently, there may be no need to invoke inhomogeneous Big Bang models to explain the initial production of BeB should a plateau be discovered.

  3. Skimming the Profit Pool: The American Mutual Fund Scandals and the Risk for Japan

    E-Print Network [OSTI]

    Peterson, Andrew

    2010-01-01T23:59:59.000Z

    Investment trust . Deregulation The mutual fund industry isthe universe. In this case, deregulation of the financialof Britain’s Big Bang deregulation and followed suit, making

  4. Can We Observe Galaxies that Recede Faster than Light ? -- A More Clear-Cut Answer

    E-Print Network [OSTI]

    T. Kiang

    2003-05-27T23:59:59.000Z

    A more clear-cut answer to the title question is, ``Yes'' if the universal expansion started with a big bang; ``No'' if it started infinitely slowly.

  5. alternative dark energy: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    universe with the local Big Bang and everlasting expansion is demonstrated. Dark matter can be essentially contributed by the non-relativistic massive neutrinos, which have...

  6. THE NEW DETECTIONS OF {sup 7}Li/{sup 6}Li ISOTOPIC RATIO IN THE INTERSTELLAR MEDIA

    SciTech Connect (OSTI)

    Kawanomoto, S.; Kajino, T.; Aoki, W.; Ando, H.; Noguchi, K.; Tanaka, W. [National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Bessell, M. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, 2611 ACT (Australia); Suzuki, T. K. [Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro, Tokyo 153-8902 (Japan); Honda, S. [Gunma Astronomical Observatory, 6860-86 Nakayama Takayama-mura, Agatsuma-gun, Gunma 377-0702 (Japan); Izumiura, H.; Kambe, E.; Okita, K.; Watanabe, E.; Yoshida, M. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, 3037-5 Honjo, Kamogata, Asakuchi, Okayama 719-0232 (Japan); Sadakane, K. [Astronomical Institute, Osaka-Kyoiku University, Kashiwara-shi, Osaka 582-8582 (Japan); Sato, B. [Global Edge Institute Global Edge Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Tajitsu, A. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Takada-Hidai, M. [Liberal Arts Education Center, Tokai University 1117 Kitakaname, Hisatsuka-shi, Kanagawa 259-1292 (Japan)

    2009-08-20T23:59:59.000Z

    We have determined the isotopic abundance ratio of {sup 7}Li/{sup 6}Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed {zeta} Oph for comparison with previous data. The observed abundance ratios were {sup 7}Li/{sup 6}Li = 8.1{sup +3.6} {sub -1.8} and 6.3{sup +3.0} {sub -1.7} for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within {+-}2{sigma} error bars and are also consistent with our measurement of {sup 7}Li/{sup 6}Li = 7.1{sup +2.9} {sub -1.6} for a cloud along the line of sight to {zeta} Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of {sup 7}Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.

  7. Nuclear astrophysics: the unfinished quest for the origin of the elements

    E-Print Network [OSTI]

    Jordi Jose; Christian Iliadis

    2011-07-12T23:59:59.000Z

    Half a century has passed since the foundation of nuclear astrophysics. Since then, this discipline has reached its maturity. Today, nuclear astrophysics constitutes a multidisciplinary crucible of knowledge that combines the achievements in theoretical astrophysics, observational astronomy, cosmochemistry and nuclear physics. New tools and developments have revolutionized our understanding of the origin of the elements: supercomputers have provided astrophysicists with the required computational capabilities to study the evolution of stars in a multidimensional framework; the emergence of high-energy astrophysics with space-borne observatories has opened new windows to observe the Universe, from a novel panchromatic perspective; cosmochemists have isolated tiny pieces of stardust embedded in primitive meteorites, giving clues on the processes operating in stars as well as on the way matter condenses to form solids; and nuclear physicists have measured reactions near stellar energies, through the combined efforts using stable and radioactive ion beam facilities. This review provides comprehensive insight into the nuclear history of the Universe and related topics: starting from the Big Bang, when the ashes from the primordial explosion were transformed to hydrogen, helium, and few trace elements, to the rich variety of nucleosynthesis mechanisms and sites in the Universe. Particular attention is paid to the hydrostatic processes governing the evolution of low-mass stars, red giants and asymptotic giant-branch stars, as well as to the explosive nucleosynthesis occurring in core-collapse and thermonuclear supernovae, gamma-ray bursts, classical novae, X-ray bursts, superbursts, and stellar mergers.

  8. Kaluza-Klein relics from warped reheating

    SciTech Connect (OSTI)

    Berndsen, Aaron; Cline, James M.; Stoica, Horace [Physics Department, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada); Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

    2008-06-15T23:59:59.000Z

    It has been suggested that after brane-antibrane inflation in a Klebanov-Strassler (KS) warped throat, metastable Kaluza-Klein excitations can be formed due to nearly-conserved angular momenta along isometric directions in the throat. If sufficiently long lived, these relics could conflict with big bang nucleosynthesis or baryogenesis by dominating the energy density of the Universe. We make a detailed estimate of the decay rate of such relics using the low-energy effective action of type IIB string theory compactified on the throat geometry, with attention to powers of the warp factor. We find that it is necessary to turn on supersymmetry (SUSY)-breaking deformations of the KS background in order to ensure that the most dangerous relics will decay fast enough. The decay rate is found to be much larger than the naive guess based on the dimension of the operators which break the angular isometries of the throat. For an inflationary warp factor of order w{approx}10{sup -4}, we obtain the bound M{sub 3/2} > or approx. 10{sup 9} GeV on the scale of SUSY breaking to avoid cosmological problems from the relics, which is satisfied in the Kachru, Kallosh, Linde, and Trivedi construction assumed to stabilize the compactification. Given the requirement that the relics decay before nucleosynthesis or baryogenesis, we place bounds on the mass of the relic as a function of the warp factor in the throat for more general warped backgrounds.

  9. Reaction rates of $^{64}$Ge($p,\\gamma$)$^{65}$As and $^{65}$As($p,\\gamma$)$^{66}$Se and the extent of nucleosynthesis in type I X-ray bursts

    E-Print Network [OSTI]

    Lam, Y H; Parikh, A; Brown, B A; Wang, M; Guo, B; Zhang, Y H; Zhou, X H; Xu, H S

    2015-01-01T23:59:59.000Z

    The extent of nucleosynthesis in models of type I X-ray bursts and the associated impact on the energy released in these explosive events are sensitive to nuclear masses and reaction rates around the $^{64}$Ge waiting point. Using a recent high precision mass measurement of $^{65}$As along with large-scale shell model calculations, we have determined new thermonuclear rates of the $^{64}$Ge($p$,$\\gamma$)$^{65}$As and $^{65}$As($p$,$\\gamma$)$^{66}$Se reactions. We examine the impact of available rates for these two reactions through a representative one-zone X-ray burst model. We find that our recommended rates may strongly suppress the flow of abundances toward $A\\approx100$, in sharp contrast to recent work claiming that $^{64}$Ge is not a significant $rp$-process waiting point. Indeed, the summed mass fractions for species with $A > 70$ varies by about factors of 3 or 2 depending upon the adopted $^{64}$Ge($p$,$\\gamma$)$^{65}$As or $^{65}$As($p$,$\\gamma$)$^{66}$Se rates, respectively. Furthermore, the predi...

  10. A Secure Content Network in Space Craig Partridge

    E-Print Network [OSTI]

    Strayer, William Timothy

    A Secure Content Network in Space Craig Partridge Raytheon BBN Technologies craig@bbn.com Robert Walsh Raytheon BBN Technologies rwalsh@bbn.com Matthew Gillen Raytheon BBN Technologies mgillen@bbn.com Gregory Lauer Raytheon BBN Technologies glauer@bbn.com John Lowry Raytheon BBN Technologies jlowry

  11. A new determination of the primordial He abundance using the HeI 10830A emission line: cosmological implications

    E-Print Network [OSTI]

    Izotov, Y I; Guseva, N G

    2014-01-01T23:59:59.000Z

    We present near-infrared spectroscopic observations of the high-intensity HeI 10830 emission line in 45 low-metallicity HII regions. We combined these NIR data with spectroscopic data in the optical range to derive the primordial He abundance. The use of the HeI 10830A line, the intensity of which is very sensitive to the density of the HII region, greatly improves the determination of the physical conditions in the He^+ zone. This results in a considerably tighter Y - O/H linear regression compared to all previous studies. We extracted a final sample of 28 HII regions with Hbeta equivalent width EW(Hbeta)>150A, excitation parameter O^2+/O>0.8, and with helium mass fraction Y derived with an accuracy better than 3%. With this final sample we derived a primordial He mass fraction Yp = 0.2551+/-0.0022. The derived value of Yp is higher than the one predicted by the standard big bang nucleosynthesis (SBBN) model. Using our derived Yp together with D/H = (2.53+/-0.04)x10^-5, and the chi^2 technique, we found that...

  12. Nuclear Reactions from Lattice QCD

    E-Print Network [OSTI]

    Raúl A. Briceño; Zohreh Davoudi; Thomas C. Luu

    2014-11-25T23:59:59.000Z

    One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some of the low- energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path planned to move forward in the upcoming years.

  13. New measurement of the d(d,p)t reaction at astrophysical energies via the Trojan-horse method

    E-Print Network [OSTI]

    Chengbo Li; Qungang Wen; Yuanyong Fu; Jing Zhou; Shuhua Zhou; Qiuying Meng; C. Spitaleri; A. Tumino; R. G. Pizzone; L. Lamia

    2015-05-27T23:59:59.000Z

    The study of d(d,p)t reaction is very important for the nucleosynthesis in both standard Big Bang and stellar evolution, as well as for the future fusion reactors planning of energy production. The d(d,p)t bare nucleus astrophysical S(E) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan horse method applied to the quasi-free process $\\rm {}^2H({}^6Li,pt){}^4He$ induced at a lithium beam energy of 9.5 MeV, which is closer to the zero quasi-free energy point. An accurate analysis leads to the determination of the $\\rm S_{bare}(0)=56.7 \\pm 2.0 keV \\cdot b$ and of the corresponding electron screening potential $\\rm U_e = 13.2 \\pm 4.3 eV$. In addition, this work gives an updated test for the Trojan horse nucleus invariance comparing with previous indirect investigations using $\\rm {}^3He=(d+p)$ breakup.

  14. Nuclear reactions from lattice QCD

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Briceño, Raúl A.; Davoudi, Zohreh; Luu, Thomas C.

    2015-02-01T23:59:59.000Z

    One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some ofmore »the low-energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path planned to move forward in the upcoming years.« less

  15. Neutrinoless double-beta decay with three or four neutrino mixing

    E-Print Network [OSTI]

    C. Giunti

    1999-08-27T23:59:59.000Z

    Considering the scheme with mixing of three neutrinos and a mass hierarchy that can accommodate the results of solar and atmospheric neutrino experiments, it is shown that the results of solar neutrino experiments imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay, under the natural assumptions that massive neutrinos are Majorana particles and there are no unlikely fine-tuned cancellations among the contributions of the different neutrino masses. Considering the four-neutrino schemes that can accommodate also the results of the LSND experiment, it is shown that only one of them is compatible with the results of neutrinoless double-beta decay experiments and with the measurement of the abundances of primordial elements produced in Big-Bang Nucleosynthesis. It is shown that in this scheme, under the assumptions that massive neutrinos are Majorana particles and there are no cancellations among the contributions of the different neutrino masses, the results of the LSND experiment imply a lower bound for the effective Majorana mass in neutrinoless double-beta decay.

  16. Viscous dark fluid universe

    SciTech Connect (OSTI)

    Hipolito-Ricaldi, W. S. [Universidade Federal do Espirito Santo, Departamento de Ciencias Matematicas e Naturais, CEUNES, Rodovia BR 101 Norte, km. 60, CEP 29932-540, Sao Mateus, Espirito Santo (Brazil); Velten, H. E. S.; Zimdahl, W. [Universidade Federal do Espirito Santo, Departamento de Fisica, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitoria, Espirito Santo (Brazil)

    2010-09-15T23:59:59.000Z

    We investigate the cosmological perturbation dynamics for a universe consisting of pressureless baryonic matter and a viscous fluid, the latter representing a unified model of the dark sector. In the homogeneous and isotropic background the total energy density of this mixture behaves as a generalized Chaplygin gas. The perturbations of this energy density are intrinsically nonadiabatic and source relative entropy perturbations. The resulting baryonic matter power spectrum is shown to be compatible with the 2dFGRS and SDSS (DR7) data. A joint statistical analysis, using also Hubble-function and supernovae Ia data, shows that, different from other studies, there exists a maximum in the probability distribution for a negative present value q{sub 0{approx_equal}}-0.53 of the deceleration parameter. Moreover, while previous descriptions on the basis of generalized Chaplygin-gas models were incompatible with the matter power-spectrum data since they required a much too large amount of pressureless matter, the unified model presented here favors a matter content that is of the order of the baryonic matter abundance suggested by big-bang nucleosynthesis.

  17. Cosmic Data Fusion

    E-Print Network [OSTI]

    S. L. Bridle

    2000-12-22T23:59:59.000Z

    We compare and combine likelihood functions of the cosmological parameters Omega_m, h and sigma_8 from the CMB, type Ia supernovae and from probes of large scale structure. We include the recent results from the CMB experiments BOOMERANG and MAXIMA-1. Our analysis assumes a flat LambdaCDM cosmology with a scale-invariant adiabatic initial power spectrum. First we consider three data sets that directly probe the mass in the Universe, without the need to relate the galaxy distribution to the underlying mass via a `biasing' relation: peculiar velocities, CMB and supernovae. We assume a baryonic fraction as inferred from Big-Bang Nucleosynthesis and find that all three data sets agree well, overlapping significantly at the 2-sigma level. This therefore justifies a joint analysis, in which we find a joint best fit point and 95% confidence limits of Omega_m=0.28 (0.17,0.39), h=0.74 (0.64,0.86), and sigma_8=1.17 (0.98,1.37). Secondly we extend our earlier work on combining CMB, supernovae, cluster number counts, IRAS galaxy redshift survey data to include BOOMERANG and MAXIMA-1 data and to allow a free Omega_b h^2. We find that, given our assumption of a scale invariant initial power spectrum (n=1), we obtain the robust result of Omega_b h^2= 0.031 +/- 0.03, which is dominated by the CMB constraint.

  18. Machian gravity and a cosmology without dark matter and dark energy

    E-Print Network [OSTI]

    Santanu Das

    2015-04-10T23:59:59.000Z

    The standard model of cosmology is based on the general theory of relativity and demands more than 95\\% of the universe to consist of dark matter and dark energy that has no direct observational evidence till date. The foundation of the concept these dark components are based on a fixed relation between the strength of the gravitational field and the matter density. Alternate models are put forward in past to explain the observations without dark components in the universe. Though they have their own merits and draw backs. In this paper we propose a new cosmological model based on Mach's principle. It provides a similar cosmology as that of the standard cosmological model without any ad-hoc dark matter or dark energy. We show that the theory naturally provides some geometric terms that behave like dark mater and dark energy and dark radiation. The presence of dark radiation provides new observational features in cosmology. We show that the theory is supported by observational data from Big Bang Nucleosynthesis and Cosmic Microwave Background, and provides an explanations for excess number of effective neutrino species and higher Helium mass fraction in the universe. We also calculate the best fit cosmological parameters for our model using Planck+WP data.

  19. A Built-in Inflation in the $f(T)$-Cosmology

    E-Print Network [OSTI]

    G. G. L. Nashed; W. El Hanafy

    2014-10-24T23:59:59.000Z

    In the present work we derive an exact solution of an isotropic and homogeneous Universe governed by $f(T)$ gravity. We show how the torsion contribution to the FRW cosmology can provide a \\textit{unique} origin for both early and late acceleration phases of the Universe. The three models ($k=0, \\pm 1$) show a \\textit{built-in} inflationary behavior at some early Universe time; they restore suitable conditions for the hot big bang nucleosynthesis to begin. Unlike the standard cosmology, we show that even if the Universe initially started with positive or negative sectional curvatures, the curvature density parameter enforces evolution to a flat Universe. The solution constrains the torsion scalar $T$ to be a constant function at all time $t$, for the three models. This eliminates the need for the dark energy (DE). Moreover, when the continuity equation is assumed for the torsion fluid, we show that the flat and closed Universe models \\textit{violate} the conservation principle, while the open one does not. The evolution of the effective equation of state (EoS) of the torsion fluid implies a peculiar trace from a quintessence-like DE to a phantom-like one crossing a matter and radiation EoS in between; then it asymptotically approaches a de Sitter fate.

  20. New measurement of $\\rm S_{bare}(E)$ factor of the d(d,p)t reaction at astrophysical energies via the Trojan-horse method

    E-Print Network [OSTI]

    Li, Chengbo; Fu, Yuanyong; Zhou, Jing; Zhou, Shuhua; Meng, Qiuying; Spitaleri, C; Tumino, A; Pizzone, R G; Lamia, L

    2015-01-01T23:59:59.000Z

    The study of d(d,p)t reaction is very important for the nucleosynthesis in both standard Big Bang and stellar evolution, as well as for the future fusion reactor planning of energy production. The d(d,p)t bare nucleus astrophysical S(E) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan horse method applied to the quasi-free process $\\rm {}^2H({}^6Li,pt){}^4He$ induced at the lithium beam energy of 9.5 MeV, which is closer to the zero quasi-free energy point, in CIAE HI-13 tandem accelerator laboratory. An accurate analysis leads to the determination of the d(d,p)t $\\rm S(E)$ factor $\\rm S_{bare}(0)=56.7 \\pm 2.0 keV*b$ and of the corresponding electron screening potential $\\rm U_e = 13.2 \\pm 4.3 eV$. In addition, this work also gives an updated test for the Trojan horse nucleus invariance comparing with previous indirect investigations using $\\rm {}^3He=(d+p)$ breakup.

  1. New measurement of $\\rm S_{bare}(E)$ factor of the d(d,p)t reaction at astrophysical energies via the Trojan-horse method

    E-Print Network [OSTI]

    Chengbo Li; Qungang Wen; Yuanyong Fu; Jing Zhou; Shuhua Zhou; Qiuying Meng; C. Spitaleri; A. Tumino; R. G. Pizzone; L. Lamia

    2015-04-08T23:59:59.000Z

    The study of d(d,p)t reaction is very important for the nucleosynthesis in both standard Big Bang and stellar evolution, as well as for the future fusion reactor planning of energy production. The d(d,p)t bare nucleus astrophysical S(E) factor has been measured indirectly at energies from about 400 keV down to several keV by means of the Trojan horse method applied to the quasi-free process $\\rm {}^2H({}^6Li,pt){}^4He$ induced at the lithium beam energy of 9.5 MeV, which is closer to the zero quasi-free energy point, in CIAE HI-13 tandem accelerator laboratory. An accurate analysis leads to the determination of the d(d,p)t $\\rm S(E)$ factor $\\rm S_{bare}(0)=56.7 \\pm 2.0 keV*b$ and of the corresponding electron screening potential $\\rm U_e = 13.2 \\pm 4.3 eV$. In addition, this work also gives an updated test for the Trojan horse nucleus invariance comparing with previous indirect investigations using $\\rm {}^3He=(d+p)$ breakup.

  2. On the lithium dip in the metal poor open cluster NGC 2243

    SciTech Connect (OSTI)

    François, P. [GEPI, Paris-Meudon Observatory, 61 Avenue de l'Observatoire, F-75014 Paris (France); Pasquini, L.; Palsa, R. [ESO, European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München (Germany); Biazzo, K. [INAF, Capodimonte Astronomical Observatory, via Moiariello 16, 80131 Naples (Italy); Bonifacio, P. [GEPI, Paris-Meudon Observatory, Place Jules Janssen 92190, Meudon (France)

    2014-05-02T23:59:59.000Z

    Lithium is a key element for studying the mixing mechanisms operating in stellar interiors. It can also be used to probe the chemical evolution of the Galaxy and the Big Bang nucleosynthesis. Measuring the abundance of Lithium in stars belonging to Open Clusters (hereafter OC) allows a detailed comparison with stellar evolutionary models. NGC 2243 is particularly interesting thanks to its relative low metallicity ([Fe/H]=?0.54 ± 0.10 dex). We performed a detailed analysis of high-resolution spectra obtained with the multi-object facility FLAMES at the VLT 8.2m telescope. Lithium abundance has been measured in 27 stars. We found a Li dip center of 1.06 M{sub ?}, which is significantly smaller than that observed in solar metallicity and metal-rich clusters. This finding confirms and strengthens the conclusion that the mass of the stars in the Li dip strongly depends on stellar metallicity. The mean Li abundance of the cluster is log n(Li) = 2.70 dex, which is substantially higher than that observed in 47 Tue. We derived an iron abundance of [Fe/H]=?0.54±0.10 dex for NGC 2243, in agreement (within the errors) with previous findings.

  3. Axions and saxions from the primordial supersymmetric plasma and extra radiation signatures

    SciTech Connect (OSTI)

    Graf, Peter; Steffen, Frank Daniel, E-mail: graf@mpp.mpg.de, E-mail: steffen@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, D–80805 Munich (Germany)

    2013-02-01T23:59:59.000Z

    We calculate the rate for thermal production of axions and saxions via scattering of quarks, gluons, squarks, and gluinos in the primordial supersymmetric plasma. Systematic field theoretical methods such as hard thermal loop resummation are applied to obtain a finite result in a gauge-invariant way that is consistent to leading order in the strong gauge coupling. We calculate the thermally produced yield and the decoupling temperature for both axions and saxions. For the generic case in which saxion decays into axions are possible, the emitted axions can constitute extra radiation already prior to big bang nucleosynthesis and well thereafter. We update associated limits imposed by recent studies of the primordial helium-4 abundance and by precision cosmology of the cosmic microwave background and large scale structure. We show that the trend towards extra radiation seen in those studies can be explained by late decays of thermal saxions into axions and that upcoming Planck results will probe supersymmetric axion models with unprecedented sensitivity.

  4. Dark matter and cosmology

    SciTech Connect (OSTI)

    Schramm, D.N.

    1992-03-01T23:59:59.000Z

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  5. Dark matter and cosmology

    SciTech Connect (OSTI)

    Schramm, D.N.

    1992-03-01T23:59:59.000Z

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  6. Hidden MeV-scale dark matter in neutrino detectors

    SciTech Connect (OSTI)

    Kile, Jennifer; Soni, Amarjit [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2009-12-01T23:59:59.000Z

    The possibility of direct detection of light fermionic dark matter in neutrino detectors is explored from a model-independent standpoint. We consider all operators of dimension six or lower which can contribute to the interaction fp{yields}e{sup +}n, where f is a dark Majorana or Dirac fermion. Constraints on these operators are then obtained from the f lifetime and its decays which produce visible {gamma} rays or electrons. We find one operator which would allow fp{yields}e{sup +}n at interesting rates in neutrino detectors, as long as m{sub f} < or approx. m{sub {pi}}. The existing constraints on light dark matter from relic density arguments, supernova cooling rates, and big-bang nucleosynthesis are then reviewed. We calculate the cross section for fp{yields}e{sup +}n in neutrino detectors implied by this operator, and find that Super-Kamiokande can probe the new physics scale {lambda} for this interaction up to O(100 TeV)

  7. Hidden MeV-scale Dark Matter in Neutrino Detectors

    SciTech Connect (OSTI)

    Soni, A.; Kile, J

    2009-12-30T23:59:59.000Z

    The possibility of direct detection of light fermionic dark matter in neutrino detectors is explored from a model-independent standpoint. We consider all operators of dimension six or lower which can contribute to the interaction fp {yields} e{sup +}n, where f is a dark Majorana or Dirac fermion. Constraints on these operators are then obtained from the f lifetime and its decays which produce visible {gamma} rays or electrons. We find one operator which would allow fp {yields} e{sup +}n at interesting rates in neutrino detectors, as long as m{sub f} {approx}< m{sub {pi}}. The existing constraints on light dark matter from relic density arguments, supernova cooling rates, and big-bang nucleosynthesis are then reviewed. We calculate the cross section for fp {yields} e{sup +}n in neutrino detectors implied by this operator, and find that Super-Kamiokande can probe the new physics scale {Lambda} for this interaction up to O(100 TeV).

  8. Nuclear reactions from lattice QCD

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Briceno, Raul A. [JLAB; Davoudi, Zohreh; Luu, Thomas C.

    2015-02-01T23:59:59.000Z

    One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some of the low- energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path planned to move forward in the upcoming years.

  9. Explosive lithium production in the classical nova V339 Del (Nova Delphini 2013)

    E-Print Network [OSTI]

    Tajitsu, Akito; Naito, Hiroyuki; Arai, Akir; Aoki, Wako

    2015-01-01T23:59:59.000Z

    The origin of lithium (Li) and its production process have long been an unsettled question in cosmology and astrophysics. Candidates environments of Li production events or sites suggested by previous studies include big bang nucleosynthesis, interactions of energetic cosmic rays with interstellar matter, evolved low mass stars, novae, and supernova explosions. Chemical evolution models and observed stellar Li abundances suggest that at least half of the present Li abundance may have been produced in red giants, asymptotic giant branch (AGB) stars, and novae. However, no direct evidence for the supply of Li from stellar objects to the Galactic medium has yet been found. Here we report on the detection of highly blue-shifted resonance lines of the singly ionized radioactive isotope of beryllium, $^{7}$Be, in the near ultraviolet (UV) spectra of the classical nova V339 Del (Nova Delphini 2013). Spectra were obtained 38 to 48 days after the explosion. $^{7}$Be decays to form $^{7}$Li within a short time (half-li...

  10. Direct Search for Right-handed Neutrinos and Neutrinoless Double Beta Decay

    E-Print Network [OSTI]

    Takehiko Asaka; Shintaro Eijima

    2013-08-16T23:59:59.000Z

    We consider an extension of the Standard Model by two right-handed neutrinos, especially with masses lighter than charged $K$ meson. This simple model can realize the seesaw mechanism for neutrino masses and also the baryogenesis by flavor oscillations of right-handed neutrinos. We summarize the constraints on right-handed neutrinos from direct searches as well as the big bang nucleosynthesis. It is then found that the possible range for the quasi-degenerate mass of right-handed neutrinos is $M_N \\geq 163 \\MeV$ for normal hierarchy of neutrino masses, while $M_N = 188 \\text{--} 269 \\MeV$ and $M_N \\geq 285 \\MeV$ for inverted hierarchy case. Furthermore, we find in the latter case that the possible value of the Majorana phase is restricted for $M_N = 188 \\text{--} 350 \\MeV$, which leads to the fact that the rate of neutrinoless double beta decay is also limited.

  11. Primordial black holes from temporally enhanced curvature perturbation

    E-Print Network [OSTI]

    Teruaki Suyama; Yi-Peng Wu; Jun'ichi Yokoyama

    2014-06-02T23:59:59.000Z

    Scalar field with generalized kinetic interactions metamorphoses depending on its field value, ranging from cosmological constant to stiff matter. We show that such a scalar field can give rise to temporal enhancement of the curvature perturbation in the primordial Universe, leading to efficient production of primordial black holes while the enhancement persists. If the inflation energy scale is high, those mini-black holes evaporate by the Hawking radiation much before Big Bang nucleosynthesis and the effective reheating of the Universe is achieved by the black hole evaporation. Dominance of PBHs and the reheating by their evaporation modify the expansion history of the primordial Universe. This results in a characteristic feature of the spectrum of primordial tensor modes in the DECIGO frequency band, opening an interesting possibility of testing PBH reheating scenario by measuring the primordial tensor modes. If the inflation energy scale is low, the PBH mass can be much larger than the solar mass. In this case, PBH is an interesting candidate for seeds for supermassive black holes residing in present galaxies.

