Sample records for oxford big-bang nucleosynthesis

  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. 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.

  3. 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.

  4. 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).

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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).

  11. 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.

  12. 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.

  13. 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_{\

  14. 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_{\

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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 \

  8. 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).

  9. 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- " "

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. "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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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 )

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. Technology Transfer from the University of Oxford

    E-Print Network [OSTI]

    Paxton, Anthony T.

    Technology Transfer from the University of Oxford www.isis-innovation.com #12;Isis Innovation Ltd Oxford Technology Transfer IP, Patents, Licences, Spin-outs, Material Sales, Seed Funds, Isis Angels Network Oxford Expertise Consulting, Services Isis Consulting Business Technology Transfer and Innovation

  1. 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.

  2. 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 .......

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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

  9. 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 .......

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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;

  15. 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...

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. BAS C. VAN FRAASSEN CLARENDON PRESS -OXFORD

    E-Print Network [OSTI]

    Fitelson, Branden

    THE SCIENTIFIC IMAGE BAS C. VAN FRAASSEN CLARENDON PRESS - OXFORD #12;18 ARGUMENTS CONCERNING adequate, ones whose models fit the observable phenomena. while recognizing that what counts

  2. Top Tips for Accessing Oxford's Information Resources

    E-Print Network [OSTI]

    Oxford, University of

    Top Tips for Accessing Oxford's Information Resources And How Brasenose College Library Fits In #12, electronic journals and books Top Tip 1: Attend the induction session in your departmental library #12;Oxford ­ departmental, faculty, college Top Tip 2: Explore smaller libraries ­ www

  3. Top Tips for Accessing Oxford's Information Resources

    E-Print Network [OSTI]

    Oxford, University of

    Top Tips for Accessing Oxford's Information Resources And How Brasenose College Library Fits In #12, electronic journals and books Top Tip 1: Attend the Bodleian induction sessions for your subject #12;Oxford ­ departmental, faculty, college Top Tip 2: Explore smaller libraries ­ www

  4. University of Oxford Environmental Sustainability Policy 2008

    E-Print Network [OSTI]

    Melham, Tom

    1 University of Oxford Environmental Sustainability Policy 2008 ENERGY ­ the University of Oxford Energy Policy is to reduce its buildings and process carbon dioxide emissions in line with UK government Policy is to reduce the emission of greenhouse gases (GHGs) deriving from energy consumption and other

  5. 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.

  6. 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 $\

  7. 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 $\

  8. 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.

  9. 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. ...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. OXFORD UNIVERSITY JOINT COMMITTEE FOR MATHEMATICS AND

    E-Print Network [OSTI]

    OXFORD UNIVERSITY JOINT COMMITTEE FOR MATHEMATICS AND PHILOSOPHY October 2014 Programme: for Mathematics, Statistics and Operational Research, and for Philosophy. http · to provide, within the supportive and stimulating environment of the collegiate university, a course

  15. Department of Materials University of Oxford

    E-Print Network [OSTI]

    Paxton, Anthony T.

    Objective A report: A detailed design proposal which could be used by a manufacturer/company as the basis with your supervisor. #12;Department of Materials University of Oxford Log book Keep all info in a bound log

  16. 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

  17. The Oxford Programme on the Changing Character of War

    E-Print Network [OSTI]

    Oxford, University of

    The Oxford Programme on the Changing Character of War Seminars Michaelmas Term 2013 Lunchtime Discussions with Changing Character of War Seminars are at 1.00pm, Seminar Room G, Manor Road Building, Oxford Oliveira (Oxford) War and Peace in Angola Tuesday 22nd October Professor Christopher Coker (LSE) Men at War

  18. UK Energy Research Centre Demand Reduction Theme, University of Oxford

    E-Print Network [OSTI]

    UK Energy Research Centre Demand Reduction Theme, University of Oxford The Experience of Carbon Energy Research Centre ­ Demand Reduction Theme Environmental Change Institute Oxford University Centre for the Environment South Parks Road Oxford OX1 3QY www.eci.ox.ac.uk www.ukerc.ac.uk #12;UK Energy Research Centre 2 1

  19. 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.

  20. 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.

  1. 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.