  12. Varying constants, Gravitation and Cosmology

    E-Print Network [OSTI]

    Jean-Philippe Uzan

    2010-09-28T23:59:59.000Z

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  13. K-mouflage Cosmology: the Background Evolution

    E-Print Network [OSTI]

    Philippe Brax; Patrick Valageas

    2014-11-30T23:59:59.000Z

    We study the cosmology of K-mouflage theories at the background level. We show that the effects of the scalar field are suppressed at high matter density in the early Universe and only play a role in the late time Universe where the deviations of the Hubble rate from its $\\Lambda$-CDM counterpart can be of the order five percent for redshifts $1 \\lesssim z \\lesssim 5$. Similarly, we find that the equation of state can cross the phantom divide in the recent past and even diverge when the effective scalar energy density goes negative and subdominant compared to matter, preserving the positivity of the squared Hubble rate. These features are present in models for which Big Bang Nucleosynthesis is not affected. We analyze the fate of K-mouflage when the nonlinear kinetic terms give rise to ghosts, particle excitations with negative energy. In this case, we find that the K-mouflage theories can only be considered as an effective description of the Universe at low energy below $1$ keV. In the safe ghost-free models, we find that the equation of state always diverges in the past and changes significantly by a few percent since $z\\lesssim 1$.

  14. Asymmetric condensed dark matter

    E-Print Network [OSTI]

    Aguirre, Anthony

    2015-01-01T23:59:59.000Z

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate can be very light, $10^{-22}\\,{\\rm eV} \\lesssim m \\lesssim 10^2\\,{\\rm eV}$; the lower limit arises from constraints on small-scale structure formation, while the upper bound ensures that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of deco...

  15. Radiative neutron capture on 9be, 14c, 14n, 15n and 16o at thermal and astrophysical energies

    E-Print Network [OSTI]

    Sergey Dubovichenko; Albert Dzhazairov-Kakhramanov; Nadezhda Afanasyeva

    2014-01-28T23:59:59.000Z

    The total cross sections of the radiative neutron capture processes on 9Be, 14C, 14N, 15N, and 16O are described in the framework of the modified potential cluster model with the classification of orbital states according to Young tableaux. The continued interest in the study of these reactions is due, on the one hand, to the important role played by this process in the analysis of many fundamental properties of nuclei and nuclear reactions, and, on the other hand, to the wide use of the capture cross section data in the various applications of nuclear physics and nuclear astrophysics, and, also, to the importance of the analysis of primordial nucleosynthesis in the Universe. This article is devoted to the description of results for the processes of the radiative neutron capture on certain light atomic nuclei at thermal and astrophysical energies. The considered capture reactions are not part of stellar thermonuclear cycles, but involve in the reaction chains of inhomogeneous Big Bang models.

  16. FansyRoute: Adaptive Fan-Out for Variably Intermittent Challenged Networks

    E-Print Network [OSTI]

    Ramanathan, Ram

    Raytheon BBN Technologies 10 Moulton Street, Cambridge, MA 02138 dabideen@bbn.com Ram Ramanathan Raytheon

  17. Abundance profiling of extremely metal-poor stars and supernova properties in the early universe

    SciTech Connect (OSTI)

    Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501 (Japan); Iwamoto, Nobuyuki [Nuclear Data Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Nomoto, Ken'ichi, E-mail: tominaga@konan-u.ac.jp, E-mail: iwamoto.nobuyuki@jaea.go.jp, E-mail: nomoto@astron.s.u-tokyo.ac.jp [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2014-04-20T23:59:59.000Z

    After the big bang nucleosynthesis, the first heavy element enrichment in the universe was made by a supernova (SN) explosion of a population (Pop) III star (Pop III SN). The abundance ratios of elements produced from Pop III SNe are recorded in abundance patterns of extremely metal-poor (EMP) stars. The observations of the increasing number of EMP stars have made it possible to statistically constrain the explosion properties of Pop III SNe. We present Pop III SN models whose nucleosynthesis yields well reproduce, individually, the abundance patterns of 48 such metal-poor stars as [Fe/H] ? – 3.5. We then derive relations between the abundance ratios of EMP stars and certain explosion properties of Pop III SNe: the higher [(C + N)/Fe] and [(C + N)/Mg] ratios correspond to the smaller ejected Fe mass and the larger compact remnant mass, respectively. Using these relations, the distributions of the abundance ratios of EMP stars are converted to those of the explosion properties of Pop III SNe. Such distributions are compared with those of the explosion properties of present day SNe: the distribution of the ejected Fe mass of Pop III SNe has the same peak as that of the present day SNe but shows an extended tail down to ?10{sup –2}-10{sup –5} M {sub ?}, and the distribution of the mass of the compact remnant of Pop III SNe is as wide as that of the present-day, stellar-mass black holes. Our results demonstrate the importance of large samples of EMP stars obtained by ongoing and future EMP star surveys and subsequent high-dispersion spectroscopic observations in clarifying the nature of Pop III SNe in the early universe.

  18. Advances in r-Process Nucleosynthesis

    E-Print Network [OSTI]

    John J. Cowan; Christopher Sneden

    2003-09-29T23:59:59.000Z

    During the last several decades, there have been a number of advances in understanding the rapid neutron-capture process (i.e., the r-process). These advances include large quantities of high-resolution spectroscopic abundance data of neutron-capture elements, improved astrophysical models, and increasingly more precise nuclear and atomic physics data. The elemental abundances of the heavy neutron-capture elements, from Ba through the third r-process peak, in low-metallicity ([Fe/H] = 56 the r-process is robust--appearing to operate in a relatively consistent manner over the history of the Galaxy--and place stringent constraints on r-process models. While not yet identified, neutron-rich ejecta outside of the core in a collapsing (Type II, Ib) supernova continues to be a promising site for the r-process. Neutron star binary mergers might also be a possible alternative site. Abundance comparisons of lighter n-capture elements in halo stars show variations with the scaled solar r-process curve and might suggest either multiple r-process sites, or, at least, different synthesis conditions in the same astrophysical site. Constraints on r-process models and clues to the progenitors of the halo stars--the earliest generations of Galactic stars--are also provided by the star-to-star abundance scatter of [Eu/Fe] at low metallicities in the early Galaxy. Finally, abundance observations of long-lived radioactive elements (such as Th and U) produced in the r-process can be used to determine the chronometric ages of the oldest stars, placing constraints on the lower limit age estimates of the Galaxy and the Universe.

  19. New abundances for old stars atomic diffusion at work in NGC 6397 A homogeneous spectroscopic analysis of unevolved and evolved stars in the metal-poor globular cluster NGC

    E-Print Network [OSTI]

    Korn, Andreas

    minutes after the Big Bang to stars as metal-rich as the Sun and beyond. The majority of this knowledge among warm halo stars by Monique and François Spite (1982; the so-called Spite plateau) and interpreted

  20. Fermilab Cultural Events in Chicago's Far West Side

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    for example, giant black holes gobbling up stars in the heart of quasars and gamma-ray bursts, which are the biggest explosions since the Big Bang. We will describe the...

  1. LIFE ON EARTH -- AN ACCIDENT? Chiral Symmetry and the Anthropic Principle

    E-Print Network [OSTI]

    Ulf-G. Meißner

    2013-12-29T23:59:59.000Z

    I discuss the fine-tuning of the nuclear forces and in the formation of nuclei in the production of the elements in the Big Bang and in stars.

  2. Superheavy sterile neutrinos as dark matter 

    E-Print Network [OSTI]

    Tang, Yongjun

    2000-01-01T23:59:59.000Z

    (10) GUT Higgs condensate in the very early universe, with no phase transition. (This behavior near the Big Bang singularity is analogous to the behavior of an ordinary superfluid near a vortex singularity.) Superheavy "right-handed neutrinos...

  3. BOSS Measures the Universe to One-Percent Accuracy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    part of the mix. By 380,000 years after the big bang, however, the temperature of the expanding mixture had cooled enough for light to escape, suffusing the newly transparent...

  4. amide deuterium isotope: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in this system, which implies Omega(Baryon) < 0.016 for a Hubble constant of 100 kmsecMpc. This new upper limit on Omega(Baryon) relieves the conflict with standard Big Bang...

  5. 8.286 The Early Universe, Spring 2004

    E-Print Network [OSTI]

    Guth, Alan

    The Early Universe provides an introduction to modern cosmology. The first half deals with the development of the big-bang theory from 1915 to 1980, and latter half with recent impact of particle theory.

  6. Landscape predictions from cosmological vacuum selection

    E-Print Network [OSTI]

    Bousso, Raphael

    2008-01-01T23:59:59.000Z

    D 33, 3560 (1986). [18] A. Linde: Quantum creation of an in?Rev. D 74, 103516 (2006), hep- th/0606114. [2] A. Linde, D.Linde and A. Mezhlumian: From the big bang theory to the

  7. Annual modulation of cosmic relic neutrinos

    E-Print Network [OSTI]

    Safdi, Benjamin R.

    The cosmic neutrino background (C?B), produced about one second after the big bang, permeates the Universe today. New technological advancements make neutrino capture on beta-decaying nuclei (NCB) a clear path forward ...

  8. Top Science of 2013

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    birth of big black holes, possibly the most powerful events since the big bang. This robotic array screens 100 million objects and runs real-time analysis-autonomously alerting...

  9. Freshman Seminar on New Cosmology MAE 87 8-10 am in EBUII 479

    E-Print Network [OSTI]

    Wang, Deli

    the standard NASA-and (dark energy) CDM (cold dark matter) HC (hierarchical clustering) cosmological model-gravitational-dynamics HGD emerges. According to HGD cosmology, life begins soon after the big bang in hot water oceans

  10. Energy Blog | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    19, 2013 This image shows the barred spiral galaxy NGC 1398. | Image courtesy of the Dark Energy Survey. Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Learn...

  11. Type Ia supernova rate at a redshift of ~;0.1

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    since the Big Bang: Supernovae and Gamma-Ray Bursts, held 3-rst the EROS search for supernovae is reviewed in Sect. 2.2. The EROS search for supernovae The EROS experiment used a

  12. LIFE ON EARTH -- AN ACCIDENT? Chiral Symmetry and the Anthropic Principle

    E-Print Network [OSTI]

    ,

    2013-01-01T23:59:59.000Z

    I discuss the fine-tuning of the nuclear forces and in the formation of nuclei in the production of the elements in the Big Bang and in stars.

  13. Dark Energy and the New Cosmology

    E-Print Network [OSTI]

    Michael S. Turner

    2001-08-07T23:59:59.000Z

    A successor to the standard hot big-bang cosmology is emerging. It greatly extends the highly successful hot big-bang model. A key element of the New Standard Cosmology is dark energy, the causative agent for accelerated expansion. Dark energy is just possibly the most important problem in all of physics. The only laboratory up to the task of studying dark energy is the Universe itself.

  14. CMB constraints on mass and coupling constant of light pseudoscalar particles

    E-Print Network [OSTI]

    Damian Ejlli; Alexander D. Dolgov

    2014-09-15T23:59:59.000Z

    Transformation of CMB photons into light pseudoscalar particles at post big bang nucleosynthesis epoch is considered. Using the present day value of a large scale magnetic field to estimate it at earlier cosmological epochs, the oscillation probability of photons into light pseudoscalar particles with an account of coherence breaking in cosmological plasma is calculated. Demanding that the photon transformation does not lead to an exceedingly large CMB spectral distortion and temperature anisotropy, the constraints on the coupling constant of axion like particles to photons, $ g_{\\phi\\gamma} B \\lesssim (10^{-15} - 10^{-12}) \\textrm{nG}\\times \\textrm{GeV}^{-1}$, are found for the axion like particle mass in the interval $10^{-25}$ eV $\\lesssim m_{\\phi}\\lesssim 10^{-5}$ eV, where $B$ is the strength of the large scale magnetic field at the present time. Our results update the previously obtained ones since we use the density matrix formalism which is more accurate than the wave function approximation for the description of oscillations with an essential coherence breaking. In the axion like particle mass range $10^{-25}$ eV $\\lesssim m_{\\phi}\\lesssim 10^{-14}$ eV, weaker limits, by at least 2 orders of magnitude $g_{\\phi\\gamma} B \\lesssim 10^{-11}\\textrm{nG}\\times \\textrm{GeV}^{-1}$, are obtained in comparison with the wave function approximation. In the mass range $10^{-14}$ eV $\\lesssim m_{\\phi}\\lesssim 10^{-5}$ eV, on the other hand, limits that are stronger, by more than an order of magnitude are obtained. Our results are derived by using upper limits on spectral distortion parameter $\\mu$ and temperature anisotropy $\\Delta T/T$ found by COBE and expected sensitivities by PIXIE/PRISM.

  15. The 3.5 keV X-ray line signature from annihilating and decaying dark matter in Weinberg model

    E-Print Network [OSTI]

    Seungwon Baek; P. Ko; Wan-Il Park

    2014-05-28T23:59:59.000Z

    Recently two groups independently observed unidentified X-ray line signal at the energy 3.55 keV from the galaxy clusters and Andromeda galaxy. We show that this anomalous signal can be explained in annihilating dark matter model, for example, fermionic dark matter model in hidden sector with global $U(1)_X$ symmetry proposed by Weinberg. There are two scenarios for the production of the annihilating dark matters. In the first scenario the dark matters with mass 3.55 keV decouple from the interaction with Goldstone bosons and go out of thermal equilibrium at high temperature ($>$ 1 TeV) when they are still relativistic, their number density per comoving volume being essentially fixed to be the current value. The correct relic abundance of this warm dark matter is obtained by assuming that about ${\\cal O}(10^3)$ relativistic degrees of freedom were present at the decoupling temperature or alternatively large entropy production occurred at high temperature. In the other scenario, the dark matters were absent at high temperature, and as the universe cools down, the SM particles annihilate or decay to produce the dark matters non-thermally as in `freeze-in' scenario. It turns out that the DM production from Higgs decay is the dominant one. In the model we considered, only the first scenario can explain both X-ray signal and relic abundance. The X-ray signal arises through $p$-wave annihilation of dark matter pair into two photons through the scalar resonance without violating the constraints from big bang nucleosynthesis, cosmic microwave background, and astrophysical objects such as red giants or white dwarfs. We also discuss the possibility that the signal may result from a decaying dark matter in a simple extension of Weinberg model.

  16. Unified description of $^6$Li structure and deuterium-$^4$He dynamics with chiral two- and three-nucleon forces

    E-Print Network [OSTI]

    Guillaume Hupin; Sofia Quaglioni; Petr Navrátil

    2014-12-12T23:59:59.000Z

    Prototype for the study of weakly bound projectiles colliding on stable targets, the scattering of deuterium ($d$) on $^4$He ($\\alpha$) is an important milestone in the search for a fundamental understanding of low-energy reactions. At the same time, it is also important for its role in the Big-bang nucleosynthesis of $^6$Li and applications in the characterization of deuterium impurities in materials. We present the first unified {\\em ab initio} study of the $^6$Li ground state and $d$-$^4$He elastic scattering using two- and three-nucleon forces derived within the framework of chiral effective field theory. The six-nucleon bound-state and scattering observables are calculated by means of the no-core shell model with continuum. %and are compared to available experimental data. We analyze the influence of the dynamic polarization of the deuterium and of the chiral three-nucleon force, and examine the role of the continuum degrees of freedom in shaping the low-lying spectrum of $^6$Li. We find that the adopted Hamiltonian correctly predicts the binding energy of $^6$Li, yielding an asymptotic $D$- to $S$-state ratio of the $^6$Li wave function in $d+\\alpha$ configuration of $-0.027$ in agreement with the value determined from a phase shift analysis of $^6$Li+$^4$He elastic scattering, but overestimates the excitation energy of the first $3^+$ state by $350$ keV. The bulk of the computed differential cross section is in good agreement with data.

  17. Measuring the Density Fluctuation From the Cluster Gas Mass Function

    E-Print Network [OSTI]

    Kazuhiro Shimasaku

    1997-01-27T23:59:59.000Z

    We investigate the gas mass function of clusters of galaxies to measure the density fluctuation spectrum on cluster scales. The baryon abundance confined in rich clusters is computed from the gas mass function and compared with the mean baryon density in the universe which is predicted by the Big Bang Nucleosynthesis. This baryon fraction and the slope of the gas mass function put constraints on $\\sigma_8$, the rms linear fluctuation on scales of $8h^{-1}\\Mpc$, and the slope of the fluctuation spectrum, where $h$ is the Hubble constant in units of 100 $\\kms \\oMpc$. We find $\\sigma_8 = 0.80 \\pm 0.15$ and $n \\sim -1.5$ for $0.5 \\le h \\le 0.8$, where we assume that the density spectrum is approximated by a power law on cluster scales: $\\sigma(r) \\propto r^{-{3+n\\over{2}}}$. Our value of $\\sigma_8$ is independent of the density parameter, $\\Omega_0$, and thus we can estimate $\\Omega_0$ by combining $\\sigma_8$ obtained in this study with those from $\\Omega_0$-dependent analyses to date. We find that $\\sigma_8(\\Omega_0)$ derived from the cluster abundance such as the temperature function gives $\\Omega_0 \\sim 0.5$ while $\\sigma_8(\\Omega_0)$ measured from the peculiar velocity field of galaxies gives $\\Omega_0 \\sim 0.2-1$, depending on the technique used to analyze peculiar velocity data. Constraints are also derived for open, spatially flat, and tilted Cold Dark Matter models and for Cold + Hot Dark Matter models.

  18. Vacuum effects of ultra-low mass particle account for Recent Acceleration of Universe

    E-Print Network [OSTI]

    Leonard Parker; Alpan Raval

    1999-08-04T23:59:59.000Z

    In recent work, we showed that non-perturbative vacuum effects of a very low mass particle could induce, at a redshift of order 1, a transition from a matter-dominated to an accelerating universe. In that work, we used the simplification of a sudden transition out of the matter-dominated stage and were able to fit the Type Ia supernovae (SNe-Ia) data points with a spatially-open universe. In the present work, we find a more accurate, smooth {\\it spatially-flat} analytic solution to the quantum-corrected Einstein equations. This solution gives a good fit to the SNe-Ia data with a particle mass parameter $m_h$ in the range $6.40 \\times 10^{-33}$ eV to $7.25 \\times 10^{-33}$ eV. It follows that the ratio of total matter density (including dark matter) to critical density, $\\O_0$, is in the range 0.58 to 0.15, and the age $t_0$ of the universe is in the range $8.10 h^{-1}$ Gyr to $12.2 h^{-1}$ Gyr, where $h$ is the present value of the Hubble constant, measured as a fraction of the value 100 km/(s Mpc). This spatially-flat model agrees with estimates of the position of the first acoustic peak in the small angular scale fluctuations of the cosmic background radiation, and with light-element abundances of standard big-bang nucleosynthesis. Our model has only a single free parameter, $m_h$, and does not require that we live at a special time in the evolution of the universe.

  19. Incompatibility of a comoving Ly-alpha forest with supernova-Ia luminosity distances

    E-Print Network [OSTI]

    Jens Thomas; Hartmut Schulz

    2001-03-18T23:59:59.000Z

    Recently Perlmutter et al. suggested a positive value of Einstein's cosmological constant Lambda on the basis of luminosity distances from type-Ia supernovae. However, Lambda world models had earlier been proposed by Hoell & Priester and Liebscher et al. on the basis of quasar absorption-line data. Employing more general repulsive fluids ("dark energy") encompassing the Lambda component we quantitatively compare both approaches with each other. Fitting the SN-data by a minimum-component model consisting of dark energy + dust yields a closed universe with a large amount of dust exceeding the baryonic content constrained by big-bang nucleosynthesis. The nature of the dark energy is hardly constrained. Only when enforcing a flat universe there is a clear tendency to a dark-energy Lambda fluid and the `canonical' value Omega_M = 0.3 for dust. Conversely, fitting the quasar-data by a minimum-component model yields a sharply defined, slightly closed model with a low dust density ruling out significant pressureless dark matter. The dark-energy component obtains an equation-of-state P = -0.96 epsilon close to that of a Lambda-fluid. Omega_M = 0.3 or a precisely flat spatial geometry are inconsistent with minimum-component models. It is found that quasar and supernova data sets cannot be reconciled with each other via (repulsive ideal fluid+dust+radiation)-world models. Compatibility could be reached by drastic expansion of the parameter space with at least two exotic fluids added to dust and radiation as world constituents. If considering such solutions as far-fetched one has to conclude that the quasar absorption line and the SN-Ia constraints are incompatible.

  20. Collisional production of sterile neutrinos via secret interactions and cosmological implications

    E-Print Network [OSTI]

    Alessandro Mirizzi; Gianpiero Mangano; Ofelia Pisanti; Ninetta Saviano

    2014-12-16T23:59:59.000Z

    Secret interactions among sterile neutrinos have been recently proposed as an escape-route to reconcile eV sterile neutrino hints from short-baseline anomalies with cosmological observations. In particular models with coupling g_X \\gtrsim 10^{-2} and gauge boson mediators $X$ with $M_X \\lesssim 10$ MeV lead to large matter potential suppressing the sterile neutrino production before the neutrino decoupling. With this choice of parameter ranges, big bang nucleosynthesis is left unchanged and gives no bound on the model. However, we show that at lower temperatures when active-sterile oscillations are no longer matter suppressed, sterile neutrinos are still in a collisional regime, due to their secret self-interactions. The interplay between vacuum oscillations and collisions leads to a scattering-induced decoherent production of sterile neutrinos with a fast rate. This process is responsible for a flavor equilibration among the different neutrino species. We explore the effect of this large sterile neutrino population on cosmological observables. We find that a signature of strong secret interactions would be a reduction of the effective number of neutrinos $N_{\\rm eff}$ at matter radiation equality down to 2.7. Moreover, for $M_X \\gtrsim g_X$ MeV sterile neutrinos would be free-streaming before becoming non-relativistic and they would affect the large-scale structure power spectrum. As a consequence, for this range of parameters we find a tension of a eV mass sterile state with cosmological neutrino mass bounds.

  1. Surface brightness in plasma-redshift cosmology

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2006-05-31T23:59:59.000Z

    In 2001 Lori M. Lubin and Allan Sandage, using big-bang cosmology for interpreting the data, found the surface brightness of galaxies to be inversely proportional to about the third power of (1+z), while the contemporary big-bang cosmology predicts that the surface brightness is inversely proportional to the fourth power of (1+z). In contrast, these surface brightness observations are in agreement with the predictions of the plasma-redshift cosmology. Lubin and Sandage (2001) and Barden et al. (2005), who surmised the big-bang expansion, interpreted the observations to indicate that the diameters of galaxies are inversely proportional to (1+z). In contrast, when assuming plasma-redshift cosmology, the diameters of galaxies are observed to be constant independent of redshift and any expansion. Lubin and Sandage (2001) and Barden et al. (2005), when using big-bang cosmology, observed the average absolute magnitude of galaxies to decrease with redshift; while in plasma redshift cosmology it is a constant. Lubin and Sandage and Barden et al. suggested that a coherent evolution could explain the discrepancy between the observed relations and those predicted in the big-bang cosmology. We have failed to find support for this explanation. We consider the observed relations between the redshift and the surface-brightness, the galaxy diameter, and the absolute magnitude to be robust confirmations of plasma-redshift cosmology.

  2. Turbulence and turbulent mixing in natural fluids

    E-Print Network [OSTI]

    Gibson, Carl H

    2010-01-01T23:59:59.000Z

    Turbulence and turbulent mixing in natural fluids begins with big bang turbulence powered by spinning combustible combinations of Planck particles and Planck antiparticles. Particle prograde accretion on a spinning pair releases 42% of the particle rest mass energy to produce more fuel for turbulent combustion. Negative viscosity and negative turbulence stresses work against gravity, creating mass-energy and space-time from the vacuum. Turbulence mixes cooling temperatures until a quark-gluon strong-force SF freeze-out. Gluon-viscosity anti-gravity ({\\Lambda}SF) exponentially inflates the fireball to preserve big bang turbulence information at scales larger than ct as the first fossil turbulence. Cosmic microwave background CMB temperature anisotropies show big bang turbulence fossils along with fossils of weak plasma turbulence triggered (10^12 s) as plasma viscous forces permit gravitational fragmentation on supercluster to galaxy mass scales (10^13 s). Turbulent morphologies and viscous-turbulent lengths a...

  3. Propagation of gravitational waves in a universe with slowly-changing equation of state

    E-Print Network [OSTI]

    Edmund Schluessel

    2014-06-17T23:59:59.000Z

    An exact solution for the expansion of a flat universe with dark energy evolving according to a simple model is explored. The equation for weak primordial gravitational waves propagating in this universe is solved and explored; gravitational waves in a flat cosmology possessing both a "big bang" singularity and a "big rip" singularity can be described with confluent Heun functions. We develop approximation methods for confluent Heun equations in regimes of interest to gravitational wave astronomers and predict the diminution in gravitational wave amplitude in a universe with both a Big Bang and a Big Rip.

  4. Higgs boson cosmology

    E-Print Network [OSTI]

    Ian G. Moss

    2015-07-21T23:59:59.000Z

    The discovery of the Standard Model Higgs boson opens up a range of speculative cosmological scenarios, from the formation of structure in the early universe immediately after the big bang, to relics from the electroweak phase transition one nanosecond after the big bang, on to the end of the present-day universe through vacuum decay. Higgs physics is wide-ranging, and gives an impetus to go beyond the Standard Models of particle physics and cosmology to explore the physics of ultra-high energies and quantum gravity.

  5. Classical and quantum Big Brake cosmology for scalar field and tachyonic models

    SciTech Connect (OSTI)

    Kamenshchik, A. Yu. [Dipartimento di Fisica e Astronomia and INFN, Via Irnerio 46, 40126 Bologna (Italy) and L.D. Landau Institute for Theoretical Physics of the Russian Academy of Sciences, Kosygin str. 2, 119334 Moscow (Russian Federation); Manti, S. [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy)

    2013-02-21T23:59:59.000Z

    We study a relation between the cosmological singularities in classical and quantum theory, comparing the classical and quantum dynamics in some models possessing the Big Brake singularity - the model based on a scalar field and two models based on a tachyon-pseudo-tachyon field . It is shown that the effect of quantum avoidance is absent for the soft singularities of the Big Brake type while it is present for the Big Bang and Big Crunch singularities. Thus, there is some kind of a classical - quantum correspondence, because soft singularities are traversable in classical cosmology, while the strong Big Bang and Big Crunch singularities are not traversable.

  6. Formation of super-heavy elements in astrophysical nucleosynthesis

    SciTech Connect (OSTI)

    Zagrebaev, V. I.; Karpov, A. V.; Mishustin, I. N.; Greiner, Walter [Flerov Laboratory of Nuclear Reactions, JINR, Dubna, Moscow Region (Russian Federation); Frankfurt Institute for Advanced Studies, J.W. Goethe-Universitaet, Frankfurt (Germany)

    2012-10-20T23:59:59.000Z

    The unexplored area of heavy neutron-rich nuclides is extremely important for the understanding of the r process of astrophysical nucleogenesis. For elements with Z>100 only neutron deficient isotopes (located to the left of the stability line) have been synthesized so far. The 'north-east' area of the nuclear map can be reached neither in fusion reactions nor in fragmentation processes. Low energy multi-nucleon transfer reactions are quite promising for the production and study of neutron-rich heavy nuclei including those located at the superheavy (SH) island of stability [1]. The neutron capture process is considered here as an alternative method for the production of SH nuclei. Requirements for the pulsed reactors of the next generation that could be used for the synthesis of long-living neutron rich SH nuclei are formulated. Formation of SH nuclei in supernova explosions is also discussed and the abundance of SH elements in nature is estimated.

  7. Experimental techniques to investigate the p process of nucleosynthesis

    E-Print Network [OSTI]

    Zilges, Andreas

    ) 127 #12;Activation measurement HPG Decay of 147,149Nd HPGe detector activated -: 147Nd147Pm -: 149Nd149Pm Shielding activated target : 149Nd149Pm Nd ­ X-rays Energy [keV] Reaction Yield: d

  8. Neutrinos and Nucleosynthesis in Gamma-Ray Burst Accretion Disks

    E-Print Network [OSTI]

    R. Surman; G. C. McLaughlin

    2003-11-24T23:59:59.000Z

    We calculate the nuclear composition of matter in accretion disks surrounding stellar mass black holes as are thought to accompany gamma-ray bursts (GRBs). We follow a mass element in the accretion disk starting at the point of nuclear dissociation and calculate the evolution of the electron fraction due to electron, positron, electron neutrino and electron antineutrino captures. We find that the neutronization of the disk material by electron capture can be reversed by neutrino interactions in the inner regions of disks with accretion rates of 1 M_solar/s and higher. For these cases the inner disk regions are optically thick to neutrinos, and so to estimate the emitted neutrino fluxes we find the surface of last scattering for the neutrinos (the equivalent of the proto-neutron star neutrinosphere) for each optically thick disk model. We also estimate the influence of neutrino interactions on the neutron-to-proton ratio in outflows from GRB accretion disks, and find it can be significant even when the disk is optically thin to neutrinos.

  9. Constraints on Supersymmetric Models from Catalytic Primordial Nucleosynthesis of Beryllium

    E-Print Network [OSTI]

    Maxim Pospelov; Josef Pradler; Frank Daniel Steffen

    2008-10-27T23:59:59.000Z

    The catalysis of nuclear reactions by negatively charged relics leads to increased outputs of primordial ^6Li and ^9Be. In combination with observational constraints on the primordial fractions of ^6Li and ^9Be, this imposes strong restrictions on the primordial abundance and the lifetime of charged relics. We analyze the constraints from the catalysis of ^9Be on supersymmetric models in which the gravitino is the lightest supersymmetric particle and a charged slepton--such as the lighter stau--the next-to-lightest supersymmetric particle (NLSP). Barring the special cases in which the primordial fraction of the slepton NLSP is significantly depleted, we find that the ^9Be data require a slepton NLSP lifetime of less than 6x10^3 seconds. We also address the issue of the catalytic destruction of ^6Li and ^9Be by late forming bound states of protons with negatively charged relics finding that it does not lead to any significant modification of the limit on the slepton lifetime.

  10. Nucleosynthesis in type Ia supernovae driven by asymmetric thermonuclear ignition

    SciTech Connect (OSTI)

    Maeda, Keiichi [Institute for the Physics and Mathematics of the Universe (IPMU), Todai Institutes for Advanced Study (TODIAS), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan)

    2012-11-12T23:59:59.000Z

    Type Ia Supernovae (SNe Ia) are believed to be thermonuclear explosions of a white dwarf. They can be used as mature cosmological standardized candles, leading to the discovery of the accelerating expansion of the Universe. However, the explosion mechanism has not yet been fully clarified. In this paper, we first present nucleosynthetic features of a leading explosion scenario, namely a delayed-detonation scenario. Based on this, we propose a new and strong observational constraint on the explosion mechanism through emission lines from neutron-rich Fe-peaks. Especially, we show that an asymmetry in the explosion is likely a generic feature. We further argue that the diversity arising from various viewing angles can be an origin of observational diversities of SNe Ia seen in their spectral features (suspected possible biases in cosmology) and colors (related to the extinction estimate in cosmology). Using these new insights could open up a possibility of using SNe Ia as more precise distance indicators than currently employed.

  11. Thermal Distributions, Saha Equation, Weak Interactions This chapter deals with some background issues important to modeling the BBN as well as

    E-Print Network [OSTI]

    Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

    Chapter 3 Thermal Distributions, Saha Equation, Weak Interactions This chapter deals with some · the Saha equation · low-energy weak interactions 3.1 Thermal distributions The thermal distributions to be considered: the Saha equation discussion will il- lustrate this.) The parameter µ, the chemical potential

  12. Columbia University http://www.columbia.edu/~mem4/

    E-Print Network [OSTI]

    Mauel, Michael E.

    Mike Mauel Columbia University http://www.columbia.edu/~mem4/ National Undergraduate Fusion plant · Columbia University's plasma physics experiments 6Friday, June 5, 2009 #12;Forces of Nature, 2009 100-300 s after the "Big-Bang": The Age of Fusion · At 100 sec, the universe cools to 1

  13. The Royal Observatory Edinburgh comprises the UK Astronomy Technology Centre of the Science and Technology Facilities Council, the Institute for Astronomy of the University of Edinburgh and the ROE Visitor Centre.

    E-Print Network [OSTI]

    Tittley, Eric

    for designing and building the spectrometer pre-optics sub-system, which includes a set of four image slicers a hexagonal primary mirror with a collecting area of 25 square metres, passively cooled to 40K and placed, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable

  14. From Pinholes to Black Holes

    SciTech Connect (OSTI)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-06T23:59:59.000Z

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  15. Waves in Nature, Lasers to Tsumanis and Beyond

    ScienceCinema (OSTI)

    LLNL - University of California Television

    2009-09-01T23:59:59.000Z

    Waves are everywhere. Microwaves, laser beams, music, tsunamis. Electromagnetic waves emanating from the Big Bang fill the universe. Learn about the similarities and difference in all of these wavy phenomena with Ed Moses and Rick Sawicki, Lawrence Livermore National Laboratory scientists Series: Science on Saturday [10/2006] [Science] [Show ID: 11541

  16. Search for Dark Matter WIMPs using Upward-Going Muons in

    E-Print Network [OSTI]

    Tokyo, University of

    Search for Dark Matter WIMPs using Upward-Going Muons in Super{Kamiokande S. Desai, for the Super{Kamiokande searches for Weakly Interacting Massive Particles (WIMPs) with the Super-Kamiokande detector using neutrino, for the Super{Kamiokande Collaboration the Universe as a cosmological relic from the Big Bang. The most likely

  17. 7 de janeiro de 2009 EXPERIMENTO A BORDO DE BALO ESTRATOSFRICO DA NASA, QUE

    E-Print Network [OSTI]

    Domingues, Margarete Oliveira

    medidas do céu em micro-ondas à procura da energia emitida pelas primeiras estrelas que se formaram qual o nosso Sistema Solar pertence. O Universo é permeado por um sinal residual do Big Bang, observado causados pelo decaimento de partículas primordiais ou pela injeção de energia no Universo produzida pela

  18. Name ___KEY_______________ Due Date: __________________

    E-Print Network [OSTI]

    Kirby, Carl S.

    solar system formed. Following the Big Bang, some first generation stars became supernovae, spreading an atmosphere with about 20% oxygen, compared to no free oxygen early in the Earth's history? Write down. Photosynthesis by algae eventually produced free oxygen in the atmosphere, which allowed for development of air

  19. Copper vs. Copper at the Relativistic Heavy Ion Collider (2005)

    ScienceCinema (OSTI)

    Brookhaven Lab - Fulvia Pilat

    2010-01-08T23:59:59.000Z

    To investigate a new form of matter not seen since the Big Bang, scientists are using a new experimental probe: collisions between two beams of copper ions. The use of intermediate size nuclei is expected to result in intermediate energy density - not as

  20. TROPICAL STORMS SUPER SIMULATIONS

    E-Print Network [OSTI]

    Fukai, Tomoki

    physical sciences 15 A new flavor of superconductor Computer simulations show how fundamental particles behave like electrons in a superconductor 16 Higgs versus the Big Bang The Higgs boson could help explain The magnetic interactions in beryllium-11 could explain its unusual shape 19 A solitary superconductor emerges

  1. A search for particle dark matter using cryogenic germanium and silicon detectors in the one- and two- tower runs of CDMS-II at Soudan

    SciTech Connect (OSTI)

    Ogburn, Reuben Walter, IV; /Stanford U., Phys. Dept.

    2008-04-01T23:59:59.000Z

    Images of the Bullet Cluster of galaxies in visible light, X-rays, and through gravitational lensing confirm that most of the matter in the universe is not composed of any known form of matter. The combined evidence from the dynamics of galaxies and clusters of galaxies, the cosmic microwave background, big bang nucleosynthesis, and other observations indicates that 80% of the universe's matter is dark, nearly collisionless, and cold. The identify of the dar, matter remains unknown, but weakly interacting massive particles (WIMPs) are a very good candidate. They are a natural part of many supersymmetric extensions to the standard model, and could be produced as a nonrelativistic, thermal relic in the early universe with about the right density to account for the missing mass. The dark matter of a galaxy should exist as a spherical or ellipsoidal cloud, called a 'halo' because it extends well past the edge of the visible galaxy. The Cryogenic Dark Matter Search (CDMS) seeks to directly detect interactions between WIMPs in the Milky Way's galactic dark matter halo using crystals of germanium and silicon. Our Z-sensitive ionization and phonon ('ZIP') detectors simultaneously measure both phonons and ionization produced by particle interactions. In order to find very rare, low-energy WIMP interactions, they must identify and reject background events caused by environmental radioactivity, radioactive contaminants on the detector,s and cosmic rays. In particular, sophisticated analysis of the timing of phonon signals is needed to eliminate signals caused by beta decays at the detector surfaces. This thesis presents the firs two dark matter data sets from the deep underground experimental site at the Soudan Underground Laboratory in Minnesota. These are known as 'Run 118', with six detectors (1 kg Ge, 65.2 live days before cuts) and 'Run 119', with twelve detectors (1.5 kg Ge, 74.5 live days before cuts). They have analyzed all data from the two runs together in a single, combined analysis, with sensitivity to lower-energy interactions, careful control of data quality and stability, and further development of techniques for reconstructing event location and rejecting near-surface interactions from beta decays. They also present a revision to the previously published Run 119 analysis, a demonstration of the feasibility of a low-threshold (1 or 2 keV) analysis of Soudan data, and a review of the literature on charge generation and quenching relevant to the ionization signal.

  2. On the Universal Generation of Mobility Models Alberto Medina

    E-Print Network [OSTI]

    On the Universal Generation of Mobility Models Alberto Medina Raytheon BBN Technologies amedina@bbn.com Gonca Gursun Computer Science Dept. Boston University goncag@cs.bu.edu Prithwish Basu Raytheon BBN

  3. Algorithms for Channel Assignment in Mobile Wireless Networks using Temporal Coloring

    E-Print Network [OSTI]

    Ramanathan, Ram

    of New York Graduate Center New York, NY, 10016, USA amotz@sci.brooklyn.cuny.edu Prithwish Basu Raytheon BBN Technologies Cambridge, MA, 02138, USA pbasu@bbn.com Ram Ramanathan Raytheon BBN Technologies

  4. Grit Denker, Ph.D. SRI International

    E-Print Network [OSTI]

    Denker, Grit

    and countermeasures of cognitive radios. PI of subcontract to Raytheon BBN Technologies architecture for MANET clusters in space applications designed by Raytheon BBN. PI

  5. bu.edu/eng4 ACCESS DENIED

    E-Print Network [OSTI]

    , Deutsche Telekom and Raytheon BBN Technologies; and one academic partner, Warwick University. The ECE

  6. The Origin of the Elements

    ScienceCinema (OSTI)

    Murphy, Edward

    2014-08-06T23:59:59.000Z

    The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present day, and beyond. You will learn how the elements were forged in the nuclear furnaces inside stars, and how, when they die, these massive stars spread the elements into space. You will learn about the origin of the building blocks of matter in the Big Bang, and we will speculate on the future of the atoms around us today.

  7. Stable bounce and inflation in non-local higher derivative cosmology

    SciTech Connect (OSTI)

    Biswas, Tirthabir [Department of Physics, Loyola University, 6363 St. Charles Avenue, Campus Box 92, New Orleans (United States); Koshelev, Alexey S. [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, B-1050, Brussels (Belgium); Mazumdar, Anupam [Consortium for Fundamental Physics, Physics Department, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Vernov, Sergey Yu., E-mail: tbiswas@loyno.edu, E-mail: alexey.koshelev@vub.ac.be, E-mail: a.mazumdar@lancaster.ac.uk, E-mail: svernov@theory.sinp.msu.ru [Instituto de Ciencias del Espacio, Institut d'Estudis Espacials de Catalunya, Campus UAB, Facultat de Ciències, Torre C5-Parell-2a planta, E-08193, Bellaterra (Barcelona) (Spain)

    2012-08-01T23:59:59.000Z

    One of the greatest problems of primordial inflation is that the inflationary space-time is past-incomplete. This is mainly because Einstein's GR suffers from a space-like Big Bang singularity. It has recently been shown that ghost-free, non-local higher-derivative ultra-violet modifications of Einstein's gravity may be able to resolve the cosmological Big Bang singularity via a non-singular bounce. Within the framework of such non-local cosmological models, we are going to study both sub- and super-Hubble perturbations around an inflationary trajectory which is preceded by the Big Bounce in the past, and demonstrate that the inflationary trajectory has an ultra-violet completion and that perturbations do not suffer from any pathologies.

  8. Higher Dimensional Szekeres' Space-time in Brans-Dicke Scalar Tensor Theory

    E-Print Network [OSTI]

    Asit Banerjee; Ujjal Debnath; Subenoy Chakraborty

    2004-04-21T23:59:59.000Z

    The generalized Szekeres family of solution for quasi-spherical space-time of higher dimensions are obtained in the scalar tensor theory of gravitation. Brans-Dicke field equations expressed in Dicke's revised units are exhaustively solved for all the subfamilies of the said family. A particular group of solutions may also be interpreted as due to the presence of the so-called C-field of Hoyle and Narlikar and for a chosen sign of the coupling parameter. The models show either expansion from a big bang type of singularity or a collapse with the turning point at a lower bound. There is one particular case which starts from the big bang, reaches a maximum and collapses with the in course of time to a crunch.

  9. Matter Under Extreme Conditions: The Early Years

    E-Print Network [OSTI]

    Keeler, R Norris

    2010-01-01T23:59:59.000Z

    Extreme conditions in natural flows are examined, starting with a turbulent big bang. A hydro-gravitational-dynamics cosmology model is adopted. Planck-Kerr turbulence instability causes Planck-particle turbulent combustion. Inertial-vortex forces induce a non-turbulent kinetic energy cascade to Planck-Kolmogorov scales where vorticity is produced, overcoming 10^113 Pa Planck-Fortov pressures. The spinning, expanding fireball has a slight deficit of Planck antiparticles. Space and mass-energy powered by gluon viscous stresses expand exponentially at speeds >10^25 c. Turbulent temperature and spin fluctuations fossilize at scales larger than ct, where c is light speed and t is time. Because â??dark-energyâ? antigravity forces vanish when inflation ceases, and because turbulence produces entropy, the universe is closed and will collapse and rebound. Density and spin fossils of big bang turbulent mixing trigger structure formation in the plasma epoch. Fragmenting protosuperclustervoids and protoclustervoi...

  10. Gravity-anti-Gravity Symmetric Mini-Superspace: Quantum Entanglement and Cosmological Scale Factor Grid

    E-Print Network [OSTI]

    Aharon Davidson; Tomer Ygael

    2014-10-22T23:59:59.000Z

    A gravity-anti-gravity (GaG) odd linear dilaton action offers an eternal inflation evolution governed by the unified (cosmological constant plus radiation) equation of state $\\rho-3P=4\\Lambda$. At the mini superspace level, a 'two-particle' variant of the no-boundary proposal, notably 'one-particle' energy dependent, is encountered. While a GaG-odd wave function can only host a weak Big Bang boundary condition, albeit for any $k$, a strong Big Bang boundary condition requires a GaG-even entangled wave function, and singles out $k=0$ flat space. The locally most probable values for the cosmological scale factor and the dilaton field form a grid $\\{a^2,a\\phi\\}\\sim\\sqrt{4n_1+1}\\pm\\sqrt{4n_2+1}$.

  11. Instantaneous Power Radiated from Magnetic Dipole Moments

    E-Print Network [OSTI]

    Peter D. Morley; Douglas J. Buettner

    2014-07-04T23:59:59.000Z

    We compute the power radiated per unit solid angle of a moving magnetic dipole moment, and its instantaneous radiated power, both non-relativistically and relativistically. This is then applied to various interesting situations: solar neutrons, electron synchrotrons and cosmological Dirac neutrinos. Concerning the latter, we show that hypothesized early-universe Big Bang conditions allow for neutrino radiation cooling and provide an energy loss-mechanism for subsequent neutrino condensation.

  12. Columbia University http://www.columbia.edu/~mem4/

    E-Print Network [OSTI]

    Mauel, Michael E.

    Mike Mauel Columbia University http://www.columbia.edu/~mem4/ and Jefferson Science Fellow EEB slow! #12;100-300 s after the "Big-Bang": The Age of Fusion · At 100 sec, the universe cools to 1,000,000,000° · Protons and neutrons fuse to Deuterium (heavy hydrogen).The whole universe is a "burning plasma"! · D + D

  13. Gravitational Entropy and the Second Law of Thermodynamics

    E-Print Network [OSTI]

    J. W. Moffat

    2014-07-03T23:59:59.000Z

    The spontaneous violation of Lorentz and diffeomorphism invariance in a phase near the big bang lowers the entropy, allowing for an arrow of time and the second law of thermodynamics. The spontaneous symmetry breaking leads to $O(3,1)\\rightarrow O(3)\\times R$, where $O(3)$ is the rotational symmetry of the Friedmann-Lema\\^{i}tre-Robertson-Walker spacetime. The Weyl curvature tensor $C_{\\mu\

  14. Cosmology, Thermodynamics and Matter Creation

    E-Print Network [OSTI]

    J. A. S. Lima; M. O. Calvao; I. Waga

    2007-08-24T23:59:59.000Z

    Several approaches to the matter creation problem in the context of cosmological models are summarily reviewed. A covariant formulation of the general relativistic imperfect simple fluid endowed with a process of matter creation is presented. By considering the standard big bang model, it is shown how the recent results of Prigogine et alii \\cite{1} can be recovered and, at the same time their limits of validity are explicited.

  15. A dark energy multiverse

    E-Print Network [OSTI]

    Salvador Robles-Perez; Prado Martin-Moruno; Alberto Rozas-Fernandez; Pedro F. Gonzalez-Diaz

    2007-01-23T23:59:59.000Z

    We present cosmic solutions corresponding to universes filled with dark and phantom energy, all having a negative cosmological constant. All such solutions contain infinite singularities, successively and equally distributed along time, which can be either big bang/crunchs or big rips singularities. Classicaly these solutions can be regarded as associated with multiverse scenarios, being those corresponding to phantom energy that may describe the current accelerating universe.

  16. Quark Nuggets as Baryonic Dark Matter

    E-Print Network [OSTI]

    Jan-e Alam; Sibaji Raha; Bikash Sinha

    1997-04-23T23:59:59.000Z

    The cosmic first order phase transition from quarks to hadrons, occurring a few microseconds after the Big Bang, would lead to the formation of quark nuggets which would be stable on a cosmological time scale, if the associated baryon number is larger than a critical value. We examine the possibility that these surviving quark nuggets may not only be viable candidates for cold dark matter but even close the universe.

  17. Phantom Friedmann Cosmologies and Higher-Order Characteristics of Expansion

    E-Print Network [OSTI]

    Mariusz P. Dabrowski; Tomasz Stachowiak

    2005-11-25T23:59:59.000Z

    We discuss a more general class of phantom ($p -1$) matter. We show that many types of evolution which include both Big-Bang and Big-Rip singularities are admitted and give explicit examples. Among some interesting models, there exist non-singular oscillating (or "bounce") cosmologies, which appear due to a competition between positive and negative pressure of variety of matter content. From the point of view of the current observations the most interesting cosmologies are the ones which start with a Big-Bang and terminate at a Big-Rip. A related consequence of having a possibility of two types of singularities is that there exists an unstable static universe approached by the two asymptotic models - one of them reaches Big-Bang, and another reaches Big-Rip. We also give explicit relations between density parameters $\\Omega$ and the dynamical characteristics for these generalized phantom models, including higher-order observational characteristics such as jerk and "kerk". Finally, we discuss the observational quantities such as luminosity distance, angular diameter, and source counts, both in series expansion and explicitly, for phantom models. Our series expansion formulas for the luminosity distance and the apparent magnitude go as far as to the fourth-order in redshift $z$ term, which includes explicitly not only the jerk, but also the "kerk" (or "snap") which may serve as an indicator of the curvature of the universe.

  18. On the Weyl curvature hypothesis

    SciTech Connect (OSTI)

    Stoica, Ovidiu Cristinel, E-mail: holotronix@gmail.com

    2013-11-15T23:59:59.000Z

    The Weyl curvature hypothesis of Penrose attempts to explain the high homogeneity and isotropy, and the very low entropy of the early universe, by conjecturing the vanishing of the Weyl tensor at the Big-Bang singularity. In previous papers it has been proposed an equivalent form of Einstein’s equation, which extends it and remains valid at an important class of singularities (including in particular the Schwarzschild, FLRW, and isotropic singularities). Here it is shown that if the Big-Bang singularity is from this class, it also satisfies the Weyl curvature hypothesis. As an application, we study a very general example of cosmological models, which generalizes the FLRW model by dropping the isotropy and homogeneity constraints. This model also generalizes isotropic singularities, and a class of singularities occurring in Bianchi cosmologies. We show that the Big-Bang singularity of this model is of the type under consideration, and satisfies therefore the Weyl curvature hypothesis. -- Highlights: •The singularities we introduce are described by finite geometric/physical objects. •Our singularities have smooth Riemann and Weyl curvatures. •We show they satisfy Penrose’s Weyl curvature hypothesis (Weyl=0 at singularities). •Examples: FLRW, isotropic singularities, an extension of Schwarzschild’s metric. •Example: a large class of singularities which may be anisotropic and inhomogeneous.

  19. Birth of the Universe from the Multiverse

    E-Print Network [OSTI]

    Laura Mersini-Houghton

    2008-09-22T23:59:59.000Z

    It is fair to say that the deepest mystery in our understanding of nature is the birth of our universe. Much of the dilemma over the last decades comes from the extraordinarily small probability that the universe started with the high energy Big Bang as compared to the chance of nucleating any other event. How can Big Bang cosmology be $10^{10^{123}}$ times less likely than nucleating the present cold universe, while accumulating such exquisite agreement with astrophysical data? Why don't we see the other nucleations that, if left to chance, seem to overwhelmingly outnumber us? Here I discuss the point of view that the selection of the initial conditions can be meaningfully addressed only within the framework of the multiverse and that the reason why Big Bang inflation was preferred over other events lies in the quantum dynamics of the landscape of the initial patches. The out-of-equilibrium dynamics selected the 'survivor' universes be born at high energies and the 'terminal' universes at low energies. I briefly review the testable predictions of this theory, in particular the giant void observed in 2007. The second part focuses on the extended framework, in particular a set of postulates needed for defining the multiverse.

  20. Hubble constant from lensing in plasma-redshift cosmology, and intrinsic redshift of quasars

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2004-12-02T23:59:59.000Z

    In a series of articles, we have shown that the newly discovered plasma-redshift cosmology gives a simpler, more accurate and consistent explanation of many cosmological phenomena than the big-bang cosmology. The SNe Ia observations are in better agreement with the magnitude-redshift relation predicted by the plasma redshift than that predicted by the multi-parameter big-bang cosmology. No deceleration or expansion parameters are needed. The plasma-redshift cosmology is flat and quasi-static on a large scale. The Hubble constant is no longer an expansion parameter, but is instead a measure of the average electron density along the line of sight towards an object. Perusal of the SNe Ia data and quasar data has shown that there is no time dilation. The conventional estimates of the Hubble constant from gravitational lensing observations use the big-bang cosmology for interpreting the observations. This has lead to a large spread and discordant estimates of the Hubble constant. The purpose of the present article is to show that the gravitational lensing observations are in agreement with the plasma-redshift cosmology, and to show how to evaluate the lensing observations based on the new plasma-redshift cosmology. The lensing observations also indicate that the quasars have large intrinsic redshifts.

  1. Study of {sup 24}Mg resonances relevant for carbon burning nucleosynthesis

    SciTech Connect (OSTI)

    Toki?, V.; Soi?, N.; Blagus, S.; Fazini?, S.; Jelavi?-Malenica, D.; Miljani?, D.; Prepolec, L.; Skukan, N.; Szilner, S.; Uroi?, M. [Ru?er Boškovi? Institute, Bijeni?ka cesta 54, 10000 Zagreb (Croatia); Milin, M. [Faculty of Science, University of Zagreb, Bijeni?ka cesta 32, 10000 Zagreb (Croatia); Di Pietro, A.; Figuera, P.; Fisichella, M.; Lattuada, M.; Scuderi, V.; Strano, E.; Torresi, D. [INFN-Laboratori Nazionali del Sud, via S.Sofia 62, 95125 Catania (Italy); Freer, M.; Ziman, V. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); and others

    2014-05-09T23:59:59.000Z

    We have studied decays of resonances in {sup 24}Mg at excitation energies above the {sup 12}C+{sup 12}C decay threshold, using {sup 12}C({sup 16}O,?){sup 24}Mg* reaction. This experiment has been performed at INFNLNS, using Tandem accelerator beam of 16O at E = 94 MeV. Some preliminary results are presented.

  2. NUCLEOSYNTHESIS IN INTERMEDIATE MASS STARS JOHN C. LATTANZIO AND CHERYL A. FROST

    E-Print Network [OSTI]

    Lattanzio, John

    are primarily taken from the data base of Thielemann et al (1987). There are some notable exceptions. (All masses given are in units of M fi .) 2.1. CORE HYDROGEN BURNING AND FIRST DREDGE­UP Following core in 13 C at the cost of 12 C. The same region shows a decrease in the 15 N due to 15 N(p,ff) 12 C

  3. Nucleosynthesis of Nickel-56 from Gamma-Ray Burst Accretion Disks

    E-Print Network [OSTI]

    R. Surman; G. C. McLaughlin; N. Sabbatino

    2011-12-12T23:59:59.000Z

    We examine the prospects for producing Nickel-56 from black hole accretion disks, by examining a range of steady state disk models. We focus on relatively slowly accreting disks in the range of 0.05 - 1 solar masses per second, as are thought to be appropriate for the central engines of long-duration gamma-ray bursts. We find that significant amounts of Nickel-56 are produced over a wide range of parameter space. We discuss the influence of entropy, outflow timescale and initial disk position on mass fraction of Nickel-56 which is produced. We keep careful track of the weak interactions to ensure reliable calculations of the electron fraction, and discuss the role of the neutrinos.

  4. Possible signature of hypernova nucleosynthesis in a beryllium rich halo dwarf

    E-Print Network [OSTI]

    R. Smiljanic; L. Pasquini; F. Primas; P. Mazzali; D. Galli; G. Valle

    2008-01-07T23:59:59.000Z

    As part of a large survey of halo and thick disc stars, we found one halo star, HD 106038, exceptionally overabundant in beryllium. In spite of its low metallicity, [Fe/H] = -1.26, the star has log(Be/H) = -10.60, which is similar to the solar meteoritic abundance, log(Be/H) = -10.58. This abundance is more than ten times higher the abundance of stars with similar metallicity and cannot be explained by models of chemical evolution of the Galaxy that include the standard theory of cosmic-ray spallation. No other halo star exhibiting such a beryllium overabundance is known. In addition, overabundances of Li, Si, Ni, Y, and Ba are also observed. We suggest that all these chemical peculiarities, but the Ba abundance, can be simultaneously explained if the star was formed in the vicinity of a hypernova.

  5. Experimental study of beta-delayed proton decay of (23)Al for nucleosynthesis in novae

    E-Print Network [OSTI]

    Saastamoinen, A.; Trache, L.; Banu, A.; Bentley, M. A.; Davinson, T.; Hardy, John C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Tabacaru, G.; Tribble, Robert E.; Woods, P. J.; Aysto, J.

    2011-01-01T23:59:59.000Z

    The beta-delayed gamma and proton decay of (23)Al has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas AandM University. We could detect protons down to an energy of 200 ke...

  6. Neutrino-nucleus reactions and their role for supernova dynamics and nucleosynthesis

    E-Print Network [OSTI]

    Balasi, K G; Martínez-Pinedo, G

    2015-01-01T23:59:59.000Z

    The description of nuclear reactions induced by supernova neutrinos has witnessed significant progress during the recent years. At the energies and momentum transfers relevant for supernova neutrinos neutrino-nucleus cross sections are dominated by allowed transitions, however, often with non-negligible contributions from (first) forbidden transitions. For several nuclei allowed Gamow-Teller strength distributions could be derived from charge-exchange reactions and from inelastic electron scattering data. Importantly the diagonalization shell model has been proven to accurately describe these data and hence became the appropriate tool to calculate the allowed contributions to neutrino-nucleus cross sections for supernova neutrinos. Higher multipole contributions are usually calculated within the framework of the Quasiparticle Random Phase Approximation, which describes the total strength and the position of the giant resonances quite well. This manuscript reviews the recent progress achieved in calculating su...