  2. The Oxford Programme on the Changing Character of War

    E-Print Network [OSTI]

    Oxford, University of

    The Oxford Programme on the Changing Character of War Michaelmas Term 2014 Lunchtime Discussions with Changing Character of War Seminars are at 1.00pm, Seminar Room G, Manor Road Building, Oxford A light Slekys, University of Vilnius The Russian-Ukrainian War: Challenges for Military Policy in the Baltic

  3. The Oxford Programme on the Changing Character of War

    E-Print Network [OSTI]

    Oxford, University of

    The Oxford Programme on the Changing Character of War Trinity Term 2013 Lunchtime Discussions with Changing Character of War Seminars are at 1.00pm, Seminar Room G, Manor Road Building, Oxford A light and Political Will Tuesday 21st May Dr Jessica Wolfendale (West Virginia) War Crimes, Character

  4. The Oxford Programme on the Changing Character of War

    E-Print Network [OSTI]

    Oxford, University of

    The Oxford Programme on the Changing Character of War Michaelmas Term 2014 Lunchtime Discussions with Changing Character of War Seminars are at 1.00pm, Seminar Room G, Manor Road Building, Oxford A light, University of Vilnius The Russian-Ukrainian War: Challenges for Military Policy in the Baltic States Tuesday

  5. Oxford Catalysts Group plc | Open Energy Information

    Open Energy Info (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 beingZealand Jump to: navigation, searchOfRoseConcernsCompany OilInformationPre-TaxShelfOxford Catalysts Group

  6. 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.

  7. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Oxford, University of

    OxCORT Oxford Colleges On-line Reports for Tutorials Tutor Role Version 4.5 BSP Training TeamCORT..........................................................................5 Roles in OxCORT..................................................................................5 of Revision Class reports.......................................................8 Report states

  8. Oxford University Final Honour Schools Trinity Term 2007

    E-Print Network [OSTI]

    Goldschmidt, Christina

    Oxford University Final Honour Schools Trinity Term 2007 Mathematics and Statistics Part A: First and Friday of week 9 in Trinity Term, June 21nd and 22rd 2007, but these dates should be regarded

  9. Oxford University Final Honour Schools Trinity Term 2007

    E-Print Network [OSTI]

    Goldschmidt, Christina

    Oxford University Final Honour Schools Trinity Term 2007 Mathematics and Statistics Part A: Second, the examination will be held on Thursday and Friday of week 9 in Trinity Term, June 21st and 22nd 2007, in Ewert

  10. 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.

  11. 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,...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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/

  2. 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,|

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Oxford University Civil Engineering Novel Foundations for Offshore Wind FarmsNovel Foundations for Offshore Wind Farms

    E-Print Network [OSTI]

    Houlsby, Guy T.

    Oxford University Civil Engineering Novel Foundations for Offshore Wind FarmsNovel Foundations for Offshore Wind Farms Prof. Guy Houlsby, Dr Byron Byrne, Dr Chris Martin Oxford University #12;Oxford each turbine does not generate all the time, say 3000) #12;Oxford University Civil Engineering Wind

  14. EUROPEAN STUDIES CENTRE St Antony's College University of Oxford

    E-Print Network [OSTI]

    Oxford, University of

    ) Monday 14th October 5pm ESC/SEESOX Seminar An Insider's View of Greece's Euro-crisis: Why the Road Legitimacy at Times of Crisis Claudia Schrag Sternberg (St. Hugh's, Oxford) On the occasion) #12;Week 3 Tuesday 29th October 5pm ESC Core Seminar Series The Passage to Europe: At the Heart

  15. Amsterdam Oxford Joint Rescue Forces Team Description Paper

    E-Print Network [OSTI]

    Visser, Arnoud

    Amsterdam Oxford Joint Rescue Forces Team Description Paper Virtual Robot competition Rescue van Weelden1 , Chaim Bastiaan1 , Niels Out1 , Olaf Zwennes1 , Sev´aztian Soffia Ot´arola1 , Julian de://www.jointrescueforces.eu Abstract. With the progress made in active exploration, the robots of the Joint Rescue Forces are capable

  16. University of oxford & CUlham sCienCe Centre

    E-Print Network [OSTI]

    Ation entrepreneuriAl connections Aerospace expertise to fusion cooling technology that optimises the heat flow ireland's group (department of engineering) has considerable experience in the cooling technology used supplies, including the uK's 2020 energy targets. "The University of Oxford attracts world

  17. IT Policy, Procedures and Guidance University College, Oxford

    E-Print Network [OSTI]