  7. Experimental study of beta-delayed proton decay of (23)Al for nucleosynthesis in novae 

    E-Print Network [OSTI]

    Saastamoinen, A.; Trache, L.; Banu, A.; Bentley, M. A.; Davinson, T.; Hardy, John C.; Iacob, V. E.; McCleskey, M.; Roeder, B. T.; Simmons, E.; Tabacaru, G.; Tribble, Robert E.; Woods, P. J.; Aysto, J.

    2011-01-01T23:59:59.000Z

    The beta-delayed gamma and proton decay of (23)Al has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas AandM University. We could detect protons down to an energy of 200 ke...

  8. The effect of 12C + 12C rate uncertainties on the evolution and nucleosynthesis of

    E-Print Network [OSTI]

    Herwig, Falk

    Contact: M. E. Bennett, Keele University, meb@astro.keele.ac.uk Published: Bennet et al., Monthly Notices

  9. Clues on the evolution of abundance gradients and on AGB nucleosynthesis

    E-Print Network [OSTI]

    Stasinska, G; Bresolin, F; Tsamis, Yi

    2013-01-01T23:59:59.000Z

    We have obtained deep spectra of 26 planetary nebulae (PNe) and 9 compact HII regions in the nearby spiral galaxy NGC 300, and analyzed them together with those of the giant HII regions previously observed. We have determined the physical properties of all these objects and their He, N, O, Ne, S and Ar abundances in a consistent way. We find that, globally, compact HII regions have abundance ratios similar to those of giant HII regions, while PNe have systematically larger N/O ratios and similar Ne/O and Ar/O ratios. We demonstrate that the nitrogen enhancement in PNe cannot be only due to second dredge-up in the progenitor stars, since their initial masses are around 2--2.5\\,\\msun. An extra mixing process is required, perhaps driven by stellar rotation. Concerning the radial abundance distribution, PNe behave differently from HII regions: in the central part of the galaxy their average O/H abundance ratio is 0.15 dex smaller. Their abundance dispersion at any galactocentric radius is significantly larger tha...

  10. Nucleosynthesis at the proton drip line a challenge for nuclear physics

    E-Print Network [OSTI]

    Rauscher, Thomas

    are thermonuclear flashes on the surface of accreting neutron stars [1--3] (see also the review article [4 in a thermonuclear runaway. Helium is burned via the 3ff­reaction and the ffp­process (a sequence of (ff,p) and (p fuel to power the second burst and can therefore not be explained by the simple #12; thermonuclear

  11. nu-Process Nucleosynthesis in Population III Core-Collapse Supernovae

    E-Print Network [OSTI]

    Takashi Yoshida; Hideyuki Umeda; Ken'ichi Nomoto

    2007-10-01T23:59:59.000Z

    We investigate the effects of neutrino-nucleus interactions (the nu-process) on the production of iron-peak elements in Population III core-collapse supernovae. The nu-process and the following proton and neutron capture reactions produce odd-Z iron-peak elements in complete and incomplete Si burning region. This reaction sequence enhances the abundances of Sc, Mn, and Co in the supernova ejecta. The supernova explosion models of 15 M_sol and 25 M_sol stars with the nu-process well reproduce the averaged Mn/Fe ratio observed in extremely metal-poor halo stars. In order to reproduce the observed Mn/Fe ratio, the total neutrino energy in the supernovae should be 3 - 9 x 10^{53} ergs. Stronger neutrino irradiation and other production sites are necessary to reproduce the observed Sc/Fe and Co/Fe ratios, although these ratios increase by the nu-process.

  12. The Formation of Primordial Luminous Objects

    SciTech Connect (OSTI)

    Ripamonti, Emanuele; /Kapteyn Astron. Inst., Groningen; Abel, Tom; /KIPAC, Menlo Park

    2005-08-04T23:59:59.000Z

    The scientific belief that the universe evolves in time is one of the legacies of the theory of the Big Bang. The concept that the universe has an history started to attract the interest of cosmologists soon after the first formulation of the theory: already Gamow (1948; 1949) investigated how and when galaxies could have been formed in the context of the expanding Universe. However, the specific topic of the formation (and of the fate) of the first objects dates to two decades later, when no objects with metallicities as low as those predicted by primordial nucleosynthesis (Z {approx}< 10{sup -10} {approx} 10{sup -8}Z{sub {circle_dot}}) were found. Such concerns were addressed in two seminal papers by Peebles & Dicke (1968; hereafter PD68) and by Doroshkevich, Zel'Dovich & Novikov (1967; hereafter DZN67), introducing the idea that some objects could have formed before the stars we presently observe. (1) Both PD68 and DZN67 suggest a mass of {approx} 10{sup 5} M{sub {circle_dot}} for the first generation of bound systems, based on the considerations on the cosmological Jeans length (Gamow 1948; Peebles 1965) and the possible shape of the power spectrum. (2) They point out the role of thermal instabilities in the formation of the proto-galactic bound object, and of the cooling of the gas inside it; in particular, PD68 introduces H{sub 2} cooling and chemistry in the calculations about the contraction of the gas. (3) Even if they do not specifically address the occurrence of fragmentation, these papers make two very different assumptions: PD68 assumes that the gas will fragment into ''normal'' stars to form globular clusters, while DZN67 assumes that fragmentation does not occur, and that a single ''super-star'' forms. (4) Finally, some feedback effects as considered (e.g. Peebles & Dicke considered the effects of supernovae). Today most of the research focuses on the issues when fragmentation may occur, what objects are formed and how they influence subsequent structure formation. In these notes we will leave the discussion of feedback to lecture notes by Ferrara & Salvaterra and by Madau & Haardt in this same book and focus only on the aspects of the formation of the first objects. The advent of cosmological numerical hydrodynamics in particular allow a fresh new look at these questions. Hence, these notes will touch on aspects of theoretical cosmology to chemistry, computer science, hydrodynamics and atomic physics. For further reading and more references on the subject we refer the reader to other relevant reviews such as Barkana & Loeb 2001, and more recently Ciardi & Ferrara 2004, Glover 2004 and Bromm & Larson 2004. In these notes, we try to give a brief introduction to only the most relevant aspects. We will start with a brief overview of the relevant cosmological concepts in section 2, followed by a discussion of the properties of primordial material (with particular emphasis to its cooling and its chemistry) in section 3. We will then review the technique and the results of numerical simulations in sections 4 and 5: the former will deal with detailed 3D simulations of the formation of gaseous clouds which are likely to transform into luminous objects, while the latter will examine results (mostly from 1D codes) about the modalities of such transformation. Finally, in section 6 we will critically discuss the results of the previous sections, examining their consequences and comparing them to our present knowledge of the universe.

  13. Review of Hypothesis Alignment Algorithms for MT System Combination via Confusion Network Decoding

    E-Print Network [OSTI]

    ,ney}@cs.rwth-aachen.de f Raytheon BBN Technologies, 10 Moulton Street, Cambridge, MA 02138 {smatsouk. The work reported in this paper was carried out while the authors were at Raytheon BBN Technologies

  14. Montage: An X-Based Multimedia Electronic Mail System

    E-Print Network [OSTI]

    Edwards, Keith

    available for Unix systems, the best-known of these being BBN Slate, the Andrew Message System, and NeXTmail. Each of these suffers from its own set of problems. For example, the BBN Slate system provides users with a number of tools for compos- ing complex mail messages. BBN Slate messages can even Graphics

  15. EMNLP-CoNLL 2012 Joint Conference on Empirical Methods in Natural

    E-Print Network [OSTI]

    Shared Task iii #12;#12;Organizers: Sameer Pradhan, Raytheon BBN Technologies Alessandro Moschitti of Pennsylvania Martha Palmer, University of Colorado Lance Ramshaw, Raytheon BBN Technologies Ralph Weischedel, Raytheon BBN Technologies Program Committee: Jie Cai, HITS gGmbH Kadri Hacio

  16. Multiphase transport model for relativistic heavy ion collisions 

    E-Print Network [OSTI]

    Lin, ZW; Ko, Che Ming; Li, Ba; Zhang, B.; Pal, S.

    2005-01-01T23:59:59.000Z

    that for producing a plasma of deconfined quarks and gluons, which is believed to have existed during the first microsecond after the Big Bang. Experiments at the BNL Relativistic Heavy Ion Collider (RHIC) with center-of-mass energy up to ?sNN = 200 GeV in Au... will have an even higher temperature and a nearly vanishing net baryon chemical potential. Many observables have beenmeasured at RHIC, such as the rapidity distributions of various particles and their transverse momentum spectra up to very high...

  17. Gravitational Collapse and Radiation of Grand Unified Theory

    E-Print Network [OSTI]

    Yi-Fang Chang

    2007-10-02T23:59:59.000Z

    The infinite gravitational collapse of any supermassive stars should pass through an energy scale of the grand unified theory (GUT). After nucleon-decays, the supermassive star will convert nearly all its mass into energy, and produce the radiation of GUT. It may probably explain some ultrahigh energy puzzles in astrophysics, for example, quasars and gamma-ray bursts (GRB), etc. This is similar with a process of the Big Bang Universe with a time-reversal evolution in much smaller space scale and mass scale. In this process the star seems be a true white hole.

  18. No excess of bright galaxies around the redshift 7.1 quasar ULAS J1120+0641

    E-Print Network [OSTI]

    Simpson, Chris; Mortlock, Daniel; Warren, Stephen; Cantalupo, Sebastiano; Hewett, Paul; McLure, Ross; McMahon, Richard; Venemans, Bram

    2014-07-02T23:59:59.000Z

    to facilitate studies of the Universe in the first billion years after the big bang in two ways. First, since they are the most luminous non-transient objects, it is possible to measure the opacity of the intergalactic medium (IGM) along the line of sight due... Digital Sky Survey (SDSS; Abazajian et al. 2009), augmented with deeper imaging from the Liverpool Telescope, its redshift was originally measured as z = 7.085 ± 0.003 from the broad ultraviolet emission lines, later refined to z = 7.0842 from a detection...

  19. A note on string size evolution in phantom cosmology

    E-Print Network [OSTI]

    Soon-Tae Hong

    2015-04-05T23:59:59.000Z

    We analyze evolution of string size in higher-dimensional cosmology with phantom field. Assuming that the Universe possesses the phantom field defined in a ten-dimensional spacetime, we predict string size which is claimed to be that of photon in nature at present. The Universe size increases as in the standard inflationary Universe model while the photon size decreases drastically at the early stage of the string evolution after the Big Bang. Moreover, the photon spin in the phantom Universe is analyzed in the framework of the stringy cosmology.

  20. Gamma-Ray Bursts from Primordial Quark Objects in Space

    E-Print Network [OSTI]

    B. Anoushirvani; D. Enström; S. Fredriksson; J. Hansson; P. Ökvist; A. Nicolaidis; S. Ekelin

    1997-11-28T23:59:59.000Z

    We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.

  1. Chaotic Friedmann-Robertson-Walker Cosmology

    E-Print Network [OSTI]

    E. Calzetta; C. El Hasi

    1992-11-23T23:59:59.000Z

    We show that the dynamics of a spatially closed Friedmann - Robertson - Walker Universe conformally coupled to a real, free, massive scalar field, is chaotic, for large enough field amplitudes. We do so by proving that this system is integrable under the adiabatic approximation, but that the corresponding KAM tori break up when non adiabatic terms are considered. This finding is confirmed by numerical evaluation of the Lyapunov exponents associated with the system, among other criteria. Chaos sets strong limitations to our ability to predict the value of the field at the Big Crunch, from its given value at the Big Bang. (Figures available on request)

  2. Fate of Yang-Mills black hole in early Universe

    SciTech Connect (OSTI)

    Nakonieczny, Lukasz; Rogatko, Marek [Institute of Physics Maria Curie-Sklodowska University 20-031 Lublin, pl. Marii Curie-Sklodowskiej 1 (Poland)

    2013-02-21T23:59:59.000Z

    According to the Big Bang Theory as we go back in time the Universe becomes progressively hotter and denser. This leads us to believe that the early Universe was filled with hot plasma of elementary particles. Among many questions concerning this phase of history of the Universe there are questions of existence and fate of magnetic monopoles and primordial black holes. Static solution of Einstein-Yang-Mills system may be used as a toy model for such a black hole. Using methods of field theory we will show that its existence and regularity depend crucially on the presence of fermions around it.

  3. New directions for gravity-wave physics via "Millikan oil drops"

    E-Print Network [OSTI]

    Raymond Y. Chiao

    2007-04-06T23:59:59.000Z

    Pairs of Planck-mass--scale drops of superfluid helium coated by electrons (i.e., "Millikan oil drops"), when levitated in the presence of strong magnetic fields and at low temperatures, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. A Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves, should be practical to perform. This would open up observations of the gravity-wave analog of the CMB from the extremely early Big Bang, and also communications directly through the interior of the Earth.

  4. The primordial explosion of a false white hole from a 5D vacuum

    E-Print Network [OSTI]

    José Edgar Madriz Aguilar; Claudia Moreno; Mauricio Bellini

    2013-12-05T23:59:59.000Z

    We explore the cosmological consequences of some possible big bang produced by a black-hole with mass $M$ in an 5D extended SdS. Under these particular circumstances, the effective 4D metric obtained by the use of a constant foliation on the extra coordinate is comported as a false white-hole (FWH), which evaporates for all unstable modes that have wavelengths bigger than the size of the FWH. Outside the white hole the repulsive gravitational field can be considered as weak, so that the dynamics for fluctuations of the inflaton field and the scalar perturbations of the metric can be linearized.

  5. "Millikan oil drops" as quantum transducers between electromagnetic and gravitational radiation

    E-Print Network [OSTI]

    Raymond Y. Chiao

    2007-02-25T23:59:59.000Z

    Pairs of Planck-mass-scale drops of superfluid helium coated by electrons (i.e., "Millikan oil drops"), when levitated in the presence of strong magnetic fields and at low temperatures, can be efficient quantum transducers between electromagnetic (EM) and gravitational (GR) radiation. A Hertz-like experiment, in which EM waves are converted at the source into GR waves, and then back-converted at the receiver from GR waves back into EM waves, should be practical to perform. This would open up observations of the gravity-wave analog of the Cosmic Microwave Background from the extremely early Big Bang, and also communications directly through the interior of the Earth.

  6. Planck Surveyor On Its Way to Orbit

    ScienceCinema (OSTI)

    None

    2010-01-08T23:59:59.000Z

    An Ariane 5 rocket carried the Planck Surveyor and a companion satellite into space May 14, 2009 from the European Space Agency (ESA) base on the northwest coast of South America. Once in orbit beyond the moon, Planck will produce the most accurate measurements ever made of the relic radiation from the big bang, plus the largest set of CMB data ever recorded. Berkeley Labs long and continuing involvement with Planck began when George Smoot of the Physics Division proposed Plancks progenitor to ESA and continues with preparations for ongoing data analysis for the U.S. Planck team at NERSC, led by Julian Borrill, co-leader of the Computational Cosmology Center

  7. From the Dark Matter Universe to the Dark Energy Universe

    E-Print Network [OSTI]

    Burra G. Sidharth

    2008-03-30T23:59:59.000Z

    Till the late nineties the accepted cosmological model was that of a Universe that had originated in the Big Bang and was now decelerating under the influence of as yet undetected dark matter, so that it would come to a halt and eventually collapse. In 1997 however, the author had put forward a contra model wherein the Universe was driven by dark energy, essentially the quantum zero point field, and was accelerating with a small cosmological constant. There were other deductions too, all in total agreement with observation. All this got confirmation in 1998 and subsequent observations have reconfirmed the findings.

  8. Quantisation of the holographic Ricci dark energy model

    E-Print Network [OSTI]

    Albarran, Imanol

    2015-01-01T23:59:59.000Z

    While general relativity is an extremely robust theory to describe the gravitational interaction in our Universe, it is expected to fail close to singularities like the cosmological ones. On the other hand, it is well known that some dark energy models might induce future singularities; this can be the case for example within the setup of the Holographic Ricci Dark Energy model (HRDE). On this work, we perform a cosmological quantisation of the HRDE model and obtain under which conditions a cosmic doomsday can be avoided within the quantum realm. We show as well that this quantum model not only avoid future singularities but also the past Big Bang.

  9. Inquiring Minds - Questions About Physics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn Other News linkThermalInnerHowAura You Wrote: I saw aBig Bang

  10. Nucleosynthesis in a Primordial Supernova: Carbon and Oxygen Abundances in SMSS J031300.36-670839.31

    E-Print Network [OSTI]

    Bessell, Michael; Keller, Stefan; Frebel, Anna; Heger, Alexander; Casey, Andrew; Masseron, Thomas; Asplund, Martin; Jacobsen, Heather; Lind, Karin; Marino, Anna; Norris, John; Yong, David; Da Costa, Gary; Chan, Conrad; Magic, Zazralt; Schmidt, Brian; Tisserand, Patrick

    2015-01-01T23:59:59.000Z

    SMSS J031300.36-670839.3 (hereafter SM0313-6708) is a sub-giant halo star, with no detectable Fe lines and large overabundances of C and Mg relative to Ca. We obtained VLT-UVES spectra extending to 3060 Angstroms showing strong OH A-X band lines enabling an oxygen abundance to be derived. The OH A-X band lines in SM0313-6708 are much stronger than the CH C-X band lines. Spectrum synthesis fits indicate an [O/C] ratio of 0.02 +- 0.175. Our high S/N UVES data also enabled us to lower the Fe abundance limit to [Fe/H]{3D},NLTE < -7.52 (3 sigma). These data support our previous suggestion that the star formed from the iron-poor ejecta of a single massive star Population III supernova.

  11. Unified Theory of Bivacuum, Particles Duality, Fields & Time. New Bivacuum Mediated Interaction, Overunity Devices, Cold Fusion & Nucleosynthesis

    E-Print Network [OSTI]

    Alex Kaivarainen

    2006-07-14T23:59:59.000Z

    New concept of Bivacuum is introduced, as a dynamic matrix of the Universe, composed from sub-quantum particles and antiparticles, forming vortical structures. These structures are presented by continuum of dipoles, each dipole containing a pair of correlated torus and antitorus: V(+) and V(-) of the opposite energy/mass, spin, charge and magnetic moments, compensating each other. The rest mass and charge of sub-elementary fermions or antifermions is a result of Bivacuum dipoles opposite symmetry shifts. Their fusion to triplets follows by elementary particles and antiparticles origination. The [corpuscle (C) - wave (W)] duality is a result of correlated beats between the 'actual' and 'complementary' states of sub-elementary fermions of triplets. It is shown, that Principle of least action, the 2d and 3d laws of thermodynamics can be a consequences of forced combinational resonance between positive and negative virtual pressure waves (VPW+/-) of Bivacuum and [C-W] pulsation of elementary particles. The quantum entanglement, mediated by virtual microtubules, composed from Bivacuum dipoles, connecting remote particles, is a result of such Bivacuum-matter interaction. The pace of time for any closed system is determined by pace of kinetic energy change of this system. The proposed mechanism of overunity devices can be provided by the electrons acceleration, induced by their resonant interaction with high frequency positive and negative VPW+/- in pull-in range conditions. The latter can be excited by pulsing currents and fields. The mechanism of overheating and cold fusion in electrolytic cells without violation of energy conservation is proposed also.

  12. Stellar evolution of low and intermediate-mass stars. IV. Hydrodynamically-based overshoot and nucleosynthesis in AGB stars

    E-Print Network [OSTI]

    F. Herwig; T. Blöcker; D. Schönberner; M. El Eid

    1997-06-12T23:59:59.000Z

    The focus of this study is on the treatment of those stellar regions immediately adjacent to convective zones. The results of hydrodynamical simulations by Freytag et al. (1996, A&A313,497) show that the motion of convective elements extends well beyond the boundary of the convectively unstable region. We have applied their parametrized description of the corresponding velocities to the treatment of overshoot in stellar evolution calculations up to the AGB (Pop.I, M_zams=3M_sun).

  13. NUCLEOSYNTHESIS IN INTERMEDIATE MASS AGB STARS JOHN LATTANZIO 1;2 , MANUEL FORESTINI 2 , CORINNE CHARBONNEL 3

    E-Print Network [OSTI]

    Lattanzio, John

    periodic thermal excursions, and the hydrogen shell overlaps the bottom of the convective envelope (in some of partial mixing of the convective envelope with carbon-enriched matter, during the dredge-up phase (Iben; the bottom of the convective envelope dips into the top of the hydrogen burning shell. This then brings

  14. SN 2006aj Associated with XRF 060218 At Late Phases: Nucleosynthesis-Signature of A Neutron Star-Driven Explosion

    E-Print Network [OSTI]

    Maeda, K; Tanaka, M; Nomoto, K; Tominaga, N; Hattori, T; Minezaki, T; Kuroda, T; Suzuki, T; Deng, J; Mazzali, P A; Pian, E; Maeda, Keiichi; Kawabata, Koji; Tanaka, Masaomi; Nomoto, Ken'ichi; Tominaga, Nozomu; Hattori, Takashi; Minezaki, Takeo; Kuroda, Takami; Suzuki, Tomoharu; Deng, Jinsong; Mazzali, Paolo A.; Pian, Elena

    2007-01-01T23:59:59.000Z

    Optical spectroscopy and photometry of SN 2006aj have been performed with the Subaru telescope at t > 200 days after GRB060218, the X-ray Flash with which it was associated. Strong nebular emission-lines with an expansion velocity of v ~ 7,300 km/s were detected. The peaked but relatively broad [OI]6300,6363 suggests the existence of ~ 2 Msun of materials in which ~1.3 Msun is oxygen. The core might be produced by a mildly asymmetric explosion. The spectra are unique among SNe Ic in (1) the absence of [CaII]7291,7324 emission, and (2) a strong emission feature at ~ 7400A, which requires ~ 0.05 Msun of newly-synthesized 58Ni. Such a large amount of stable neutron-rich Ni strongly indicates the formation of a neutron star. The progenitor and the explosion energy are constrained to 18 Msun < Mms < 22 Msun and E ~ (1 - 3) 10^{51} erg, respectively.

  15. On the Electrodynamics of Cosmic repulsion

    E-Print Network [OSTI]

    Howard D. Greyber

    2005-09-08T23:59:59.000Z

    Applying the known physics of plasmas, the 40 plus year old "Strong" Magnetic Field (SMF) model has been extended from explaining the nature of the AGN/quasar central engine, the evolution of galaxies, quasars and jets, the origin of large-scale magnetic fields and large-scale structure of galaxies in our Big Bang Universe, to explaining cosmic repulsion and why it overcame the influence of Gravity only about five billion years ago. Well-known facts about Einstein's general relativity equations, together with the SMF model, are used to explain the astronomical observations that forced us to deduce a present acceleration of the expansion of the Universe. Two groups of astronomical observers, one headed by Saul Perlmutter and the other by Robert Kirshner, recently found an amazing transition, from the expected slowing of the expansion of the Universe due to Gravity, to the expansion of the Universe beginning to be accelerated, at about an age of the Universe of nine billion years in our Big Bang Universe. Profound questions that arise are: what is this "dark energy" causing this result, and why has it started to overcome attractive gravity only in the last five billion years of our 14 billion year old Universe.

  16. Loop quantum cosmology of k=1 FRW models

    E-Print Network [OSTI]

    Abhay Ashtekar; Tomasz Pawlowski; Parampreet Singh; Kevin Vandersloot

    2007-01-23T23:59:59.000Z

    The closed, k=1, FRW model coupled to a massless scalar field is investigated in the framework of loop quantum cosmology using analytical and numerical methods. As in the k=0 case, the scalar field can be again used as emergent time to construct the physical Hilbert space and introduce Dirac observables. The resulting framework is then used to address a major challenge of quantum cosmology: resolving the big-bang singularity while retaining agreement with general relativity at large scales. It is shown that the framework fulfills this task. In particular, for states which are semi-classical at some late time, the big-bang is replaced by a quantum bounce and a recollapse occurs at the value of the scale factor predicted by classical general relativity. Thus, the `difficulties' pointed out by Green and Unruh in the k=1 case do not arise in a more systematic treatment. As in k=0 models, quantum dynamics is deterministic across the deep Planck regime. However, because it also retains the classical recollapse, in contrast to the k=0 case one is now led to a cyclic model. Finally, we clarify some issues raised by Laguna's recent work addressed to computational physicists.

  17. Inflationary Cosmology: Is Our Universe Part of a Multiverse

    SciTech Connect (OSTI)

    Guth, Alan (MIT) [MIT

    2008-11-06T23:59:59.000Z

    In 1981, Guth proposed the theory of the inflationary universe, a modification of the Big Bang theory, which is generally accepted by scientists to explain how the universe began. Nevertheless, the Big Bang theory leaves some questions, and the theory of inflation attempts to answer them. Guth states that a repulsive gravitational force generated by an exotic form of matter brought about the expansion of the universe. He postulates that the universe underwent an expansion of astronomical proportions within the first trillionth of a second of its existence, during which the seeds for its large-scale structure were generated. Guth and colleagues have further explored the possibility of mimicking inflation in a hypothetical laboratory, thereby creating a new universe, and they concluded that it might be theoretically possible. If it happened, the new universe would not endanger our own universe. Instead, it would slip through a wormhole, a hypothetical space-time travel shortcut, and rapidly disconnect from our universe. In this talk, Guth will explain the inflationary theory and review the features that make it scientifically plausible. In addition, he will discuss the biggest mystery in cosmology: Why is the value of the cosmological constant, sometimes called the "anti-gravity" effect, so remarkably small compared to theoretical expectations? Guth will explain how the inflationary theory, combined with other ideas from elementary particle physics and cosmology, can provide a possible explanation for this discrepancy.

  18. Multiverse Scenarios in Cosmology: Classification, Cause, Challenge, Controversy, and Criticism

    E-Print Network [OSTI]

    Ruediger Vaas

    2010-01-05T23:59:59.000Z

    Multiverse scenarios in cosmology assume that other universes exist "beyond" our own universe. They are an exciting challenge both for empirical and theoretical research as well as for philosophy of science. They could be necessary to understand why the big bang occurred, why (some of) the laws of nature and the values of certain physical constants are the way they are, and why there is an arrow of time. This essay clarifies competing notions of "universe" and "multiverse"; it proposes a classification of different multiverse types according to various aspects how the universes are or are not separated from each other; it reviews the main reasons for assuming the existence of other universes: empirical evidence, theoretical explanation, and philosophical arguments; and, finally, it argues that some attempts to criticize multiverse scenarios as "unscientific", insisting on a narrow understanding of falsification, is neither appropriate nor convincing from a philosophy of science point of view. -- Keywords: big bang, universe, multiverse, cosmic inflation, time, quantum gravity, string theory, laws of nature, physical constants, fine-tuning, anthropic principle, philosophy of science, metaphysics, falsificationism

  19. Magnitude-Redshift Relation for SNe Ia, Time Dilation, and Plasma Redshift

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2006-02-22T23:59:59.000Z

    We have previously shown that the type Ia supernovae data by Riess et al. match the prediction of the magnitude-redshift relation in the plasma-redshift cosmology. In this article, we also show that the recent SNLS data, which have a slightly narrower distribution as reported by Astier et al. in 2005, match the predictions of the plasma-redshift cosmology. The standard deviation of the SNLS-magnitude from the predicted curve is only about 0.14. The data indicate that there is no cosmic time dilation. The big-bang cosmology therefore appears false. The plasma redshift, which follows from exact evaluation of photons interaction with hot sparse electron plasma, leads to a quasi-static, infinite, and everlasting universe. It does not need big bang, dark energy, or dark matter for describing the observations. It predicts intrinsic redshifts of galaxies consistent with what is observed. The Hubble constant that best fits the SNLS data is about 63 km per sec per Mpc. This corresponds to an average electron density of about 0.0002 per cubic centimeter in intergalactic space. This density together with the plasma redshift heating to an average plasma temperature in intergalactic space of about 3 million K explains the observed isotropic cosmic microwave background (CMB) and the cosmic X-ray background.

  20. Plasma Redshift, Time Dilation, and Supernovas Ia

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2004-07-20T23:59:59.000Z

    The measurements of the absolute magnitudes and redshifts of supernovas Ia show that conventional physics, which includes plasma redshift, fully explains the observed magnitude-redshift relation of the supernovas. The only parameter that is required is the Hubble constant, which in principle can be measured independently. The contemporary theory of the expansion of the universe (Big Bang) requires in addition to the Hubble constant several adjustable parameters, such as an initial explosion, the dark matter parameter, and a time adjustable dark energy parameter for explaining the supernova Ia data. The contemporary Big Bang theory also requires time dilation of distant events as an inherent premise. The contention is usually that the light curves of distant supernovas show or even prove the time dilation. In the present article, we challenge this assertion. We document and show that the previously reported data in fact indicate that there is no time dilation. The data reported by Riess et al. in the Astrophysical Journal in June 2004 confirm the plasma redshift, the absence of time dilation, dark matter, and dark energy.

  1. Fluid Mechanics Explains Cosmology, Dark Matter, Dark Energy, and Life

    E-Print Network [OSTI]

    Carl H. Gibson

    2012-11-02T23:59:59.000Z

    Observations of the interstellar medium by the Herschel, Planck etc. infrared satellites throw doubt on standard {\\Lambda}CDMHC cosmological processes to form gravitational structures. According to the Hydro-Gravitational-Dynamics (HGD) cosmology of Gibson (1996), and the quasar microlensing observations of Schild (1996), the dark matter of galaxies consists of Proto-Globular-star-Cluster (PGC) clumps of Earth-mass primordial gas planets in metastable equilibrium since PGCs began star production at 0.3 Myr by planet mergers. Dark energy and the accelerating expansion of the universe inferred from SuperNovae Ia are systematic dimming errors produced as frozen gas dark matter planets evaporate to form stars. Collisionless cold dark matter that clumps and hierarchically clusters does not exist. Clumps of PGCs began diffusion from the Milky Way Proto-Galaxy upon freezing at 14 Myr to give the Magellanic Clouds and the faint dwarf galaxies of the 10^22 m diameter baryonic dark matter Galaxy halo. The first stars persist as old globular star clusters (OGCs). Water oceans and the biological big bang occurred at 2-8 Myr. Life inevitably formed and evolved in the cosmological primordial organic soup provided by 10^80 big bang planets and their hot oceans as they gently merged to form larger binary planets and small binary stars.

  2. The OOR Initiative An Update Peter Yim

    E-Print Network [OSTI]

    Baclawski, Kenneth B.

    @mitre.org>, Mike Dean , Ken Baclawski , Todd Schneider raytheon Participation Technology contributions from NCBO / Stanford-BMIR CIM Engineering (CIM3) Raytheon BBN

  3. autocrine effect orchestrating: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in Computer and Information, AT&T Labs Research Prithwish Basu, Senior Scientist, Raytheon BBN Technologies 12;AUTOMATED CLOUD RESOURCE ORCHESTRATION c COPYRIGHT 2012 Changbin...

  4. automation electronic resource: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in Computer and Information, AT&T Labs Research Prithwish Basu, Senior Scientist, Raytheon BBN Technologies 12;AUTOMATED CLOUD RESOURCE ORCHESTRATION c COPYRIGHT 2012 Changbin...

  5. automated patch-clamp technology: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    in Computer and Information, AT&T Labs Research Prithwish Basu, Senior Scientist, Raytheon BBN Technologies 12;AUTOMATED CLOUD RESOURCE ORCHESTRATION c COPYRIGHT 2012 Changbin...

  6. Channel Access over Path Segments for Ultra Low Latency MANETs

    E-Print Network [OSTI]

    Ramanathan, Ram

    ranges foretell MANETs with very large diameters. Indeed, an architecture where dense low-cost relays Cambridge, MA 02138 Email: ramanath@bbn.com Fabrice Tchakountio BBN Technologies Cambridge, MA 02138 Email and CTS frames that acquire the access rights for an entire segment toward the destination, with virtual

  7. METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. I. CONSTRAINTS ON PROGENITOR MASS AND METALLICITY OF AGB STARS UNDERGOING s-PROCESS NUCLEOSYNTHESIS

    E-Print Network [OSTI]

    Placco, Vinicius M.

    We present a comprehensive abundance analysis of two newly discovered carbon-enhanced metal-poor (CEMP) stars. HE 2138?3336 is a s-process-rich star with [Fe/H] = -2.79, and has the highest [Pb/Fe] abundance ratio measured ...

  8. Light Element Nucleosynthesis in a Molecular Cloud Interacting with a Supernova Remnant and the Origin of Beryllium-10 in the Protosolar Nebula

    E-Print Network [OSTI]

    Tatischeff, Vincent; de Séréville, Nicolas

    2014-01-01T23:59:59.000Z

    The presence of short-lived radionuclides in the early solar system provides important information about the astrophysical environment in which the solar system formed. The discovery of now extinct $^{10}$Be in calcium-aluminum-rich inclusions (CAIs) with Fractionation and Unidentified Nuclear isotope anomalies (FUN-CAIs) suggests that a baseline concentration of $^{10}$Be in the early solar system was inherited from the protosolar molecular cloud. In this paper, we first show that the $^{10}$Be recorded in FUN-CAIs cannot have been produced in situ by cosmic-ray (CR) irradiation of the FUN-CAIs themselves. We then show that trapping of Galactic CRs (GCRs) in the collapsing presolar cloud core induced a negligible $^{10}$Be contamination of the protosolar nebula. Irradiation of the presolar molecular cloud by background GCRs produced a steady-state $^{10}$Be/$^9$Be ratio ~2.3 times lower than the ratio recorded in FUN-CAIs, which suggests that the presolar cloud was irradiated by an additional source of CRs. ...

  9. Gravitinos, the Lithium problem, and DM production: Is there a corresponding neutrino physics linkage?

    E-Print Network [OSTI]

    A. W. Beckwith

    2009-06-29T23:59:59.000Z

    Studies are cited indicating that gravitino production acts as a natural upper bound to Li6 and Li7 levels, based on what happens after hadronic decay of relic 1 TeV into 100 GeV gravitinos at 1000 s. after the Big Bang. The produced gravitinos contribute a large fraction of required dark matter density. Whether or not gravitinos can be linked to neutrino production depends on which model of dark matter (DM) is assumed or used. A model presented by the author in 2008 links DM of about 100 GeV -- based on a phenomenological Lagrangian creating different Neutrino masses without SUSY -- with a dark matter candidate of about 100 GeV. This may tie in 100 GeV gravitinos with neutrino physics.

  10. Investigation of Rare Particle Production in High Energy Nuclear Collisions

    SciTech Connect (OSTI)

    None

    1999-09-02T23:59:59.000Z

    Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. We have produced the electronics and software for the STAR trigger and will begin to use these tools to search for anti-nuclei and strange hadrons when RHIC turns on later this year.

  11. Sudden gravitational transition

    SciTech Connect (OSTI)

    Caldwell, Robert R. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755 (United States); Komp, William [Physics Department, University of Louisville, 102 Natural Sciences, Louisville, Kentucky 40292 (United States); Parker, Leonard [Physics Department, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States); Vanzella, Daniel A. T. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo (IFSC-USP), Av. Trabalhador Sao-carlense, 400 Cx. Postal 369 - CEP 13560-970, Sao Carlos, Sao Paulo (Brazil)

    2006-01-15T23:59:59.000Z

    We investigate the properties of a cosmological scenario which undergoes a gravitational phase transition at late times. In this scenario, the Universe evolves according to general relativity in the standard, hot big bang picture until a redshift z < or approx. 1. Nonperturbative phenomena associated with a minimally-coupled scalar field catalyzes a transition, whereby an order parameter consisting of curvature quantities such as R{sup 2}, R{sub ab}R{sup ab}, R{sub abcd}R{sup abcd} acquires a constant expectation value. The ensuing cosmic acceleration appears driven by a dark-energy component with an equation-of-state w<-1. We evaluate the constraints from type 1a supernovae, the cosmic microwave background, and other cosmological observations. We find that a range of models making a sharp transition to cosmic acceleration are consistent with observations.

  12. Big Questions: Missing Antimatter

    ScienceCinema (OSTI)

    Lincoln, Don

    2014-08-07T23:59:59.000Z

    Einstein's equation E = mc2 is often said to mean that energy can be converted into matter. More accurately, energy can be converted to matter and antimatter. During the first moments of the Big Bang, the universe was smaller, hotter and energy was everywhere. As the universe expanded and cooled, the energy converted into matter and antimatter. According to our best understanding, these two substances should have been created in equal quantities. However when we look out into the cosmos we see only matter and no antimatter. The absence of antimatter is one of the Big Mysteries of modern physics. In this video, Fermilab's Dr. Don Lincoln explains the problem, although doesn't answer it. The answer, as in all Big Mysteries, is still unknown and one of the leading research topics of contemporary science.

  13. A modest proposal to solve the "missing mass" problem and related cosmological paradoxes

    E-Print Network [OSTI]

    J. A. Gonzalo

    2000-10-26T23:59:59.000Z

    Properly interpreted data from nearby galaxies $(z\\simeq 0.01)$ lead to $\\Omega \\simeq 0.082$. Data from farther away galaxies $(z\\simeq 1)$ with type Ia supernovae to $\\Omega =0.153$. Data to be expected from very high redshifted galaxies $(z\\simeq 10.1)$ to $\\Omega =0.500$. And actual data from the CBR, emitted at the time at which the universe became transparent $(z\\simeq 1422)$ to $\\Omega \\simeq 0.992$. All these data are simultaneously consistent with the standard big-bang picture (no inflation), in which $ \\Omega $ is time dependent and it is given by $\\Omega (y)=1/\\cosh ^{2}(y)$, being $y\\equiv \\sinh ^{-1}(T_{+}/T)^{1/2}$

  14. On the Cosmic Nuclear Cycle and the Similarity of Nuclei and Stars

    E-Print Network [OSTI]

    O. Manuel; Michael Mozina; Hilton Ratcliffe

    2005-11-18T23:59:59.000Z

    Repulsive interactions between neutrons in compact stellar cores cause luminosity and a steady outflow of hydrogen from stellar surfaces. Neutron repulsion in more massive compact objects made by gravitational collapse produces violent, energetic, cosmological events (quasars, gamma ray bursts, and active galactic centers) that had been attributed to black holes before neutron repulsion was recognized. Rather than evolving in one direction by fusion, nuclear matter on the cosmological scale cycles between fusion, gravitational collapse, and dissociation (including neutron-emission). This cycle involves neither the production of matter in an initial Big Bang nor the disappearance of matter into black holes. The similarity Bohr noted between atomic and planetary structures extends to a similarity between nuclear and stellar structures.

  15. Grand Rip and Grand Bang/Crunch cosmological singularities

    E-Print Network [OSTI]

    L. Fernández-Jambrina

    2015-01-26T23:59:59.000Z

    The present accelerated expansion of the universe has enriched the list of possible scenarios for its fate, singular or not. In this paper a unifying framework for analyzing such behaviors is proposed, based on generalized power and asymptotic expansions of the barotropic index $w$, or equivalently of the deceleration parameter $q$, in terms of the time coordinate. Besides well known singular and non-singular future behaviors, other types of strong singularities appear around the phantom divide in flat models, with features similar to those of big rip or big bang/crunch, which we have dubbed grand rip and grand bang/crunch respectively, since energy density and pressure diverge faster than $t^{-2}$ in coordinate time. In addition to this, the scale factor does not admit convergent generalized power series around these singularities with a finite number of terms with negative powers.

  16. An optical solution of Olbers' paradox

    E-Print Network [OSTI]

    V. Guruprasad

    2001-05-04T23:59:59.000Z

    Shown is that contrary to common intuition, even an arbitrarily weak attenuating mechanism is sufficient to make the background sky quite dark independently of the size of the universe and the Hubble expansion. Further shown is that such an attenuation already exists in the wave nature of light due to entrapment and diffusion from successive diffractions. This is a fundamentally new mechanism to physics, as illustrated by application to the solar neutrino attenuation, galactic dark matter and gamma ray bursts problems. It not only provides a big bang-like cutoff, but also appears to explain the appearance of primeval, metal-deficient galaxies at high redshifts, without deviating from the Olbers' premise of an infinite universe.

  17. Quantum Gravity, the Origin of Time and Time's Arrow

    E-Print Network [OSTI]

    J. W. Moffat

    1992-09-02T23:59:59.000Z

    The local Lorentz and diffeomorphism symmetries of Einstein's gravitational theory are spontaneously broken by a Higgs mechanism by invoking a phase transition in the early Universe, at a critical temperature $T_c$ below which the symmetry is restored. The spontaneous breakdown of the vacuum state generates an external time and the wave function of the Universe satisfies a time dependent Schrodinger equation, which reduces to the Wheeler-deWitt equation in the classical regime for $T T_c$ and matter is created fractions of seconds after the big bang, generating the matter in the Universe. The time direction of the vacuum expectation value of the scalar Higgs field generates a time asymmetry, which defines the cosmological arrow of time and the direction of increasing entropy as the Lorentz symmetry is restored at low temperatures.

  18. The ATLAS Experiment: Mapping the Secrets of the Universe (LBNL Summer Lecture Series)

    ScienceCinema (OSTI)

    Barnett, Michael

    2011-04-28T23:59:59.000Z

    Summer Lecture Series 2007: Michael Barnett of Berkeley Lab's Physics Division discusses the ATLAS Experiment at the European Laboratory for Particle Physics' (CERN) Large Hadron Collider. The collider will explore the aftermath of collisions at the highest energy ever produced in the lab, and will recreate the conditions of the universe a billionth of a second after the Big Bang. The ATLAS detector is half the size of the Notre Dame Cathedral and required 2000 physicists and engineers from 35 countries for its construction. Its goals are to examine mini-black holes, identify dark matter, understand antimatter, search for extra dimensions of space, and learn about the fundamental forces that have shaped the universe since the beginning of time and will determine its fate.

  19. Inflationary universe in loop quantum cosmology

    E-Print Network [OSTI]

    Xin Zhang; Yi Ling

    2007-07-23T23:59:59.000Z

    Loop quantum cosmology provides a nice solution of avoiding the big bang singularity through a big bounce mechanism in the high energy region. In loop quantum cosmology an inflationary universe is emergent after the big bounce, no matter what matter component is filled in the universe. A super-inflation phase without phantom matter will appear in a certain way in the initial stage after the bounce; then the universe will undergo a normal inflation stage. We discuss the condition of inflation in detail in this framework. Also, for slow-roll inflation, we expect the imprint from the effects of the loop quantum cosmology should be left in the primordial perturbation power spectrum. However, we show that this imprint is too weak to be observed.

  20. {Beta}-delayed neutron decay of {sup 17}C and {sup 18}C

    SciTech Connect (OSTI)

    Scheller, K.W.; Goerres, J.; Vouzoukas, S.; Wiescher, M. [Univ. of Notre Dame, South Bend, IN (United States)] [and others

    1993-10-01T23:59:59.000Z

    The {Beta}-delayed neutron decay of {sup 17}C and {sup 18}C has bear measured to investigate neutron-unbound levels in {sup 17}N and {sup 19}N. Levels of interest in {sup 17}N and {sup 18}N are those near the neutron threshold which may play a role in a astrophysical reprocess during an inhomogeneous Big Bang. Radioactive ion beaming of {sup 17}C and {sup 18}C were produced by beam fragmentation at the NSCL MSU. Ions were implanted in a plastic scintillator which served as a start detector for a time-of-flight measurement. Neutrons were detected in the MSU neutron detector array. Several neutron groups have been observed and the results will be discussed.

  1. Falsification of dark energy by fluid mechanics

    E-Print Network [OSTI]

    Gibson, Carl H

    2012-01-01T23:59:59.000Z

    The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies ...

  2. Quintessence and (anti-)Chaplygin gas in loop quantum cosmology

    SciTech Connect (OSTI)

    Lamon, Raphael; Woehr, Andreas J. [Institut fuer Theoretische Physik, Universitaet Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany)

    2010-01-15T23:59:59.000Z

    The concordance model of cosmology contains several unknown components such as dark matter and dark energy. Many proposals have been made to describe them by choosing an appropriate potential for a scalar field. We study four models in the realm of loop quantum cosmology: the Chaplygin gas, an inflationary and radiationlike potential, quintessence and an anti-Chaplygin gas. For the latter we show that all trajectories start and end with a type II singularity and, depending on the initial value, may go through a bounce. On the other hand the evolution under the influence of the first three scalar fields behaves classically at times far away from the big bang singularity and bounces as the energy density approaches the critical density.

  3. Observation of an Antimatter Hypernucleus

    SciTech Connect (OSTI)

    STAR Collaboration; Abelev, Betty

    2010-07-05T23:59:59.000Z

    Nuclear collisions recreate conditions in the universe microseconds after the Big Bang. Only a very small fraction of the emitted fragments are light nuclei, but these states are of fundamental interest. We report the observation of antihypertritons - composed of an antiproton, antineutron, and antilambda hyperon - produced by colliding gold nuclei at high energy. Our analysis yields 70 {+-} 17 antihypertritons ({sub {bar {Lambda}}}{sup 3}{bar H}) and 157 {+-} 30 hypertritons ({sub {Lambda}}{sup 3}H). The measured yields of {sub {Lambda}}{sup 3}H ({sub {bar {Lambda}}}{sup 3}{bar H}) and {sup 3}He ({sup 3}{ovr He}) are similar, suggesting an equilibrium in coordinate and momentum space populations of up, down, and strange quarks and antiquarks, unlike the pattern observed at lower collision energies. The production and properties of antinuclei, and nuclei containing strange quarks, have implications spanning nuclear/particle physics, astrophysics, and cosmology.

  4. The Evolution and Development of the Universe

    E-Print Network [OSTI]

    Clement Vidal; Charles Auffray; Alex H. Blin; Jean Chaline; Louis Crane; Thomas Durt; Borje Ekstig; Horace Fairlamb; Jan Greben; Rob Hengeveld; Francis Heylighen; Gerard Jagers op Akkerhuis; Giuseppe Longo; Nicolas F. Lori; Denis Noble; Laurent Nottale; Franc Rottiers; Stanley Salthe; John Stewart; Ruediger Vaas; Gertrudis Van de Vijver; Nico M. van Straalen

    2010-01-04T23:59:59.000Z

    This document is the Special Issue of the First International Conference on the Evolution and Development of the Universe (EDU 2008). Please refer to the preface and introduction for more details on the contributions. Keywords: acceleration, artificial cosmogenesis, artificial life, Big Bang, Big History, biological evolution, biological universe, biology, causality, classical vacuum energy, complex systems, complexity, computational universe, conscious evolution, cosmological artificial selection, cosmological natural selection, cosmology, critique, cultural evolution, dark energy, dark matter, development of the universe, development, emergence, evolution of the universe evolution, exobiology, extinction, fine-tuning, fractal space-time, fractal, information, initial conditions, intentional evolution, linear expansion of the universe, log-periodic laws, macroevolution, materialism, meduso-anthropic principle, multiple worlds, natural sciences, Nature, ontology, order, origin of the universe, particle hierarchy, philosophy, physical constants, quantum darwinism, reduction, role of intelligent life, scale relativity, scientific evolution, self-organization, speciation, specification hierarchy, thermodynamics, time, universe, vagueness.

  5. Natural Limits of Electroweak Model as Contraction of its Gauge Group

    E-Print Network [OSTI]

    Nikolay A. Gromov

    2014-10-31T23:59:59.000Z

    The low and higher energy limits of the Electroweak Model are obtained from first principles of gauge theory. Both limits are given by the same contraction of the gauge group, but for the different consistent rescalings of the field space. Mathematical contraction parameter in both cases is interpreted as energy. The very weak neutrino-matter interactions is explained by zero tending contraction parameter, which depend on neutrino energy. The second consistent rescaling corresponds to the higher energy limit of the Electroweak Model. At the infinite energy all particles lose masses, electroweak interactions become long-range and are mediated by the neutral currents. The limit model represents the development of the early Universe from the Big Bang up to the end of the first second.

  6. Doppler-like effect and doubtful expansion of universe

    E-Print Network [OSTI]

    Edward Szaraniec

    2003-10-01T23:59:59.000Z

    The distance contraction, as observed in electrical soundings over horizontally stratified earth (static system), is identified as a counterpart of Doppler shift in dynamical systems. Identification of Doppler-like effect in a stock-still systems makes it possible to give an al-ternative answer to the question about an effective cause of the Doppler shift, which sounds: the inhomogeneities. This answer opens different static as well as kinematic possibilities, which challenge established theories of expanding universe and energizing big bang.The energy propagating in stratified universe of layers exhibits a shift which could be at-tributed not only to the expansion (Hubble's theory) but alternatively to fluctuations in material properties (inhomogeneities).

  7. Protein folding and cosmology

    E-Print Network [OSTI]

    P. F. Gonzalez-Diaz; C. L. Siguenza

    1997-06-04T23:59:59.000Z

    Protein denaturing induced by supercooling is interpreted as a process where some or all internal symmetries of the native protein are spontaneously broken. Hence, the free-energy potential corresponding to a folding-funnel landscape becomes temperature-dependent and describes a phase transition. The idea that deformed vortices could be produced in the transition induced by temperature quenching, from native proteins to unfolded conformations is discussed in terms of the Zurek mechanism that implements the analogy between vortices, created in the laboratory at low energy, and the cosmic strings which are thought to have been left after symmetry breaking phase transitions in the early universe. An experiment is proposed to test the above idea which generalizes the cosmological analogy to also encompass biological systems and push a step ahead the view that protein folding is a biological equivalent of the big bang.

  8. Oak Ridge National Laboratory review: Volume 20, No. 2, 1987

    SciTech Connect (OSTI)

    Krause, C.; Zucker, A.; Corrill, L. (eds.)

    1987-01-01T23:59:59.000Z

    After a brief statement on the 1986 state of the laboratory, science highlights in collaborative research are presented: an attempt to recreate the first moments of the Big Bang, surface modification techniques in electronics, assessing home radon levels in five states, managing international integrated forest study, US-Japan joint breeder reprocessing project, optical components for SDI, evaluating the Chernobyl reactor accident, fusion superconducting magnet and fueling, scanning tunneling microscope, laser-processed solar cells, explosive trace detector, parallel computer processing algorithms, risk of fertilized egg to teratogens, trees for biomass energy, toxic waste leaching test, corn fermentation, and electricity distribution automation at Athens, TN. Milestones, other programs, the HFIR situation, book publications, and news are finally given. (DLC)

  9. Lorentzian Fuzzy Spheres

    E-Print Network [OSTI]

    Chaney, A; Stern, A

    2015-01-01T23:59:59.000Z

    We show that fuzzy spheres are solutions of ${\\it Lorentzian}$ IKKT matrix models. The commutative limit of these solutions corresponds to a sphere embedded in Minkowski space. This `sphere' has several novel features. The induced metric does not agree with the standard metric on the sphere, and moreover, it does not have a fixed signature. The curvature computed from the induced metric is not constant, has singularities at fixed latitudes (not corresponding to the poles) and is negative. The fuzzy sphere solutions serve as toy models of closed noncommutative cosmologies where big bang/crunch singularities appear only after taking the commutative limit. Perturbations are made about the solutions, and are shown to yield a scalar field theory on the sphere in the commutative limit. The scalar field can become tachyonic for a range of the parameters of the theory.

  10. Detecting dark energy with wavelets on the sphere

    E-Print Network [OSTI]

    J. D. McEwen

    2007-08-29T23:59:59.000Z

    Dark energy dominates the energy density of our Universe, yet we know very little about its nature and origin. Although strong evidence in support of dark energy is provided by the cosmic microwave background, the relic radiation of the Big Bang, in conjunction with either observations of supernovae or of the large scale structure of the Universe, the verification of dark energy by independent physical phenomena is of considerable interest. We review works that, through a wavelet analysis on the sphere, independently verify the existence of dark energy by detecting the integrated Sachs-Wolfe effect. The effectiveness of a wavelet analysis on the sphere is demonstrated by the highly statistically significant detections of dark energy that are made. Moreover, the detection is used to constrain properties of dark energy. A coherent picture of dark energy is obtained, adding further support to the now well established cosmological concordance model that describes our Universe.

  11. Color breaking in the quantum leaped stop decay

    E-Print Network [OSTI]

    Imre Czovek

    2015-04-12T23:59:59.000Z

    The superfield propagator contains a measurable quantum leap, which comes from the definition of SUSY. In the sfermion -> Goldstino + fermion vertex change: 1. the spin of sparticle with discrete 1/2, 2. the Grassman superspace with the Goldstino shift operator. 3. the spacetime as the result of extra dimensional leap. The leap nature of SUSY transformations appears in the squark decay, it is the analog definition of SUSY. The quantum leaped outgoing propagators are determined and break locally the energy and the charge. Like to the teleportation the entangled pairs are here the b quark and the Goldstino. The dominant stop production is from gluons. The stop-antistop pair decay to quantum leaped b (c or t) quark, and the decay break the color. I get for the (color breaking) quantum leap: 10^-18 m !!! And 10^-11 m color breaking would be needed for a color breaking chain reaction. The open question is: Are the colliders going to produce supersymmetry charge? Because some charges in QGP can make long color breaking and a chain reaction. A long color broken QGP state in the re-Big Bang theory could explain the near infinite energy and the near infinite mass of the universe: - at first was random color QGP in the flat space-time, - at twice the color restoration in the curved space-time, which eats the Goldstinos, - and finally the baryon genesis. The re Big Bang make a supernova like collapse and a flat explosion of Universe. This explanation of SUSY hides the Goldstone fermion in the extra dimensions, the Goldstino propagate only in superspace and it is a not observable dark matter. PACS: 12.60.Jv

  12. A classification of spherically symmetric self-similar dust models

    E-Print Network [OSTI]

    B. J. Carr

    2000-03-02T23:59:59.000Z

    We classify all spherically symmetric dust solutions of Einstein's equations which are self-similar in the sense that all dimensionless variables depend only upon $z\\equiv r/t$. We show that the equations can be reduced to a special case of the general perfect fluid models with equation of state $p=\\alpha \\mu$. The most general dust solution can be written down explicitly and is described by two parameters. The first one (E) corresponds to the asymptotic energy at large $|z|$, while the second one (D) specifies the value of z at the singularity which characterizes such models. The E=D=0 solution is just the flat Friedmann model. The 1-parameter family of solutions with z>0 and D=0 are inhomogeneous cosmological models which expand from a Big Bang singularity at t=0 and are asymptotically Friedmann at large z; models with E>0 are everywhere underdense relative to Friedmann and expand forever, while those with E0 ones. The 2-parameter solutions with D>0 again represent inhomogeneous cosmological models but the Big Bang singularity is at $z=-1/D$, the Big Crunch singularity is at $z=+1/D$, and any particular solution necessarily spans both z0. While there is no static model in the dust case, all these solutions are asymptotically ``quasi-static'' at large $|z|$. As in the D=0 case, the ones with $E \\ge 0$ expand or contract monotonically but the latter may now contain a naked singularity. The ones with E<0 expand from or recollapse to a second singularity, the latter containing a black hole.