    Henderson, Gideon

    IT Policy, Procedures and Guidance University College, Oxford Patrick Baird IT and Web Fellow Andy Hamilton IT Manager Helene Augar College Registrar #12;Summary This policy and guidance document. Transgressions (Junior Members) 14 14. Flexible Hours and Working at Home (Staff) 15 15. Revisions to this Policy

  18. University of Oxford Transgender Policy Purpose of this policy

    E-Print Network [OSTI]

    Henderson, Gideon

    University of Oxford Transgender Policy Purpose of this policy 1. The purpose of this policy the process of gender reassignment. The policy and associated guidance give more detail on how the Universitys Equality Policy applies to transgender people. 2. This policy also supports members of the University

  19. TRINITY COLLEGE OXFORD Stipendiary College Lecturership in Philosophy: Further Particulars

    E-Print Network [OSTI]

    Oxford, University of

    TRINITY COLLEGE OXFORD Stipendiary College Lecturership in Philosophy: Further Particulars Teaching of Philosophy at Trinity College Trinity College admits circa eight undergraduate students a year to read one about the College, including Equality Policy documents, please see the College website: http://www.trinity

  20. Oxford University Press 2005 1 Text Mining and Information Extraction

    E-Print Network [OSTI]

    Horn, David

    © Oxford University Press 2005 1 Text Mining and Information Extraction Novel Unsupervised Feature Filtering of Biological Data Roy Varshavsky1,* , Assaf Gottlieb2 , Michal Linial3 and David Horn2 1 School developed for selecting small informative feature subsets in large noisy data. However, unsuper- vised

  1. 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 ...

  2. 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.

  3. 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...

  4. 8'th Bioinformatics Day on "Computational Problems in Biology" October 5 'th 2006 1PM -5 PM in the Oxford Centre for Gene Function, Oxford.

    E-Print Network [OSTI]

    Goldschmidt, Christina

    8'th Bioinformatics Day on "Computational Problems in Biology" October 5 'th 2006 1PM - 5 PM in the Oxford Centre for Gene Function, Oxford. October5'th a Bioinformatics Day with focus on Computer Science to interesting topics and will also be used to announce Genomics/Bioinformatics in the following term: seminars

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Oxford Area Community School District (Michigan) Bonds Case Study

    Broader source: Energy.gov [DOE]

    Michigan’s Oxford Area Community School District entered into an energy savings performance contract and issued limited tax general obligation bonds to fund the up-front costs of almost $3 million of energy-related improvements. Case study is excerpted from Financing Energy Upgrades for K-12 School Districts: A Guide to Tapping into Funding for Energy Efficiency and Renewable Energy Improvements. Author: Merrian Borgeson and Mark Zimring

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. Earl Oxford Hall: A Brief Biography and Wartime History 

    E-Print Network [OSTI]

    Hall, Hal W.

    2008-07-17T23:59:59.000Z

    Appendix 24: Japanese Aircraft in the South Pacific 151 Appendix 25: Japanese Ships in the South Pacific1 155 5 Preface This booklet started as a way to discover and document the life and last few years of the life of Earl Oxford Hall... Another view of the well-stuck airplane, Earl’s AT-6A Texan trainer. Flight training was in the AT-6A and BT-13 trainers. He noted: “the AT-6A is a sweet ship. It handles more smoothly that the BT-13, but doesn’t seem to have quite as much “feel...

  20. Oxford Institute for Energy Studies | Open Energy Information

    Open Energy Info (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 beingZealand Jump to: navigation, searchOfRoseConcernsCompany OilInformationPre-TaxShelfOxford Catalysts

  1. Oxford, North Carolina: Energy Resources | Open Energy Information

    Open Energy Info (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 beingZealand Jump to: navigation, searchOfRoseConcernsCompany OilInformationPre-TaxShelfOxford

  2. New Oxford, Pennsylvania: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall, Pennsylvania:Information Operating Permit ListFacilityOxford,

  3. Village of Oxford, Nebraska (Utility Company) | Open Energy Information

    Open Energy Info (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 YouKizildere IRaghuraji Agro IndustriesTown of Ladoga,planningFlowmeter LoggingVillage ofVillageMorrill,Village of Oxford,

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. 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.

  15. {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}.

  16. University of Oxford Department of Computer Science Job description and selection criteria

    E-Print Network [OSTI]

    Martin, Ralph R.