  13. The Conformal Universe III: Basic Mechanisms of Matter Generation

    E-Print Network [OSTI]

    Renato Nobili

    2014-12-22T23:59:59.000Z

    This is the last of three papers on Conformal General Relativity (CGR), which describes inflation as a process primed by the spontaneous breakdown of a conformal-symmetric instable vacuum and the big bang as a sudden transfer of energy from geometry to matter. This process is driven by the interaction of a ghost scalar field $\\sigma$, called the {\\em dilation field}, with a scalar field $\\varphi$ behaving as a Higgs field of varying mass. Inflation ends when the interaction potential vanishes and $\\sigma,\\varphi$ amplitudes converge to their expectation values in a stable vacuum. Explicit solutions of $\\sigma, \\varphi$ dynamics in the semiclassical approximation are exemplified by numerical simulations. In order that the theory may survive quantization, the perfect vanishing of the total zero-point energy density of all involved fields must be postulated, which is equivalent to extending the correspondence principle of Bohr to quantum field theory. Since inflation actually is an adiabatic thermodynamic process, the temperature $T_B\\simeq 142$\\,GeV and the effective degeneracy $g_{*s}(T_B)\\simeq 0.887$ of Higgs-boson entropy at big bang are easily found. The application of entropy-conservation property then results in striking predictions. In particular, given the Higg-boson mass $\\mu_H\\simeq 126.5$ GeV and self-coupling constant $\\lambda\\simeq 0.132$, and the temperature $T_{BK}= 2.35\\times 10^{-13}$ and effective entropy degeneracy $g_{*s}(T_{BK})\\simeq 3.91$ of the current cosmic-background radiation, the cosmological constant $\\rho_{\\hbox{vac}}\\simeq 6.91\\times 10^{-47}$GeV$^4$ and expansion factor across inflation $F\\simeq 1.32\\times 10^{27}$ are predicted.

  14. PROTECTING APPLICATIONS AGAINST MALICE USING ADAPTIVE MIDDLEWARE

    E-Print Network [OSTI]

    Schmidt, Douglas C.

    that protect critical infrastructure, such as power grids, telecommunications, air transportation, fwebber, ppal, jloyall}@bbn.com Douglas C. Schmidt Electrical & Computer Engineering Department Henry dependent on the common information technology (IT) infrastructure used to build distributed applications

  15. Proceedings of the First Workshop on Applying NLP Tools to Similar Languages, Varieties and Dialects, pages 6875, Dublin, Ireland, August 23 2014.

    E-Print Network [OSTI]

    then be mined for terms of interest. Raytheon's BBN Broadcast Monitoring System is an example of such a system (Raytheon, 2012). One liability of this approach is the need to establish the vocabulary, upon which

  16. From SupernovaeFrom Supernovae to Inflationto Inflation

    E-Print Network [OSTI]

    Yamamoto, Hirosuke

    From SupernovaeFrom Supernovae to Inflationto Inflation Katsuhiko SatoKatsuhiko Sato 1)Department.4. NucleosynthesisNucleosynthesis in supernovaein supernovae II.II. ParticleParticle cosmologycosmology andand Early

  17. CRD Report

    E-Print Network [OSTI]

    Wang, Ucilia

    2006-01-01T23:59:59.000Z

    of supernovae, gamma ray bursts and nucleosynthesis. “HighBlack Holes to Gamma Ray Bursts. ” A book launch party is

  18. Is Cosmological Constant Needed in Higgs Inflation?

    E-Print Network [OSTI]

    Feng, Chao-Jun

    2014-01-01T23:59:59.000Z

    The detection of B-mode shows a very powerful constraint to theoretical inflation models through the measurement of the tensor-to-scalar ratio $r$. Higgs boson is the most likely candidate of the inflaton field. But usually, Higgs inflation models predict a small value of $r$, which is not quite consistent with the recent results from BICEP2. In this paper, we explored whether a cosmological constant energy component is needed to improve the situation. And we found the answer is yes. For the so-called Higgs chaotic inflation model with a quadratic potential, it predicts $r\\approx 0.2$, $n_s\\approx0.96$ with e-folds number $N\\approx 56$, which is large enough to overcome the problems such as the horizon problem in the Big Bang cosmology. The required energy scale of the cosmological constant is roughly $\\Lambda \\sim (10^{14} \\text{GeV})^2 $, which means a mechanism is still needed to solve the fine-tuning problem in the later time evolution of the universe, e.g. by introducing some dark energy component.

  19. Is Cosmological Constant Needed in Higgs Inflation?

    E-Print Network [OSTI]

    Chao-Jun Feng; Xin-Zhou Li

    2014-04-15T23:59:59.000Z

    The detection of B-mode shows a very powerful constraint to theoretical inflation models through the measurement of the tensor-to-scalar ratio $r$. Higgs boson is the most likely candidate of the inflaton field. But usually, Higgs inflation models predict a small value of $r$, which is not quite consistent with the recent results from BICEP2. In this paper, we explored whether a cosmological constant energy component is needed to improve the situation. And we found the answer is yes. For the so-called Higgs chaotic inflation model with a quadratic potential, it predicts $r\\approx 0.2$, $n_s\\approx0.96$ with e-folds number $N\\approx 56$, which is large enough to overcome the problems such as the horizon problem in the Big Bang cosmology. The required energy scale of the cosmological constant is roughly $\\Lambda \\sim (10^{14} \\text{GeV})^2 $, which means a mechanism is still needed to solve the fine-tuning problem in the later time evolution of the universe, e.g. by introducing some dark energy component.

  20. Heavy Ion Collisions: Achievements and Challenges

    E-Print Network [OSTI]

    Edward Shuryak

    2014-12-29T23:59:59.000Z

    A decade ago brief summary of the field could be formulated as a discovery of strongly-coupled QGP, making a very good liquid with surprisingly small viscosity. Since 2010 we have LHC program, which added a lot to our understanding, and now there seems to be a need to consolidate what we learned and formulate a list of issues to be studied next. Among those is understanding of how small a system can be, while still displaying collective/hydrodynamics behavior. This issue is of course coupled to more general questions about out-of-equilibrium stage of the collisions, and mechanisms/time of equilibration, in weak and strong coupling. Hydrodynamical perturbations, leading to higher harmonics of angular correlations, are identified as long-lived sound waves. Recently studied reactions involving sounds include phonon decays into two ("loop viscosity"), phonon+magnetic field into photons/dileptons (sono-magneto-luminescence), and two phonons into a gravity wave, a penetrating probe of the Big Bang.

  1. Observational evidence favors a static universe

    E-Print Network [OSTI]

    David F. Crawford

    2014-07-09T23:59:59.000Z

    The common attribute of all Big Bang cosmologies is that they are based on the assumption that the universe is expanding. However examination of the evidence for this expansion clearly favours a static universe. The major topics considered are: Tolman surface brightness, angular size, type 1a supernovae, gamma ray bursts, galaxy distributions, quasar distributions, X-ray background radiation, cosmic microwave background radiation, radio source counts, quasar variability and the Butcher--Oemler effect. An analysis of the best raw data for these topics shows that they are consistent with expansion only if there is evolution that cancels the effects of expansion. An alternate cosmology, curvature cosmology, is in full agreement with the raw data. This tired-light cosmology predicts a well defined static and stable universe and is fully described. It not only predicts accurate values for the Hubble constant and the temperature of cosmic microwave background radiation but shows excellent agreement with most of the topics considered. Curvature cosmology also predicts the deficiency in solar neutrino production rate and can explain the anomalous acceleration of {\\it Pioneer} 10.

  2. Analogue models for FRW cosmologies

    E-Print Network [OSTI]

    Carlos Barcelo; Stefano Liberati; Matt Visser

    2003-05-16T23:59:59.000Z

    It is by now well known that various condensed matter systems may be used to mimic many of the kinematic aspects of general relativity, and in particular of curved-spacetime quantum field theory. In this essay we will take a look at what would be needed to mimic a cosmological spacetime -- to be precise a spatially flat FRW cosmology -- in one of these analogue models. In order to do this one needs to build and control suitable time dependent systems. We discuss here two quite different ways to achieve this goal. One might rely on an explosion, physically mimicking the big bang by an outflow of whatever medium is being used to carry the excitations of the analogue model, but this idea appears to encounter dynamical problems in practice. More subtly, one can avoid the need for any actual physical motion (and avoid the dynamical problems) by instead adjusting the propagation speed of the excitations of the analogue model. We shall focus on this more promising route and discuss its practicality.

  3. Deuterium at High Redshifts: Recent Advances and Open Issues

    E-Print Network [OSTI]

    Max Pettini

    2006-01-19T23:59:59.000Z

    Among the light elements created in the Big Bang, deuterium is one of the most difficult to detect but is also the one whose abundance depends most sensitively on the density of baryons. Thus, although we still have only a few positive identifications of D at high redshifts--when the D/H ratio was close to its primordial value--they give us the most reliable determination of the baryon density, in excellent agreement with measures obtained from entirely different probes, such as the anisotropy of the cosmic microwave background temperature and the average absorption of the UV light of quasars by the intergalactic medium. In this review, I relate observations of D/H in distant gas clouds to the large body of data on the local abundance of D obtained in the last few years with the FUSE satellite. I also discuss some of the outstanding problems in light element abundances and consider future prospects for advances in this area.

  4. The Hubble series: Convergence properties and redshift variables

    E-Print Network [OSTI]

    Celine Cattoen; Matt Visser

    2007-10-10T23:59:59.000Z

    In cosmography, cosmokinetics, and cosmology it is quite common to encounter physical quantities expanded as a Taylor series in the cosmological redshift z. Perhaps the most well-known exemplar of this phenomenon is the Hubble relation between distance and redshift. However, we now have considerable high-z data available, for instance we have supernova data at least back to redshift z=1.75. This opens up the theoretical question as to whether or not the Hubble series (or more generally any series expansion based on the z-redshift) actually converges for large redshift? Based on a combination of mathematical and physical reasoning, we argue that the radius of convergence of any series expansion in z is less than or equal to 1, and that z-based expansions must break down for z>1, corresponding to a universe less than half its current size. Furthermore, we shall argue on theoretical grounds for the utility of an improved parameterization y=z/(1+z). In terms of the y-redshift we again argue that the radius of convergence of any series expansion in y is less than or equal to 1, so that y-based expansions are likely to be good all the way back to the big bang y=1, but that y-based expansions must break down for y<-1, now corresponding to a universe more than twice its current size.

  5. Chemical Elements at High and Low Redshifts

    E-Print Network [OSTI]

    Max Pettini

    2006-03-02T23:59:59.000Z

    The past few years have seen a steady progress in the determination of element abundances at high redshifts, with new and more accurate measures of metallicities in star-forming galaxies, in QSO absorbers, and in the intergalactic medium. We have also become more aware of the limitations of the tools at our disposal in such endeavours. I summarise these recent developments and--in tune with the theme of this meeting--consider the clues which chemical abundance studies offer to the links between the high redshift galaxy populations and today's galaxies. The new data are `fleshing out' the overall picture of element abundances at redshifts z = 2 - 3 which has been gradually coming into focus over the last decade. In particular, we can now account for at least 40% of the metals produced by the global star formation activity in the universe from the Big Bang to z = 2.5, and we have strong indications of where the remainder are likely to be found.

  6. Beryllium in the Ultra-Lithium-Deficient,Metal-Poor Halo Dwarf, G186-26

    E-Print Network [OSTI]

    Ann Merchant Boesgaard; Megan C. Novicki

    2005-09-16T23:59:59.000Z

    The vast majority of low-metal halo dwarfs show a similar amount of Li; this has been attributed to the Li that was produced in the Big Bang. However, there are nine known halo stars with T $>$ 5900 K and [Fe/H] $<$ $-$1.0 that are ultra-Li-deficient. We have looked for Be in the very low metallicity star, G 186-26 at [Fe/H] = $-$2.71, which is one of the ultra-Li-deficient stars. This star is also ultra-Be deficient. Relative to Be in the Li-normal stars at [Fe/H] = $-$2.7, G 182-26 is down in Be by more than 0.8 dex. Of two potential causes for the Li-deficiency -- mass-transfer in a pre-blue straggler or extra rotationally-induced mixing in a star that was initially a very rapid rotator -- the absence of Be favors the blue-straggler hypothesis, but the rotation model cannot be ruled-out completely.

  7. Hydro-Gravitational-Dynamics Interpretation of the Tadpole VV29 Merging Galaxy System: Dark-Matter-Halo-Planet Star-Cluster Wakes

    E-Print Network [OSTI]

    Carl H. Gibson

    2008-03-29T23:59:59.000Z

    Hubble Space telescope (HST) images of merging galaxy system VV29 reveal the 0.3 Mpc baryonic-dark-matter (BDM) halo composed of primordial protoglobularstarcluster (PGC) clumps of planets. Star-cluster-wakes trace the merger by formation of stars from the planets. Aligned young globular star clusters (YGCs), star-wakes and dust-trails show the frictional, spiral passage of galaxy fragments VV29cdef in a long tail-like galaxy (VV29b) as the fragments merge on the accretion disk plane of the central spiral galaxy VV29a. The observations confirm the hydro-gravitational-dynamics (HGD) prediction of Gibson 1996 and quasar microlensing inference of Schild 1996 that the dark matter of galaxies is dominated by planets (PFPs) in million-solar-mass clumps. Globular star clusters (YGCs, OGCs, PGCs) preserve the density of the plasma epoch 30,000 years after the big bang when viscous supercluster-fragmentation began. Tadpole images show linear galaxy clusters reflecting turbulent vortex lines of protogalaxy fragmentation at the 0.003 Mpc Kolmogorov-Nomura scale of the plasma before transition to gas. The halo size indicates strong diffusion of PGC primordial-planet-clumps from a cooling protogalaxy as its planets freeze.

  8. High Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z~6 QSOs

    E-Print Network [OSTI]

    Robert A. Simcoe

    2006-05-30T23:59:59.000Z

    New measurements of the z~6 intergalactic CIV abundance are presented, using moderate resolution IR spectra of two QSOs taken with GNIRS on Gemini South. These data were systematically searched for high redshift CIV absorption lines, using objective selection criteria. Comprehensive tests were performed to quantify sample incompleteness, as well as the rate of false positive CIV identifications. The trend of constant $\\Omega_{CIV}(z)$ observed at z~2-5 appears to continue to z~6, the highest observed redshift. The CIV sample is also consistent with the redshift-invariant form of the CIV column density distribution reported by Songaila (2001) at lower redshift, although with fairly large uncertainties due to a smaller sample size and noisier infrared data. The constant value of $\\Omega_{CIV}$ does not necessarily imply that the IGM was infused with an early metallicity ``floor,'' but the presence of early CIV does indicate that heavy-element enrichment began < 1 Gyr after the Big Bang. The lack of a decline in $\\Omega_{CIV}$ at high redshift may indicate that integrated CIV measurements are sensitive to the instantaneous rate of feedback from galaxy formation at each epoch. Alternatively, it could result from a balance in the evolution of the intergalactic gas density, ionization conditions, and heavy-element abundance over time.

  9. Observing the Inflationary Reheating

    E-Print Network [OSTI]

    Jerome Martin; Christophe Ringeval; Vincent Vennin

    2014-10-29T23:59:59.000Z

    Reheating is the the epoch which connects inflation to the subsequent hot Big-Bang phase. Conceptually very important, this era is however observationally poorly known. We show that the current Planck satellite measurements of the Cosmic Microwave Background (CMB) anisotropies constrain the kinematic properties of the reheating era for most of the inflationary models. This result is obtained by deriving the marginalized posterior distributions of the reheating parameter for about 200 models taken in Encyclopaedia Inflationaris. Weighted by the statistical evidence of each model to explain the data, we show that the Planck 2013 measurements induce an average reduction of the posterior-to-prior volume by 40%. Making some additional assumptions on reheating, such as specifying a mean equation of state parameter, or focusing the analysis on peculiar scenarios, can enhance or reduce this constraint. Our study also indicates that the Bayesian evidence of a model can substantially be affected by the reheating properties. The precision of the current CMB data is therefore such that estimating the observational performance of a model now requires to incorporate information about its reheating history.

  10. The Revival of White Holes as Small Bangs

    E-Print Network [OSTI]

    Alon Retter; Shlomo Heller

    2011-07-17T23:59:59.000Z

    Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact time reversal of black holes, therefore they should continuously throw away material. It is accepted, however, that a persistent ejection of mass leads to gravitational pressure, the formation of a black hole and thus to the "death of while holes". So far, no astronomical source has been successfully tagged a white hole. The only known white hole is the Big Bang which was instantaneous rather than continuous or long-lasting. We thus suggest that the emergence of a white hole, which we name a 'Small Bang', is spontaneous - all the matter is ejected at a single pulse. Unlike black holes, white holes cannot be continuously observed rather their effect can only be detected around the event itself. Gamma ray bursts are the most energetic explosions in the universe. Long gamma-ray bursts were connected with supernova eruptions. There is a new group of gamma-ray bursts, which are relatively close to Earth, but surprisingly lack any supernova emission. We propose identifying these bursts with white holes. White holes seem like the best explanation of gamma-ray bursts that appear in voids. We also predict the detection of rare gigantic gamma-ray bursts with energies much higher than typically observed.

  11. Macroscopic theory of dark sector

    E-Print Network [OSTI]

    Boris E. Meierovich

    2014-10-06T23:59:59.000Z

    A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Massive fields {\\phi}_{I} with {\\phi}^{K}{\\phi}_{K}0 describe two different forms of dark matter. The space-like ({\\phi}^{K}{\\phi}_{K}0) massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating non-singular scenarios of evolution of the universe. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerate expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the boundary of existence of regular oscillating solutions in the absence of vector fields. The simplicity of the general covariant expression for the energy-momentum tensor allows to display the main properties of the dark sector analytically and avoid unnecessary model assumptions.

  12. Elliptic Flow: A Brief Review

    E-Print Network [OSTI]

    Raimond Snellings

    2011-06-15T23:59:59.000Z

    One of the fundamental questions in the field of subatomic physics is what happens to matter at extreme densities and temperatures as may have existed in the first microseconds after the Big Bang and exists, perhaps, in the core of dense neutron stars. The aim of heavy-ion physics is to collide nuclei at very high energies and thereby create such a state of matter in the laboratory. The experimental program started in the 1990's with collisions made available at the Brookhaven Alternating Gradient Synchrotron (AGS), the CERN Super Proton Synchrotron (SPS) and continued at the Brookhaven Relativistic Heavy-Ion Collider (RHIC) with maximum center of mass energies of 4.75, 17.2 and 200 GeV respectively. Collisions of heavy-ions at the unprecedented energy of 2.76 TeV have recently become available at the LHC collider at CERN. In this review I will give a brief introduction to the physics of ultra-relativistic heavy-ion collisions and discuss the current status of elliptic flow measurements.

  13. Horava–Lifshitz cosmology, entropic interpretation and quark–hadron phase transition

    SciTech Connect (OSTI)

    Kheyri, F., E-mail: F_Kheyri@sbu.ac.ir; Khodadi, M., E-mail: M.Khodadi@sbu.ac.ir; Sepangi, Hamid Reza, E-mail: hr-sepangi@sbu.ac.ir

    2013-05-15T23:59:59.000Z

    Based on the assumptions of the standard model of cosmology, a phase transition associated with chiral symmetry breaking after the electroweak transition has occurred at approximately 10 ?s after the Big Bang to convert a plasma of free quarks and gluons into hadrons. We consider such a phase transition in the context of a deformed Horava–Lifshitz cosmology. The Friedmann equation for the deformed Horava–Lifshitz universe is obtained using the entropic interpretation of gravity, proposed by Verlinde. We investigate the effects of the parameter ? appearing in the theory on the evolution of the physical quantities relevant to a description of the early universe, namely, the energy density and temperature before, during and after the phase transition. Finally, we study the cross-over phase transition in both high and low temperature regions in view of the recent lattice QCD simulations data. -- Highlights: ? We study the problem of the quark–hadron phase transition in the early universe, in the context of Horava–Lifshitz cosmology. ? We conduct this study by including the recently introduced entropic principle. ? We study the behavior of thermodynamical parameters of the theory.

  14. QCD Phase Transition in Brans-Dicke DGP model of Brane Gravity

    E-Print Network [OSTI]

    T. Golanbari; A. Mohammadi; Kh. Saaidi

    2014-08-24T23:59:59.000Z

    A DGP brane-world model with a perfect fluid brane matter including a Brans-Dicke (BD) scalar field on brane has been utilized to investigate the problem of quark-hadron phase (QHP) transition in early times of the Universe evoltion. The presence of BD scalar field came up with some modification terms in the Friedmann equation, however we have a usual form of conservation equation for brane matter since scalar field only has a non-mnimally interaction with geometry. Behavior of phase transition strongly depends on the basic evolution equations. Then, even a small change in these relation might come to interesting results about the time of transition. Two different formalisms as smooth crossover formalism in which lattice QCD data is used for obtaining the matter equation of state and first-order phase transition formalism, have been used to investigate of the evolution of physical quatities relevant to quantitative of early times such as energy density $\\rho$, scale factor $a$, and temperature $T$. The obtained results show that the general behavior of temperature is similar in both of two formalisms and the QHP transition occurred at about micro-second after the Big Bang.

  15. FRW-type cosmologies with adiabatic matter creation

    SciTech Connect (OSTI)

    Lima, J.A. [Physics Department, Brown University, Providence, Rhode Island 02912 (United States)] [Physics Department, Brown University, Providence, Rhode Island 02912 (United States); [Departamento de Fisica Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Germano, A.S. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil)] [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Abramo, L.R. [Physics Department, Brown University, Providence, Rhode Island 02912 (United States)] [Physics Department, Brown University, Providence, Rhode Island 02912 (United States)

    1996-04-01T23:59:59.000Z

    Some properties of cosmological models with matter creation are investigated in the framework of the Friedmann-Robertson-Walker line element. For adiabatic matter creation, as developed by Prigogine and co-workers, we derive a simple expression relating the particle number density {ital n} and energy density {rho} which holds regardless of the matter creation rate. The conditions to generate inflation are discussed and by considering the natural phenomenological matter creation rate {psi}=3{beta}{ital nH}, where {beta} is a pure number of the order of unity and {ital H} is the Hubble parameter, a minimally modified hot big-bang model is proposed. The dynamic properties of such models can be deduced from the standard ones simply by replacing the adiabatic index {gamma} of the equation of state by an effective parameter {gamma}{sub {asterisk}}={gamma}(1{minus}{beta}). The thermodynamic behavior is determined and it is also shown that ages large enough to agree with observations are obtained even given the high values of {ital H} suggested by recent measurements. {copyright} {ital 1996 The American Physical Society.}

  16. Le LHC, un tunnel cosmique

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d?autres termes, qu?est-ce que le LHC peut nous apporter dans la connaissance de l?Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l?univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l?Univers ? La matière noire est-elle détectable au LHC ? L?énergie noire ? Pourquoi l?antimatière accumulée au CERN est-elle si rare dans l?Univers ? Et si le CERN a bâti sa réputation sur l?exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l?évolution cosmique ? Depuis une trentaine d?années, notre compréhension de l?univers dans ses plus grandes dimensions et l?appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

  17. Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Slosar, A.; Arnold, K.; Austermann, J.; Benson, B. A.; Bischoff, C.; Bock, J.; Bond, J. R.; Borrill, J.; Calabrese, E.; Carlstrom, J. E.; Carvalho, C. S.; Chang, C. L.; Chiang, H. C.; Church, S.; Cooray, A.; Crawford, T. M.; Dawson, K. S.; Das, S.; Devlin, M. J.; Dobbs, M.; Dodelson, S.; Dore, O.; Dunkley, J.; Errard, J.; Fraisse, A.; Gallicchio, J.; Halverson, N. W.; Hanany, S.; Hildebrandt, S. R.; Hincks, A.; Hlozek, R.; Holder, G.; Holzapfel, W. L.; Honscheid, K.; Hu, W.; Hubmayr, J.; Irwin, K.; Jones, W. C.; Kamionkowski, M.; Keating, B.; Keisler, R.; Knox, L.; Komatsu, E.; Kovac, J.; Lawrence, C.; Lee, A. T.; Leitch, E.; Linder, E.; Lubin, P.; McMahon, J.; Miller, A.; Newburgh, L.; Niemack, M. D.; Nguyen, H.; Nguyen, H. T.; Page, L.; Pryke, C.; Reichardt, C. L.; Ruhl, J. E.; Sehgal, N.; Seljak, U.; Sievers, J.; Silverstein, E.; Smith, K. M.; Spergel, D.; Staggs, S. T.; Stark, A.; Stompor, R.; Vieregg, A. G.; Wang, G.; Watson, S.; Wollack, E. J.; Wu, W. L.K.; Yoon, K. W.; Zahn, O.; Kuo, C. -L.

    2015-03-01T23:59:59.000Z

    This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve ? (?mv) = 16 meV and ? (Neff)(Neff) = 0.020. Such a mass measurement will produce a high significance detection of non-zero ?m??m?, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics — the origin of mass. This precise a measurement of Neff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that Neff = 3.046.

  18. Extremely metal-poor gas at a redshift of 7

    E-Print Network [OSTI]

    Simcoe, Robert A; Cooksey, Kathy L; Kao, Melodie M; Matejek, Michael S; Burgasser, Adam J; 10.1038/nature11612

    2012-01-01T23:59:59.000Z

    In typical astrophysical environments, the abundance of heavy elements ranges from 0.001 to 2 times the solar concentration. Lower abundances have been seen in select stars in the Milky Way's halo and in two quasar absorption systems at redshift z=3. These are widely interpreted as relics from the early universe, when all gas possessed a primordial chemistry. Before now there have been no direct abundance measurements from the first Gyr after the Big Bang, when the earliest stars began synthesizing elements. Here we report observations of hydrogen and heavy element absorption in a quasar spectrum at z=7.04, when the universe was just 772 Myr old (5.6% its present age). We detect a large column of neutral hydrogen but no corresponding heavy elements, limiting the chemical abundance to less than 1/10,000 the solar level if the gas is in a gravitationally bound protogalaxy, or less than 1/1,000 solar if it is diffuse and unbound. If the absorption is truly intergalactic, it would imply that the universe was neit...

  19. The Formation of the First Low-Mass Stars From Gas With Low Carbon and Oxygen Abundances

    E-Print Network [OSTI]

    Bromm, V; Bromm, Volker; Loeb, Abraham

    2003-01-01T23:59:59.000Z

    The first stars in the Universe are predicted to have been much more massive than the Sun. Gravitational condensation accompanied by cooling of the primordial gas due to molecular hydrogen, yields a minimum fragmentation scale of a few hundred solar masses. Numerical simulations indicate that once a gas clump acquires this mass, it undergoes a slow, quasi-hydrostatic contraction without further fragmentation. Here we show that as soon as the primordial gas - left over from the Big Bang - is enriched by supernovae to a carbon or oxygen abundance as small as ~0.01-0.1% of that found in the Sun, cooling by singly-ionized carbon or neutral oxygen can lead to the formation of low-mass stars. This mechanism naturally accommodates the discovery of solar mass stars with unusually low (10^{-5.3} of the solar value) iron abundance but with a high (10^{-1.3} solar) carbon abundance. The minimum stellar mass at early epochs is partially regulated by the temperature of the cosmic microwave background. The derived critical...

  20. The Formation of the First Low-Mass Stars From Gas With Low Carbon and Oxygen Abundances

    E-Print Network [OSTI]

    Volker Bromm; Abraham Loeb

    2003-10-21T23:59:59.000Z

    The first stars in the Universe are predicted to have been much more massive than the Sun. Gravitational condensation accompanied by cooling of the primordial gas due to molecular hydrogen, yields a minimum fragmentation scale of a few hundred solar masses. Numerical simulations indicate that once a gas clump acquires this mass, it undergoes a slow, quasi-hydrostatic contraction without further fragmentation. Here we show that as soon as the primordial gas - left over from the Big Bang - is enriched by supernovae to a carbon or oxygen abundance as small as ~0.01-0.1% of that found in the Sun, cooling by singly-ionized carbon or neutral oxygen can lead to the formation of low-mass stars. This mechanism naturally accommodates the discovery of solar mass stars with unusually low (10^{-5.3} of the solar value) iron abundance but with a high (10^{-1.3} solar) carbon abundance. The minimum stellar mass at early epochs is partially regulated by the temperature of the cosmic microwave background. The derived critical abundances can be used to identify those metal-poor stars in our Milky Way galaxy with elemental patterns imprinted by the first supernovae.

  1. Geometry of Majorana neutrino and new symmetries

    E-Print Network [OSTI]

    G. G. Volkov

    2006-07-30T23:59:59.000Z

    Experimental observation of Majorana fermion matter gives a new impetus to the understanding of the Lorentz symmetry and its extension, the geometrical properties of the ambient space-time structure, matter--antimatter symmetry and some new ways to understand the baryo-genesis problem in cosmology. Based on the primordial Majorana fermion matter assumption, we discuss a possibility to solve the baryo-genesis problem through the the Majorana-Diraco genesis in which we have a chance to understand creation of Q(em) charge and its conservation in our D=1+3 Universe after the Big Bang. In the Majorana-Diraco genesis approach there appears a possibility to check the proton and electron non-stability on the very low energy scale. In particle physics and in our space-time geometry, the Majorana nature of the neutrino can be related to new types of symmetries which are lying beyond the binary Cartan-Killing-Lie algebras/superalgebras. This can just support a conjecture about the non-completeness of the SM in terms of binary Cartan--Killing--Lie symmetries/supersymmetries. As one of the very important applications of such new ternary symmetries could be related with explanation of the nature of the three families and three colour symmetry. The Majorana neutrino can directly indicate the existence of a new extra-dimensional geometry and thanks to new ternary space-time symmetries, could lead at high energies to the unextraordinary phenomenological consequences.

  2. B2FH, the Cosmic Microwave Background and Cosmology

    E-Print Network [OSTI]

    G. Burbidge

    2008-07-24T23:59:59.000Z

    In this talk I shall start by describing how we set about and carried out the work which led to the publication of B2FH in 1957. I then shall try and relate this work and the circumstances that surrounded it to the larger problem of the origin and formation of the universe. Here it is necessary to look back at the way that ideas developed and how in many situations astronomers went astray. Of course this is a personal view, though I very strongly believe that if he were still here, it is the approach that Fred Hoyle would take. I start by describing the problems originally encountered by Gamow and his associates in trying to decide where the helium was made. This leads me to a modern discussion of the origin of 2D, 3He, 4He and 7Li, originally described by B2FH as due to the x-process. While it is generally argued, following Gamow, Alpher, and Herman, that these isotopes were synthesized in a big bang I shall show that it is equally likely that these isotopes were made in active galactic nuclei, as was the cosmic microwave background (CMB), in a cyclic universe model. The key piece of observational evidence is that the amount of energy carried by the CMB, namely about 4.5 x 10-13 erg cm-3

  3. Boltzmann brains and the scale-factor cutoff measure of the multiverse

    SciTech Connect (OSTI)

    De Simone, Andrea; Guth, Alan H. [Center for Theoretical Physics, Laboratory for Nuclear Science, and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Linde, Andrei [Department of Physics, Stanford University, Stanford, California 94305 (United States); Yukawa Institute of Theoretical Physics, Kyoto University, Kyoto (Japan); Noorbala, Mahdiyar [Department of Physics, Stanford University, Stanford, California 94305 (United States); Salem, Michael P.; Vilenkin, Alexander [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)

    2010-09-15T23:59:59.000Z

    To make predictions for an eternally inflating 'multiverse', one must adopt a procedure for regulating its divergent spacetime volume. Recently, a new test of such spacetime measures has emerged: normal observers - who evolve in pocket universes cooling from hot big bang conditions - must not be vastly outnumbered by 'Boltzmann brains' - freak observers that pop in and out of existence as a result of rare quantum fluctuations. If the Boltzmann brains prevail, then a randomly chosen observer would be overwhelmingly likely to be surrounded by an empty world, where all but vacuum energy has redshifted away, rather than the rich structure that we observe. Using the scale-factor cutoff measure, we calculate the ratio of Boltzmann brains to normal observers. We find the ratio to be finite, and give an expression for it in terms of Boltzmann brain nucleation rates and vacuum decay rates. We discuss the conditions that these rates must obey for the ratio to be acceptable, and we discuss estimates of the rates under a variety of assumptions.

  4. The characteristic black hole mass resulting from direct collapse in the early universe

    E-Print Network [OSTI]

    Latif, M A; Schmidt, W; Niemeyer, J C

    2013-01-01T23:59:59.000Z

    Black holes of a billion solar masses are observed in the infant universe a few hundred million years after the Big Bang. The direct collapse of protogalactic gas clouds in primordial halos with $\\rm T_{vir} \\geq 10^{4} K$ provides the most promising way to assemble massive black holes. In this study, we aim to determine the characteristic mass scale of seed black holes and the time evolution of the accretion rates resulting from the direct collapse model. We explore the formation of supermassive black holes via cosmological large eddy simulations (LES) by employing sink particles and following their evolution for twenty thousand years after the formation of the first sink. As the resulting protostars were shown to have cool atmospheres in the presence of strong accretion, we assume here that UV feedback is negligible during this calculation. We confirm this result in a comparison run without sinks. Our findings show that black hole seeds with characteristic mass of $\\rm 10^{5} M_{\\odot}$ are formed in the pr...

  5. Black hole formation in the early universe

    E-Print Network [OSTI]

    Latif, M A; Schmidt, W; Niemeyer, J

    2013-01-01T23:59:59.000Z

    Supermassive black holes with up to a $\\rm 10^{9}~M_{\\odot}$ dwell in the centers of present-day galaxies, and their presence has been confirmed at z $\\geq$ 6. Their formation at such early epochs is still an enigma. Different pathways have been suggested to assemble supermassive black holes in the first billion years after the Big Bang. Direct collapse has emerged as a highly plausible scenario to form black holes as it provides seed masses of $\\rm 10^{5}-10^{6}~M_{\\odot}$. Gravitational collapse in atomic cooling haloes with virial temperatures T$_{vir} \\geq 10^{4}$~K may lead to the formation of massive seed black holes in the presence of an intense background UV flux. Turbulence plays a central role in regulating accretion and transporting angular momentum. We present here the highest resolution cosmological large-eddy simulations to date which track the evolution of high-density regions on scales of $0.25$~AU beyond the formation of the first peak, and study the impact of subgrid-scale turbulence. The pe...

  6. Inflation, Dark Energy, and the Fate of the Universe

    SciTech Connect (OSTI)

    Linde, Andrei (Stanford University) [Stanford University

    2003-11-12T23:59:59.000Z

    Inflationary theory, which describes an accelerated expansion of the early universe, gradually becomes a standard cosmological paradigm. It solves many complicated problems of the usual big bang theory, explains the origin of galaxies, and makes several predictions, which, so far, are in a good agreement with cosmological observations. Recently we learned that few billion years ago the universe entered the second stage of acceleration, driven by mysterious 'dark energy'. According to the simplest version of inflationary theory, the universe is an eternally existing self-reproducing fractal consisting of different balloons of exponentially large size. The universe as a whole can be immortal, but the fate of each of these balloons, including the one in which we live now, depends on the properties of dark energy. According to some of the theories of dark energy, our part of the universe will continue its accelerated expansion forever. Other theories predict that eventually our part of the universe will become ten-dimensional and stop accelerating. Still another possibility is that our part of the universe will collapse. I will describe recent developments in inflationary theory and the theory of dark energy, and discuss the possibility to find our fate by cosmological observations.

  7. Spontaneous symmetry breaking in 2D: Kibble-Zurek mechanism in temperature quenched colloidal monolayers

    E-Print Network [OSTI]

    Patrick Dillmann; Georg Maret; Peter Keim

    2014-09-16T23:59:59.000Z

    The Kibble-Zurek mechanism describes the formation of topological defects during spontaneous symmetry breaking for quite different systems. Shortly after the big bang, the isotropy of the Higgs-field is broken during the expansion and cooling of the universe. Kibble proposed the formation of monopoles, strings, and membranes in the Higgs field since the phase of the symmetry broken field can not switch globally to gain the same value everywhere in space. Zurek pointed out that the same mechanism is relevant for second order phase transitions in condensed matter systems. Every finite cooling rate induces the system to fall out of equilibrium which is due to the critical slowing down of order parameter fluctuations: the correlation time diverges and the symmetry of the system can not change globally but incorporates defects between different domains. Depending on the cooling rate the heterogeneous order parameter pattern are a fingerprint of critical fluctuations. In the present manuscript we show that a monolayer of superparamagnetic colloidal particles is ideally suited to investigate such phenomena. In thermal equilibrium the system undergos continuous phase transitions according KTHNY-theory. If cooled rapidly across the melting temperature the final state is a polycrystal. We show, that the observations can not be explained with nucleation of a supercooled fluid but is compatible with the Kibble-Zurek mechanism.

  8. TASI Lectures on Holographic Space-Time, SUSY and Gravitational Effective Field Theory

    E-Print Network [OSTI]

    Tom Banks

    2010-09-23T23:59:59.000Z

    I argue that the conventional field theoretic notion of vacuum state is not valid in quantum gravity. The arguments use gravitational effective field theory, as well as results from string theory, particularly the AdS/CFT correspondence. Different solutions of the same low energy gravitational field equations correspond to different quantum systems, rather than different states in the same system. I then introduce {\\it holographic space-time} a quasi-local quantum mechanical construction based on the holographic principle. I argue that models of quantum gravity in asymptotically flat space-time will be exactly super-Poincare invariant, because the natural variables of holographic space-time for such a system, are the degrees of freedom of massless superparticles. The formalism leads to a non-singular quantum Big Bang cosmology, in which the asymptotic future is required to be a de Sitter space, with cosmological constant (c.c.) determined by cosmological initial conditions. It is also approximately SUSic in the future, with the gravitino mass $K \\Lambda^{1/4}$.

  9. Part I STATISTICAL PHYSICS 1 Statistical Physics

    E-Print Network [OSTI]

    unknown authors

    In this first part of the book we shall study aspects of classical statistical physics that every physicist should know, but are not usually treated in elementary thermodynamics courses. Our study will lay the microphysical (particle-scale) foundations for the continuum physics of Parts II—VI. As a central feature of our approach, we shall emphasize the intimate connections between the relativistic formulation of statistical physics and its nonrelativistic limit, and between quantum statistical physics and the classical theory. Throughout, we shall presume that the reader is familiar with elementary thermodynamics, but not with other aspects of statistical physics. In Chap. 2 we will study kinetic theory — the simplest of all formalisms for analyzing systems of huge numbers of particles (e.g., molecules of air, or neutrons diffusing through a nuclear reactor, or photons produced in the big-bang origin of the Universe). In kinetic theory the key concept is the “distribution function ” or “number density of particles in phase space”, N; i.e., the number of particles per unit 3-dimensional volume of ordinary space and per unit 3-dimensional volume of momentum space. Despite first appearances, N turns out to be a geometric, frame-independent entity. This N and the frame-independent laws it

  10. Part I STATISTICAL PHYSICS 1 Statistical Physics

    E-Print Network [OSTI]

    unknown authors

    2004-01-01T23:59:59.000Z

    In this first part of the book we shall study aspects of classical statistical physics that every physicist should know, but are not usually treated in elementary thermodynamics courses. Our study will lay the microphysical (particle-scale) foundations for the continuum physics of Parts II—VI. As a central feature of our approach, we shall emphasize the intimate connections between the relativistic formulation of statistical physics and its nonrelativistic limit, and between quantum statistical physics and the classical theory. Throughout, we shall presume that the reader is familiar with elementary thermodynamics, but not with other aspects of statistical physics. In Chap. 2 we will study kinetic theory — the simplest of all formalisms for analyzing systems of huge numbers of particles (e.g., molecules of air, or neutrons diffusing through a nuclear reactor, or photons produced in the big-bang origin of the Universe). In kinetic theory the key concept is the “distribution function ” or “number density of particles in phase space”, N; i.e., the number of particles per unit 3-dimensional volume of ordinary space and per unit 3-dimensional volume of momentum space. Despite first appearances, N turns out to be a geometric, frame-independent entity. This N and the frame-independent laws it

  11. Part I STATISTICAL PHYSICS 1 Statistical Physics

    E-Print Network [OSTI]

    unknown authors

    In this first part of the book we shall study aspects of classical statistical physics that every physicist should know but are not usually treated in elementary thermodynamics courses. This study will lay the microphysical (particle-scale) foundations for the continuum physics of Parts II—VI. Throughout, we shall presume that the reader is familiar with elementary thermodynamics, but not with other aspects of statistical physics. As a central feature of our approach, we shall emphasize the intimate connections between the relativistic formulation of statistical physics and its nonrelativistic limit, and between quantum statistical physics and the classical theory. Chapter 2 will deal with kinetic theory, which is the simplest of all formalisms for studying systems of huge numbers of particles (e.g., molecules of air, or neutrons diffusing through a nuclear reactor, or photons produced in the big-bang origin of the Universe). In kinetic theory the key concept is the “distribution function ” or “number density of particles in phase space”, N; i.e., the number of particles per unit 3-dimensional volume of ordinary space and per unit 3-dimensional volume of momentum space. Despite first appearances, N turns out to be a geometric, frame-independent entity. This N and the laws it obeys provide

  12. Bright X-ray flares in XRF 050406 and GRB 050502B provide evidence for extended central engine activity

    E-Print Network [OSTI]

    Burrows, D N; Falcone, A; Kobayashi, S; Zhang, B; Moretti, A; O'Brien, P T; Goad, M R; Campana, S; Page, K L; Angelini, L; Barthelmy, S D; Beardmore, A P; Capalbi, M; Chincarini, G; Cummings, J; Cusumano, G; Fox, D; Giommi, P; Hill, J E; Kennea, J A; Krimm, H; Mangano, V; Marshall, F; Mészáros, P; Morris, D C; Nousek, J A; Osborne, J P; Pagani, C; Perri, M; Tagliaferri, G; Wells, A A; Woosley, S; Gehrels, N

    2005-01-01T23:59:59.000Z

    Gamma-ray bursts (GRBs) are the most powerful explosions since the Big Bang, with typical energies around 10**51 ergs. Long GRBs (duration > 2 s) are thought to signal the creation of black holes, most likely by collapse of massive stars. The detected signals from the resulting highly relativistic fireball consist of prompt gamma-ray emission (from internal shocks in the fireball) lasting for several seconds to minutes, followed by afterglow emission (from external shocks as the fireball encounters surrounding material) covering a broad range of frequencies from radio through X-rays. Because of the time needed to determine the GRB position, most afterglow measurements have been made hours after the burst, and little is known about the characteristics of afterglows in the minutes following a burst, when the afterglow emission is actively responding to inhomogeneities in both the fireball and the circumburst environment. Here we report our discovery of two bright X-ray flares peaking a few minutes after the bur...

  13. High Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z~6 QSOs

    E-Print Network [OSTI]

    Simcoe, R A

    2006-01-01T23:59:59.000Z

    New measurements of the z~6 intergalactic CIV abundance are presented, using moderate resolution IR spectra of two QSOs taken with GNIRS on Gemini South. These data were systematically searched for high redshift CIV absorption lines, using objective selection criteria. Comprehensive tests were performed to quantify sample incompleteness, as well as the rate of false positive CIV identifications. The trend of constant $\\Omega_{CIV}(z)$ observed at z~2-5 appears to continue to z~6, the highest observed redshift. The CIV sample is also consistent with the redshift-invariant form of the CIV column density distribution reported by Songaila (2001) at lower redshift, although with fairly large uncertainties due to a smaller sample size and noisier infrared data. The constant value of $\\Omega_{CIV}$ does not necessarily imply that the IGM was infused with an early metallicity ``floor,'' but the presence of early CIV does indicate that heavy-element enrichment began < 1 Gyr after the Big Bang. The lack of a decline...

  14. Neutrino Physics from the Cosmic Microwave Background and Large Scale Structure

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Slosar, A.; Arnold, K.; Austermann, J.; Benson, B. A.; Bischoff, C.; Bock, J.; Bond, J. R.; Borrill, J.; Calabrese, E.; Carlstrom, J. E.; et al

    2015-03-01T23:59:59.000Z

    This is a report on the status and prospects of the quantification of neutrino properties through the cosmological neutrino background for the Cosmic Frontier of the Division of Particles and Fields Community Summer Study long-term planning exercise. Experiments planned and underway are prepared to study the cosmological neutrino background in detail via its influence on distance-redshift relations and the growth of structure. The program for the next decade described in this document, including upcoming spectroscopic galaxy surveys eBOSS and DESI and a new Stage-IV CMB polarization experiment CMB-S4, will achieve ? (?mv) = 16 meV and ? (Neff)(Neff) = 0.020.more »Such a mass measurement will produce a high significance detection of non-zero ?m??m?, whose lower bound derived from atmospheric and solar neutrino oscillation data is about 58 meV. If neutrinos have a minimal normal mass hierarchy, this measurement will definitively rule out the inverted neutrino mass hierarchy, shedding light on one of the most puzzling aspects of the Standard Model of particle physics — the origin of mass. This precise a measurement of Neff will allow for high sensitivity to any light and dark degrees of freedom produced in the big bang and a precision test of the standard cosmological model prediction that Neff = 3.046.« less

  15. The Shape and Flow of Heavy Ion Collisions (490th Brookhaven Lecture)

    SciTech Connect (OSTI)

    Schenke, Bjoern [BNL Physics Department

    2014-12-18T23:59:59.000Z

    The sun can’t do it, but colossal machines like the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab and Large Hadron Collider (LHC) in Europe sure can. Quarks and gluons make up protons and neutrons found in the nucleus of every atom in the universe. At heavy ion colliders like RHIC and the LHC, scientists can create matter more than 100,000 times hotter than the center of the sun—so hot that protons and neutrons melt into a plasma of quarks and gluons. The particle collisions and emerging quark-gluon plasma hold keys to understanding how these fundamental particles interact with each other, which helps explain how everything is held together—from atomic nuclei to human beings to the biggest stars—how all matter has mass, and what the universe looked like microseconds after the Big Bang. Dr. Schenke discusses theory that details the shape and structure of heavy ion collisions. He will also explain how this theory and data from experiments at RHIC and the LHC are being used to determine properties of the quark-gluon plasma.

  16. The type Ia supernovae and the Hubble's constant

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2004-07-20T23:59:59.000Z

    The Hubble's constant is usually surmised to be a constant; but the experiments show a large spread and conflicting estimates. According to the plasma-redshift theory, the Hubble's constant varies with the plasma densities along the line of sight. It varies then slightly with the direction and the distance to a supernova and a galaxy. The relation between the magnitudes of type Ia supernovae and their observed redshifts results in an Hubble's constant with an average value in intergalactic space of 59.44 km per s per Mpc. The standard deviation from this average value is only 0.6 km per s per Mpc, but the standard deviation in a single measurement is about 8.2 km per s per Mpc. These deviations do not include possible absolute calibration errors. The experiments show that the Hubble's constant varies with the intrinsic redshifts of the Milky Way galaxy and the host galaxies for type Ia supernovae, and that it varies with the galactic latitude. These findings support the plasma-redshift theory and contradict the contemporary big-bang theory. Together with the previously reported absence of time dilation in type Ia supernovae measurements, these findings have profound consequences for the standard cosmological theory.

  17. Is Hubble's Expansion due to Dark Energy

    E-Print Network [OSTI]

    R. C. Gupta; Anirudh Pradhan

    2010-10-19T23:59:59.000Z

    {\\it The universe is expanding} is known (through Galaxy observations) since 1929 through Hubble's discovery ($V = H D$). Recently in 1999, it is found (through Supernovae observations) that the universe is not simply expanding but is accelerating too. We, however, hardly know only $4\\%$ of the universe. The Wilkinson Microwave Anisotropy Probe (WMAP) satellite observational data suggest $73\\%$ content of the universe in the form of dark-energy, $23\\%$ in the form of non-baryonic dark-matter and the rest $4\\%$ in the form of the usual baryonic matter. The acceleration of the universe is ascribed to this dark-energy with bizarre properties (repulsive-gravity). The question is that whether Hubble's expansion is just due to the shock of big-bang & inflation or it is due to the repulsive-gravity of dark-energy? Now, it is believed to be due to dark-energy, say, by re-introducing the once-discarded cosmological-constant $\\Lambda$. In the present paper, it is shown that `the formula for acceleration due to dark-energy' is (almost) exactly of same-form as `the acceleration formula from the Hubble's law'. Hence, it is concluded that: yes, `indeed it is the dark-energy responsible for the Hubble's expansion too, in-addition to the current on-going acceleration of the universe'.

  18. Warped Tachyonic Inflation in Type IIB Flux Compactifications and the Open-String Completeness Conjecture

    E-Print Network [OSTI]

    Daniel Cremades; Fernando Quevedo; Aninda Sinha

    2005-11-14T23:59:59.000Z

    We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation. Flux-induced `warping' can provide the small slow-roll parameters needed for successful inflation. Constraints on the parameter space leading to sufficient number of e-folds, exit from inflation, density perturbations and stabilization of the Kahler modulus are investigated. The conditions are difficult to satisfy in Klebanov-Strassler throats but can be satisfied in T^3 fibrations and other generic Calabi-Yau manifolds. This requires large volume and magnetic fluxes on the D-brane. The end of inflation may or may not lead to cosmic strings depending on the original non-BPS configuration. A careful investigation of initial conditions leading to a phenomenologically viable model for inflation is carried out. The initial conditions are chosen on the basis of Sen's open string completeness conjecture. We find time symmetrical bounce solutions without initial singularities for k=1 FRW models which are correlated with an inflationary period. Singular big-bang/big-crunch solutions also exist but do not lead to inflation. There is an intriguing correlation between having an inflationary universe in 4 dimensions and 6 compact dimensions or a big-crunch singularity and decompactification.

  19. Gravity Sources in a Quantum Milne Universe

    E-Print Network [OSTI]

    Chew, Geoffrey F

    2011-01-01T23:59:59.000Z

    A quantum-cosmology-suited sliced Milne spacetime, located inside a 'big-bang' forward lightcone, comprises the interiors of a sequence of 4-dimensional slices whose invariant 'age' width is at Planck scale. The age of any lightcone-interior point is its Minkowski distance from the lightcone vertex, but excluded from the spacetime of a 'quantum Milne universe' (QMU) are 3-dimensional slice-separating, ray-carrying hyperboloids. Each (fixed-age) slice boundary houses a Gelfand-Naimark unitarily Lorentz-transformable cosmological-Fock-space ray-a sum of tensor products of complex normed fiber-bundle 'source' functions. Each bundle is a unit 3-sphere (fiber) over an invariantly metricized 3-hyperboloid (base space). The evolving QMU comprises a slice-interior sequence (each interior a 4-manifold) and a ray sequence housed by the slice-separating 3-manifolds. Throughout each slice interior, the preceding ray specifies classical-field reality. Action, of elsewhere-prescribed slice-traversing Feynman paths, determi...

  20. The Fluid Nature of Quark-Gluon Plasma

    E-Print Network [OSTI]

    W. A. Zajc

    2008-02-25T23:59:59.000Z

    Collisions of heavy nuclei at very high energies offer the exciting possibility of experimentally exploring the phase transformation from hadronic to partonic degrees of freedom which is predicted to occur at several times normal nuclear density and/or for temperatures in excess of $\\sim 170$ MeV. Such a state, often referred to as a quark-gluon plasma, is thought to have been the dominant form of matter in the universe in the first few microseconds after the Big Bang. Data from the first five years of heavy ion collisions of Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) clearly demonstrate that these very high temperatures and densities have been achieved. While there are strong suggestions of the role of quark degrees of freedom in determining the final-state distributions of the produced matter, there is also compelling evidence that the matter does {\\em not} behave as a quasi-ideal state of free quarks and gluons. Rather, its behavior is that of a dense fluid with very low kinematic viscosity exhibiting strong hydrodynamic flow and nearly complete absorption of high momentum probes. The current status of the RHIC experimental studies is presented, with a special emphasis on the fluid properties of the created matter, which may in fact be the most perfect fluid ever studied in the laboratory.

  1. FRW Cosmologies with Adiabatic Matter Creation

    E-Print Network [OSTI]

    J. A. S. Lima; A. S. M. Germano; L. R. W. Abramo

    1995-11-02T23:59:59.000Z

    Some properties of cosmological models with matter creation are investigated in the framework of the Friedman-Robertson-Walker (FRW) line element. For adiabatic matter creation, as developed by Prigogine and coworkers, we derive a simple expression relating the particle number density $n$ and energy density $\\rho$ which holds regardless of the matter creation rate. The conditions to generate inflation are discussed and by considering the natural phenomenological matter creation rate $\\psi =3 \\beta nH$, where $\\beta$ is a pure number of the order of unity and $H$ is the Hubble parameter, a minimally modified hot big-bang model is proposed. The dynamic properties of such models can be deduced from the standard ones simply by replacing the adiabatic index $\\gamma$ of the equation of state by an effective parameter $\\gamma_{*} = \\gamma (1 - \\beta)$. The thermodynamic behavior is determined and it is also shown that ages large enough to agree with observations are obtained even given the high values of $H$ suggested by recent measurements.

  2. The Standard Cosmological Model and CMB Anisotropies

    E-Print Network [OSTI]

    James G. Bartlett

    1999-03-17T23:59:59.000Z

    This is a course on cosmic microwave background (CMB) anisotropies in the standard cosmological model, designed for beginning graduate students and advanced undergraduates. ``Standard cosmological model'' in this context means a Universe dominated by some form of cold dark matter (CDM) with adiabatic perturbations generated at some initial epoch, e.g., Inflation, and left to evolve under gravity alone (which distinguishes it from defect models). The course is primarily theoretical and concerned with the physics of CMB anisotropies in this context and their relation to structure formation. Brief presentations of the uniform Big Bang model and of the observed large--scale structure of the Universe are given. The bulk of the course then focuses on the evolution of small perturbations to the uniform model and on the generation of temperature anisotropies in the CMB. The theoretical development is performed in the (pseudo--)Newtonian gauge because it aids intuitive understanding by providing a quick reference to classical (Newtonian) concepts. The fundamental goal of the course is not to arrive at a highly exact nor exhaustive calculation of the anisotropies, but rather to a good understanding of the basic physics that goes into such calculations.

  3. Synthesis of ethylene-propylene rubber graft copolymers by borane approach

    SciTech Connect (OSTI)

    Chung, T.C.; Janvikul, W.; Bernard, R.; Jiang, G.J. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering)

    1994-01-01T23:59:59.000Z

    This paper describes a new method to prepare graft copolymers which have an EP rubber backbone and several free radical polymerized polymers grafted thereto. The process involves hydroboration of commercial EPDM rubbers, such as poly(ethylene-co-propylene-co-1,4-hexadiene) and poly(ethylene-co-propylene-co-5-ethylidene-2-norbornene), with 9-borabicyclononane (9-BBN). The resulting secondary alkyl-9-BBN moieties in the EPDM copolymer were then exposed to oxygen in the presence of free radical polymerizable monomers. Under certain conditions, the selective autoxidation reaction of secondary alkyl-9-BBN took place to create desirable polymeric radicals which can in situ initiate free radical polymerization. High graft efficiency was observed with controllable copolymer compositions. The graft copolymer of EP-g-PMMA is used to show the chemistry as well as some of the physical properties.

  4. Electronic effects in the Diels-Alder reactions of vinylboranes

    E-Print Network [OSTI]

    Watson, Jose Vernon

    1992-01-01T23:59:59.000Z

    &H NMR spectrum of the oxidized products in the competitive reaction of 4a and 4b with vinyl-9-BBN 10 tH NMR spectrum of the oxidized products in the competitive reaction of 4b and 4c with vinyl-9-BBN 11 tH NMR spectrum of trivinylborane. 12 t...~C NMR spectrum of trivinylborane . 13 Plot of the reaction ratio versus time 17 21 22 26 27 in the reaction of 4a with trivinylborane 31 LIST OF FIGURES (Continued) 14 Plot of the reaction ratio versus time in the reaction of cyclopentadiene...

  5. Quantum Kinetics of Neutrinos in Hot, Dense Environments /

    E-Print Network [OSTI]

    Vlasenko, Alexey

    2014-01-01T23:59:59.000Z

    Stars and Core Collapse Supernovae 1.1.3 Compact Objecttransforma- tion in supernovae,” Physical Review D, vol. 74,nucleosynthesis in supernovae,” Physical Review Letters,

  6. ake-02r system neutron: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    or different masses of the binary components. Implications for nucleosynthesis and gamma ray bursts are discussed. Test calculations for the used viscosity scheme are provided in...