    University itself. Our annual income in 2009/10 was £879.8m. Oxford is one of Europe's most innovative, Mathematical Institute, the Department of Physics, Department of Plant Sciences, Department of Zoology and training staff in the application process. The role will include reviewing and evaluating existing

  17. University of Oxford Department of Computer Science Job description and selection criteria

    E-Print Network [OSTI]

    Martin, Ralph R.

    University itself. Our annual income in 2009/10 was £879.8m. Oxford is one of Europe's most innovative, Mathematical Institute, the Department of Physics, Department of Plant Sciences, Department of Zoology programming (GP) is a technique that exploits the inherent structure that exists in data, where this structure

  18. Last updated 6 May 2011 Kenya: Balazs Szendroi, University of Oxford, UK, and the Department of

    E-Print Network [OSTI]

    Burton, Geoffrey R.

    Last updated 6 May 2011 Kenya: Balazs Szendroi, University of Oxford, UK, and the Department of Mathematics and Applied Statistics, Maseno University, Kenya Contacts: Professor John Ogonji (Dean), Professor, Kenya, NETwork. The following sessions were held during the course of the visit. (i) Five talks

  19. Chapter 17 Eye-head Gaze shifts Oxford Handbook on Eye Movements

    E-Print Network [OSTI]

    Corneil, Brian D.

    1 Chapter 17 Eye-head Gaze shifts Oxford Handbook on Eye Movements "The Neural Basis of Gaze Shifts" 1. Kinematics of eye-head gaze shifts a. Terminology for describing eye-head gaze shifts b. Variability in eye and head motion during gaze shifts c. Gaze shifts in complex environments d. Bottom

  20. Bottom-up, social innovation for addressing climate change Noam Bergman, University of Oxford

    E-Print Network [OSTI]

    1 Bottom-up, social innovation for addressing climate change Noam Bergman, University of Oxford and practice in the area of bottom-up, social innovation could yield benefits if integrated into wider employing new technical solutions, we identify these as warranting more research, policy and support. Bottom-up

  1. Monte Carlo Methods for Uncertainty Quantification Mathematical Institute, University of Oxford

    E-Print Network [OSTI]

    Giles, Mike

    Lecture 1: Introduction and Monte Carlo basics some model applications random number generation Monte force being outside some specified range Note: if we turn this into a full finite element analysis on the boundary. Mike Giles (Oxford) Monte Carlo methods October 25, 2013 7 / 28 #12;Application 3 In modelling

  2. 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...

  3. 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.

  4. 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.

  5. 1997 Oxford University Press49945002 Nucleic Acids Research, 1997, Vol. 25, No. 24 Information analysis of Fis binding sites

    E-Print Network [OSTI]

    Schneider, Thomas D.

    © 1997 Oxford University Press4994­5002 Nucleic Acids Research, 1997, Vol. 25, No. 24 Information to fit into two successive major grooves on straight B-form DNA, suggesting that the DNA bends

  6. Join the facebook group: `Oxford L.G.B.T.Q. History Month 2012'

    E-Print Network [OSTI]

    Oxford, University of

    Join the facebook group: `Oxford L.G.B.T.Q. History Month 2012' Email: lgbtqof cer@ousu.org 3rd of town and gown. Queer Studies Circle Saturday (2nd Feb), 8pm Old Law Library, Magdalen 4thWeek OU Town Hall 7thWeek OU LGBTQsoc: Drinks Tuesday (26th Feb), 8pm Location TBC Social event for LGBTQ

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Kenya: Balazs Szendroi, University of Oxford, UK, and the Department of Mathematics and Applied Statistics, Maseno University, Kenya

    E-Print Network [OSTI]

    Szendröi, Balázs

    Kenya: Balazs Szendroi, University of Oxford, UK, and the Department of Mathematics and Applied Statistics, Maseno University, Kenya Contacts: Professor John Ogonji (Dean), Professor Omolo Ongati (Head was supported by local funds from MACKNET, the Maths And Computer science, Kenya, NETwork. The following

  20. THE CENTRAL CONCEPTS OF INCLUSIVE FITNESS 3000 word article in the Oxford University Press Encyclopedia of Evolution, January

    E-Print Network [OSTI]

    Taylor, Peter

    1 THE CENTRAL CONCEPTS OF INCLUSIVE FITNESS 3000 word article in the Oxford University Press with alternative traits have lower fitness than "normal" individuals who exhibit the established trait. For example is that the neighbours of the taller individual would have slightly less fitness and, because of limited dispersal

  1. 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...