  7. asymmetric thermal neutron: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    or different masses of the binary components. Implications for nucleosynthesis and gamma ray bursts are discussed. Test calculations for the used viscosity scheme are provided in...

  8. asymmetric central star: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    or different masses of the binary components. Implications for nucleosynthesis and gamma ray bursts are discussed. Test calculations for the used viscosity scheme are provided in...

  9. E-Print Network 3.0 - astrophysics gravitational waves Sample...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    position in astrophysics 3D supercomputer simulation of the formation Summary: , Gamma-ray bursts, nucleosynthesis, sources of gravitational waves and computational methods....

  10. Laser-Compton backscattering for nuclear astrophysics

    SciTech Connect (OSTI)

    Utsunomiya, Hiroaki [Department of Physics, Konan University, 8-9-1, Okamoto, Higashinada, Kobe 658-85-1, Japan and The Center for Nuclear Study, University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

    2014-05-09T23:59:59.000Z

    Using ?-ray beams for experimental nucleosynthesis study forms a new branch of nuclear astrophysics. I introduce typical experimental investigations and give a future prospect of this branch.

  11. alpha gamma reaction: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    nucleosynthesis in baryon inhomogeneous cosmological models. To calculate the thermonuclear reaction rate in a wide range of temperatures, we numerically integrate the...

  12. alpha os reaction: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    nucleosynthesis in baryon inhomogeneous cosmological models. To calculate the thermonuclear reaction rate in a wide range of temperatures, we numerically integrate the...

  13. alpha reactions: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    nucleosynthesis in baryon inhomogeneous cosmological models. To calculate the thermonuclear reaction rate in a wide range of temperatures, we numerically integrate the...

  14. alpha xn reactions: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    nucleosynthesis in baryon inhomogeneous cosmological models. To calculate the thermonuclear reaction rate in a wide range of temperatures, we numerically integrate the...

  15. Supernovae

    E-Print Network [OSTI]

    Trimble, VL

    1981-01-01T23:59:59.000Z

    Young extragalactic supernovae have now been seen as radio,about 2 years, finding supernovae out to the Virgo clusterprobe nucleosynthesis by supernovae. E. Kibblewhite and M.

  16. Neutrinos in physics, astrophysics, and cosmology

    E-Print Network [OSTI]

    A. D. Dolgov

    2000-06-12T23:59:59.000Z

    A brief review of neutrino anomalies in particle physics and of the role played by neutrinos in cosmology and astrophysics is presented. The main part of the talk is dedicated to the impact of neutrinos and in particular of neutrino oscillations on BBN and to a possible spatial variation of primordial abundances.

  17. Decision Support for Choice of Security

    E-Print Network [OSTI]

    Langseth, Helge

    Decision Support for Choice of Security Solution The Aspect-Oriented Risk Driven Development (AORDD decisions. (4) RDD annotation rules for security risk and security solution variable estimation. (5) The AORDD security solution trade-o¤ analysis and trade-o¤ tool BBN topology. (6) Rule set for how

  18. 1 Antenna Beamforming and Power Control for Ad Hoc Networks

    E-Print Network [OSTI]

    Ramanathan, Ram

    1 Antenna Beamforming and Power Control for Ad Hoc Networks RAM RAMANATHAN BBN Technologies power, spreading code, and antenna beams. By controlling these transceiver parameters adaptively, coding, etc.) can also yield benefits, we shall focus on antenna and power control as they have been

  19. COSMOLOGICAL LITHIUM PROBLEM: A DIFFERENT APPROACH

    E-Print Network [OSTI]

    ?umer, Slobodan

    LITHIUM 7Li sources BBN cosmic-ray interactions (ingredients: shock waves, magnetic field, chargedCOSMOLOGICAL LITHIUM PROBLEM: A DIFFERENT APPROACH Tijana Prodanovi, University of Novi Sad Tamara Observations - boxes 4He ­ OK D ­ right on! 7Li ­ problem! Factor of 3-4 discrepancy! LITHIUM PROBLEM

  20. Efficient Clustering Algorithms for Self-Organizing Wireless Sensor Networks

    E-Print Network [OSTI]

    Starobinski, David

    Efficient Clustering Algorithms for Self-Organizing Wireless Sensor Networks Rajesh Krishnan BBN@bu.edu Abstract Self-organization of wireless sensor networks, which involves network decomposi- tion-organization in wireless sensor networks. We first present a novel approach for message-efficient clustering, in which

  1. A Bayesian Belief Network of Threat Anticipation and Terrorist Motivations

    SciTech Connect (OSTI)

    Olama, Mohammed M [ORNL; Allgood, Glenn O [ORNL; Davenport, Kristen M [ORNL; Schryver, Jack C [ORNL

    2010-01-01T23:59:59.000Z

    Recent events highlight the need for efficient tools for anticipating the threat posed by terrorists, whether individual or groups. Antiterrorism includes fostering awareness of potential threats, deterring aggressors, developing security measures, planning for future events, halting an event in process, and ultimately mitigating and managing the consequences of an event. To analyze such components, one must understand various aspects of threat elements like physical assets and their economic and social impacts. To this aim, we developed a three-layer Bayesian belief network (BBN) model that takes into consideration the relative threat of an attack against a particular asset (physical layer) as well as the individual psychology and motivations that would induce a person to either act alone or join a terrorist group and commit terrorist acts (social and economic layers). After researching the many possible motivations to become a terrorist, the main factors are compiled and sorted into categories such as initial and personal indicators, exclusion factors, and predictive behaviors. Assessing such threats requires combining information from disparate data sources most of which involve uncertainties. BBN combines these data in a coherent, analytically defensible, and understandable manner. The developed BBN model takes into consideration the likelihood and consequence of a threat in order to draw inferences about the risk of a terrorist attack so that mitigation efforts can be optimally deployed. The model is constructed using a network engineering process that treats the probability distributions of all the BBN nodes within the broader context of the system development process.

  2. Neutrinos, Rare Isotopes of Exotic Nuclei and Nuclear Astrophysics

    E-Print Network [OSTI]

    A. B. Balantekin

    2014-10-21T23:59:59.000Z

    The connection between neutrino physics, nucleosynthesis of elements in astrophysical sites, laboratory measurements with rare exotic nuclei and astronomical observations is discussed. The key role played by neutrinos is emphasized and the close connection between neutrino physics and nucleosynthesis is highlighted.

  3. THE AsntDPHYSiCAL : 294-2^7, 1986 April 1

    E-Print Network [OSTI]

    Shlyakhter, Ilya

    into 22 Nc). Then neutrons are slowed down mainly due to their scattering on 4 Hc (f = Or425, . ENHANCEMENT OF NUCLEOSYNTHESIS REACTION RATES DUE TO NONTHERMALIZED FAST NEUTRONS Yu, V. PETROV AND A. I It is usually assumed in stellar nucleosynthesis calculations that neutrons art completely thcrmalizcd. Hence

  4. Inflation, quintessence, and the origin of mass

    E-Print Network [OSTI]

    C. Wetterich

    2014-12-12T23:59:59.000Z

    In a unified picture both inflation and present dynamical dark energy arise from the same scalar field. The history of the Universe describes a crossover from a scale invariant "past fixed point" where all particles are massless, to a "future fixed point" for which spontaneous breaking of the exact scale symmetry generates the particle masses. The cosmological solution can be extrapolated to the infinite past in physical time - the universe has no beginning. This is seen most easily in a frame where particle masses and the Planck mass are field-dependent and increase with time. In this "freeze frame" the Universe shrinks and heats up during radiation and matter domination. In the equivalent, but singular Einstein frame cosmic history finds the familiar big bang description. The vicinity of the past fixed point corresponds to inflation. It ends at a first stage of the crossover. For the primordial fluctuations we find a spectral index $n\\lesssim 0.967$ and a tensor amplitude $r\\gtrsim 0.13$, with typical values close to the bounds. The crossover is completed by a second stage where the beyond-standard-model sector undergoes the transition to the future fixed point. The resulting increase of neutrino masses stops a cosmological scaling solution, relating the present dark energy density to the present neutrino mass. A simple model with no more free parameters than $\\Lambda$CDM is compatible with all present observational tests. We discuss how the fixed points are rooted within quantum gravity in a crossover between ultraviolet and infrared fixed points. Thus quantum properties of gravity can be tested both by very early and late cosmology.

  5. Quintom Cosmology: Theoretical implications and observations

    E-Print Network [OSTI]

    Yi-Fu Cai; Emmanuel N. Saridakis; Mohammad R. Setare; Jun-Qing Xia

    2010-04-22T23:59:59.000Z

    We review the paradigm of quintom cosmology. This scenario is motivated by the observational indications that the equation of state of dark energy across the cosmological constant boundary is mildly favored, although the data are still far from being conclusive. As a theoretical setup we introduce a no-go theorem existing in quintom cosmology, and based on it we discuss the conditions for the equation of state of dark energy realizing the quintom scenario. The simplest quintom model can be achieved by introducing two scalar fields with one being quintessence and the other phantom. Based on the double-field quintom model we perform a detailed analysis of dark energy perturbations and we discuss their effects on current observations. This type of scenarios usually suffer from a manifest problem due to the existence of a ghost degree of freedom, and thus we review various alternative realizations of the quintom paradigm. The developments in particle physics and string theory provide potential clues indicating that a quintom scenario may be obtained from scalar systems with higher derivative terms, as well as from non-scalar systems. Additionally, we construct a quintom realization in the framework of braneworld cosmology, where the cosmic acceleration and the phantom divide crossing result from the combined effects of the field evolution on the brane and the competition between four and five dimensional gravity. Finally, we study the outsets and fates of a universe in quintom cosmology. In a scenario with null energy condition violation one may obtain a bouncing solution at early times and therefore avoid the Big Bang singularity. Furthermore, if this occurs periodically, we obtain a realization of an oscillating universe. Lastly, we comment on several open issues in quintom cosmology and their connection to future investigations.

  6. Beryllium in Ultra-Lithium-Deficient Halo Stars - The Blue Straggler Connection

    E-Print Network [OSTI]

    Ann Merchant Boesgaard

    2007-05-10T23:59:59.000Z

    There are nine metal-deficient stars that have Li abundances well below the Li plateau that is defined by over 100 unevolved stars with temperatures above 5800 K and values of [Fe/H] $<$ $-$1.0. Abundances of Be have been determined for most of these ultra-Li-deficient stars in order to investigate the cause of the Li deficiencies. High-resolution and high signal-to-noise spectra have been obtained in the Be II spectral region near 3130 \\AA for six ultra-Li-deficient stars with the Keck I telescope and its new uv-sensitive CCD on the upgraded HIRES. The spectrum synthesis technique has been used to determine Be abundances. All six stars are found to have Be deficiencies also. Two have measurable - but reduced - Be and four have only upper limits on Be. These results are consistent with the idea that these Li- and Be-deficient stars are analogous to blue stragglers. The stars have undergone mass transfer events (or mergers) which destroy or dilute both Li and Be. The findings cannot be matched by the models that predict that the deficiencies are due to extra-mixing in a subset of halo stars that were initially rapid rotators, with the possible exception of one star, G 139-8. Because the ultra-Li-deficient stars are also Be-deficient, they appear to be genuine outliers in population of halo stars used to determine the value of primordial Li; they no longer have the Li in their atmospheres that was produced in the Big Bang.

  7. Hydro-Gravitational-Dynamics of Planets and Dark Energy

    E-Print Network [OSTI]

    Carl H. Gibson; Rudolph E. Schild

    2008-08-24T23:59:59.000Z

    Self-gravitational fluid mechanical methods termed hydro-gravitational-dynamics (HGD) predict plasma fragmentation 0.03 Myr after the turbulent big bang to form protosuperclustervoids, turbulent protosuperclusters, and protogalaxies at the 0.3 Myr transition from plasma to gas. Linear protogalaxyclusters fragment at 0.003 Mpc viscous-inertial scales along turbulent vortex lines or in spirals, as observed. The plasma protogalaxies fragment on transition into white-hot planet-mass gas clouds (PFPs) in million-solar-mass clumps (PGCs) that become globular-star-clusters (GCs) from tidal forces or dark matter (PGCs) by freezing and diffusion into 0.3 Mpc halos with 97% of the galaxy mass. The weakly collisional non-baryonic dark matter diffuses to > Mpc scales and frag-ments to form galaxy cluster halos. Stars and larger planets form by binary mergers of the trillion PFPs per PGC on 0.03 Mpc galaxy accretion disks. Star deaths depend on rates of planet accretion and internal star mixing. Moderate accretion rates produce white dwarfs that evaporate surrounding gas planets by spin-radiation to form planetary nebulae before Supernova Ia events, dimming some events to give systematic distance errors misinterpreted as the dark energy hypothesis and overestimates of the universe age. Failures of standard LCDM cosmological models reflect not only obsolete Jeans 1902 fluid mechanical assumptions, but also failures of standard turbulence models that claim the cascade of turbulent kinetic energy is from large scales to small. Because turbulence is always driven at all scales by inertial-vortex forces the turbulence cascade is always from small scales to large.

  8. New variables for the Lemaître-Tolman-Bondi dust solutions

    E-Print Network [OSTI]

    Roberto A. Sussman; Luis García Trujillo

    2001-05-23T23:59:59.000Z

    We re-examine the Lem\\^aitre-Tolman-Bondi (LTB) solutions with a dust source admitting symmetry centers. We consider as free parameters of the solutions the initial value functions: $Y_i$, $\\rho_i$ and $\\Ri$, obtained by restricting the curvature radius, $Y\\equiv \\sqrt{g_{\\theta\\theta}}$, the rest mass density, $\\rho$, and the 3-dimensional Ricci scalar of the rest frames, $\\R$, to an arbitrary regular Cauchy hypersurface, $\\Ti$, marked by constant cosmic time ($t=t_i$). Using $Y_i$ to fix the radial coordinate and the topology (homeomorphic class) of $\\Ti$, and scaling the time evolution in terms of an adimensional scale factor $y=Y/Y_i$, we show that the dynamics, regularity conditions and geometric features of the models are determined by $\\rho_i$, $\\Ri$ and by suitably constructed volume averages and contrast functions expressible in terms of invariant scalars defined in $\\Ti$. These quantities lead to a straightforward characterization of initial conditions in terms of the nature of the inhomogeneity of $\\Ti$, as density and/or curvature overdensities (``lumps'') and underdensities (''voids'') around a symmetry center. In general, only models with initial density and curvature lumps evolve without shell crossing singularities, though special classes of initial conditions, associated with a simmultaneous big bang, allow for a regular evolution for initial density and curvature voids. Specific restrictions are found so that a regular evolution for $t>t_i$ is possible for initial voids. A step-by-step guideline is provided for using the new variables in the construction of LTB models and for plotting all relevant quantities.

  9. Hotter, Denser, Faster, Smaller...and Nearly Perfect: What's the Matter at RHIC? (410th Brookhaven Lecture)

    SciTech Connect (OSTI)

    Steinberg, Peter (Chemistry Dept) [Chemistry Dept

    2005-12-21T23:59:59.000Z

    The collisions of two beams of heavy-ion particles, atoms stripped of their electrons, speeding around BNL’s immense Relativistic Heavy Ion Collider (RHIC) have long been expected to create a “quark-gluon plasma” in which the quarks and gluons that make up the protons and neutrons in the ions would move freely in a plasma-like system. But the final particles, detectable in the four experiments placed around the RHIC ring, tend to hide information about the earlier, hotter stage. So it is a challenge to elucidate the nature of the primordial system. What surprised scientists, however, was how strongly the quarks and gluons seemed to interact during the collision. This strong interaction makes the system produced at RHIC behave almost like a perfect fluid, one in which the hot matter formed shows a high degree of collectivity among the particles, rather than a gas, in which individual molecules move about randomly. Evidence from the four RHIC detectors has shown that the system formed at RHIC is potentially the most perfect fluid found in nature, at least since a few microseconds after the Big Bang, a state which RHIC was built to re-create. This result is all the more amazing since the system is so small, the collisions forming over distances 100 times smaller than a proton, and forms so quickly, in times on the order of a millionth of a billionth of a billionth of a second (10-24 seconds). It was even interesting enough to the wider physics community to warrant first place in the American Institute of Physics’ year-end review of top physics stories.

  10. Intensity-Frontier Antiproton Physics with The Antiproton Annihilation Spectrometer (TAPAS) at Fermilab

    SciTech Connect (OSTI)

    Apollinari, Giorgio; /Fermilab; Asner, David M.; /PNL, Richland; Baldini, Wander; /INFN, Ferrara; Bartoszek, Larry; Broemmelsiek, Daniel R.; Brown, Charles N.; /Fermilab; Chakravorty, Alak; /St. Xavier U., Chicago; Colas, Paul; /Saclay; Derwent, Paul; /Fermilab; Drutskoy, Alexey; /Moscow, ITEP; Fortner, Michael; /Northern Illinois U. /Saclay /Indian Inst. Tech., Hyderabad

    2011-11-01T23:59:59.000Z

    The Fermilab Antiproton Source is the world's most intense source of antimatter. With the Tevatron program now behind us, this unique facility can help make the case for Fermilab's continued accelerator operations. The Antiproton Source can be used for unique, dedicated antimatter studies, including medium-energy {bar p}-annihilation experiments. We propose to assemble a powerful, yet cost-effective, solenoidal magnetic spectrometer for antiproton-annihilation events, and to use it at the Fermilab Antiproton Accumulator to measure the charm production cross section, study rare hyperon decays, search for hyperon CP asymmetry, precisely measure the properties of several charmonium and nearby states, and make the first measurements of the Drell-Yan continuum in medium-energy antiproton annihilation. Should the charm production cross section be as large as some have proposed, we will also be able to measure D{sup 0}-{bar D}{sup 0} mixing with high precision and discover (or sensitively limit) charm CP violation. The observation of charm or hyperon CP violation would be evidence for physics beyond the Standard Model, with possible implications for the origin of the baryon asymmetry of the universe - the question of what happened to all the antimatter that must have been produced in the Big Bang. The experiment will be carried out by an international collaboration and will require some four years of running time. As possibly the sole hadron experiment in progress at Fermilab during that time, it will play an important role in maintaining a broad particle physics program at Fermilab and in the U.S. It will thus help us to continue attracting creative and capable young people into science and technology, and introducing them to the important technologies of accelerators, detectors, and data acquisition and analysis - key roles in society that accelerator-based particle physics has historically played.

  11. The premature formation of high-redshift galaxies

    SciTech Connect (OSTI)

    Melia, Fulvio, E-mail: fmelia@email.arizona.edu [Department of Physics, The Applied Math Program, and Steward Observatory, The University of Arizona, Tucson AZ 85721 (United States)

    2014-05-01T23:59:59.000Z

    Observations with WFC3/IR on the Hubble Space Telescope and the use of gravitational lensing techniques have facilitated the discovery of galaxies as far back as z ? 10-12, a truly remarkable achievement. However, this rapid emergence of high-z galaxies, barely ?200 Myr after the transition from Population III star formation to Population II, appears to be in conflict with the standard view of how the early universe evolved. This problem has much in common with the better known (and probably related) premature appearance of supermassive black holes at z ? 6. It is difficult to understand how ?10{sup 9} M {sub ?} black holes could have appeared so quickly after the big bang without invoking non-standard accretion physics and the formation of massive seeds, neither of which is seen in the local universe. In earlier work, we showed that the appearance of high-z quasars could instead be understood more reasonably in the context of the R {sub h} = ct universe, which does not suffer from the same time compression issues as ?CDM does at early epochs. Here, we build on that work by demonstrating that the evolutionary growth of primordial galaxies was consistent with the current view of how the first stars formed, but only with the timeline afforded by the R {sub h} = ct cosmology. We also show that the growth of high-z quasars was mutually consistent with that of the earliest galaxies, though it is not yet clear whether the former grew from 5-20 M {sub ?} seeds created in Population III or Population II supernova explosions.

  12. The advanced computational testing and simulation toolkit (ACTS)

    SciTech Connect (OSTI)

    Drummond, L.A.; Marques, O.

    2002-05-21T23:59:59.000Z

    During the past decades there has been a continuous growth in the number of physical and societal problems that have been successfully studied and solved by means of computational modeling and simulation. Distinctively, a number of these are important scientific problems ranging in scale from the atomic to the cosmic. For example, ionization is a phenomenon as ubiquitous in modern society as the glow of fluorescent lights and the etching on silicon computer chips; but it was not until 1999 that researchers finally achieved a complete numerical solution to the simplest example of ionization, the collision of a hydrogen atom with an electron. On the opposite scale, cosmologists have long wondered whether the expansion of the Universe, which began with the Big Bang, would ever reverse itself, ending the Universe in a Big Crunch. In 2000, analysis of new measurements of the cosmic microwave background radiation showed that the geometry of the Universe is flat, and thus the Universe will continue expanding forever. Both of these discoveries depended on high performance computer simulations that utilized computational tools included in the Advanced Computational Testing and Simulation (ACTS) Toolkit. The ACTS Toolkit is an umbrella project that brought together a number of general purpose computational tool development projects funded and supported by the U.S. Department of Energy (DOE). These tools, which have been developed independently, mainly at DOE laboratories, make it easier for scientific code developers to write high performance applications for parallel computers. They tackle a number of computational issues that are common to a large number of scientific applications, mainly implementation of numerical algorithms, and support for code development, execution and optimization. The ACTS Toolkit Project enables the use of these tools by a much wider community of computational scientists, and promotes code portability, reusability, reduction of duplicate efforts, and tool maturity. This paper presents a brief introduction to the functionality available in ACTS.

  13. Redshift of photons penetrating a hot plasma

    E-Print Network [OSTI]

    Ari Brynjolfsson

    2005-10-07T23:59:59.000Z

    A new interaction, plasma redshift, is derived, which is important only when photons penetrate a hot, sparse electron plasma. The derivation of plasma redshift is based entirely on conventional axioms of physics. When photons penetrate a cold and dense plasma, they lose energy through ionization and excitation, Compton scattering on the individual electrons, and Raman scattering on the plasma frequency. But in sparse hot plasma, such as in the solar corona, the photons lose energy also in plasma redshift. The energy loss per electron in the plasma redshift is about equal to the product of the photon's energy and one half of the Compton cross-section per electron. In quiescent solar corona, this heating starts in the transition zone to the corona and is a major fraction of the coronal heating. Plasma redshift contributes also to the heating of the interstellar plasma, the galactic corona, and the intergalactic plasma. Plasma redshift explains the solar redshifts, the redshifts of the galactic corona, the cosmological redshifts, the cosmic microwave background, and the X-ray background. The plasma redshift explains the observed magnitude-redshift relation for supernovae SNe Ia without the big bang, dark matter, or dark energy. There is no cosmic time dilation. The universe is not expanding. The plasma redshift, when compared with experiments, shows that the photons' classical gravitational redshifts are reversed as the photons move from the Sun to the Earth. This is a quantum mechanical effect. As seen from the Earth, a repulsion force acts on the photons. This means that there is no need for Einstein's Lambda term. The universe is quasi-static, infinite, and everlasting.

  14. Institutional plan. FY 1998--2003

    SciTech Connect (OSTI)

    NONE

    1997-07-01T23:59:59.000Z

    This Institutional Plan for Argonne National Laboratory contains central elements of Argonne`s strategic plan. Chapter II of this document discusses the Laboratory`s mission and core competencies. Chapter III presents the Science and Technology Strategic Plan, which summarizes key features of the external environment, presents Argonne`s vision, and describes how the Laboratory`s strategic goals and objectives map onto and support DOE`s four business lines. The balance of the chapter comprises the science and technology area plans, organized by the four DOE business lines. Chapter IV describes the Laboratory`s ten major initiatives, which cover a broad spectrum of science and technology. Our proposal for an Exotic Beam Facility aims at, among other things, increased understanding of the processes of nuclear synthesis during and shortly after the Big Bang. Our Advanced Transportation Technology initiative involves working with US industry to develop cost-effective technologies to improve the fuel efficiency and reduce the emissions of transportation systems. The Laboratory`s plans for the future depend significantly on the success of its major initiatives. Chapter V presents our Operations and Infrastructure Strategic Plan. The main body of the chapter comprises strategic plans for human resources; environmental protection, safety, and health; site and facilities; and information management. The chapter concludes with a discussion of the business and management practices that Argonne is adopting to improve the quality and cost-effectiveness of its operations. The structure and content of this document depart from those of the Institutional Plan in previous years. Emphasis here is on directions for the future; coverage of ongoing activities is less detailed. We hope that this streamlined plan is more direct and accessible.

  15. New Hubble Space Telescope Observations of Heavy Elements in Four Metal-Poor Stars

    E-Print Network [OSTI]

    Roederer, Ian U.

    Elements heavier than the iron group are found in nearly all halo stars. A substantial number of these elements, key to understanding neutron-capture nucleosynthesis mechanisms, can only be detected in the near-ultraviolet. ...

  16. The Pygmy Dipole Resonance status and new experimental developments

    E-Print Network [OSTI]

    Zilges, Andreas

    Dipole Resonance (GDR) Phys. Rev. 71 (1947) 3 1947: Photo-Fission in Uranium #12;Giant Dipole Resonance radius · Slope of symmetry energy in EoS · Impact on nucleosynthesis S. Goriely, PLB 436 (1998) 10 E

  17. The Pygmy Dipole Resonance status and new developments

    E-Print Network [OSTI]

    Zilges, Andreas

    : #12;Giant Dipole Resonance (GDR) Phys. Rev. 71 (1947) 3 1947: Photo-Fission in Uranium #12;Giant to neutron skin, neutron star radius · Slope of symmetry energy in EoS · Impact on nucleosynthesis S. Goriely

  18. Astrophysics With Presolar Stardust Donald D. Clayton1

    E-Print Network [OSTI]

    Nittler, Larry R.

    ................... 10 4.2.1. Silicon and Nitrogen Isotopes ........................... 10 4.2.2. Neutron................................................... 14 5.1.1. AGB nucleosynthesis....................................... 14 5.1.2. Silicon and Titanium

  19. The origins of light and heavy r-process elements identified by chemical tagging of metal-poor stars

    E-Print Network [OSTI]

    Tsujimoto, Takuji

    2014-01-01T23:59:59.000Z

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration gamma-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A>130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process pr...

  20. The First Miniquasar

    E-Print Network [OSTI]

    M. Kuhlen; P. Madau

    2005-08-24T23:59:59.000Z

    We investigate the environmental impact of the first active galactic nuclei that may have formed ~150 Myr after the big bang in low-mass ~10^6 Msun minihaloes. Using Enzo, an adaptive-mesh refinement cosmological hydrodynamics code, we carry out three-dimensional simulations of the radiative feedback from `miniquasars' powered by intermediate-mass black holes. We follow the non-equilibrium multispecies chemistry of primordial gas in the presence of a point source of X-ray radiation, which starts shining in a rare high-sigma peak at z=21 and emits a power-law spectrum in the 0.2-10 keV range. We find that, after one Salpeter time-scale, the miniquasar has heated up the simulation box to a volume-averaged temperature of 2800 K. The mean electron and H2 fractions are now 0.03 and 4e-5: the latter is 20 times larger than the primordial value, and will delay the buildup of a uniform UV photodissociating background. The net effect of the X-rays is to reduce gas clumping in the IGM by as much as a factor of 3. While the suppression of baryonic infall lowers the gas mass fraction at overdensities delta in the range 20-2000, enhanced molecular cooling increases the amount of dense material at delta>2000. In many haloes within the proximity of our miniquasar the H2-boosting effect of X-rays is too weak to overcome heating, and the cold and dense gas mass actually decreases. We find little evidence for an entropy floor in gas at intermediate densities preventing gas contraction and H2 formation. Overall, the radiative feedback from X-rays enhances gas cooling in lower-sigma peaks that are far away from the initial site of star formation, thus decreasing the clustering bias of the early pregalactic population, but does not appear to dramatically reverse or promote the collapse of pregalactic clouds as a whole. (abridged)