  2. 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.

  3. This article was downloaded by: [the Bodleian Libraries of the University of Oxford] On: 11 July 2013, At: 09:52

    E-Print Network [OSTI]

    Malhi, Yadvinder

    This article was downloaded by: [the Bodleian Libraries of the University of Oxford] On: 11 July International Journal of Sustainable Development & World Ecology Publication details, including instructions 2013. To cite this article: International Journal of Sustainable Development & World Ecology (2013

  4. "Minds, Brains and Tools" (with a response by Daniel Dennett,) in Hugh Clapin (ed) PHILOSOPHY OF MENTAL REPRESENTATION (Clarendon Press, Oxford, 2002)

    E-Print Network [OSTI]

    Clark, Andy

    OF MENTAL REPRESENTATION (Clarendon Press, Oxford, 2002) Minds, Brains and Tools (Comments on Dennett small texts seemed to fit together and, collectively, to greatly illuminate the shape of Dennett's whole

  5. 1996 Oxford University Press 47094718Nucleic Acids Research, 1996, Vol. 24, No. 23 Logitlinear models for the prediction of splice sites in

    E-Print Network [OSTI]

    Brendel, Volker

    © 1996 Oxford University Press 4709­4718Nucleic Acids Research, 1996, Vol. 24, No. 23 Logitlinear the degree of fit to some average signal pattern around known splice sites in a learning set (e.g., 3

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Assignment 4 BS4a Actuarial Science Oxford MT 2011 IX A.4 Inflation, taxation and project appraisal

    E-Print Network [OSTI]

    Winkel, Matthias

    Assignment 4 ­ BS4a Actuarial Science ­ Oxford MT 2011 IX A.4 Inflation, taxation and project are indexed by reference to the value of a retail price index with a time lag of 8 months. The retail price index value in September 1996 was Q(-8/12) = 200 and in March 1997 was Q(-2/12) = 206. The issue price

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 10/05/2013 10:34Cherwell.org -Oxford / News / Academic / The Hole Truth Page 1 of 2http://www.cherwell.org/news/academic/2013/05/09/the-hole-truth

    E-Print Network [OSTI]

    Gardner, Andy

    Walsh has published 6 articles Photograph: WikiImages The Hole Truth New research by Oxford academics10/05/2013 10:34Cherwell.org - Oxford / News / Academic / The Hole Truth Page 1 of 2http://www.cherwell.org/news/academic Colleges Academic Town Worcester Provost battles with Exeter building plan Teddy Hall Earth Sciences dinner

  2. 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.

  3. A review of "The Oxford Handbook of John Milton" edited by Nicholas McDowell and Nigel Smith

    E-Print Network [OSTI]

    McDowell, Sean H.

    2011-01-01T23:59:59.000Z

    ? essay attempts to o#12;er an original thesis as if the larger collection assumes an audience of both general readers and academic specialists. Indeed, the claim to o#12;er ?original scholarship? becomes a selling point, as in the case of #31;e Oxford... intensi#14;ed the crack-down on perceived copyright infringements, thereby making it more di#11;cult for instructors to include critical readings in their classes. To meet the demand for ready access to scholarship, academic publishers appear to have...

  4. 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.

  5. 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.

  6. 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.

  7. C-3/Oxford/Fish Locomotion/Fish Loco Chap 7/Fish Loco Settings/II/ Chap 7/11-04-09/200 Ecology and Evolution of

    E-Print Network [OSTI]

    Langerhans, Brian

    C-3/Oxford/Fish Locomotion/Fish Loco Chap 7/Fish Loco Settings/II/ Chap 7/11-04-09/200 Ecology and Evolution of Swimming Performance in Fishes: Predicting Evolution with Biomechanics R. Brian Langerhans1, * and David N. Reznick2 NT NINTRODUCTIONTN NINTRODUCTION Residing within the immense diversity of fishes

  8. 1997 Oxford University Press 403408Human Molecular Genetics, 1997, Vol. 6, No. 3 Survey of maximum CTG/CAG repeat lengths in

    E-Print Network [OSTI]

    Kidd, Kenneth

    © 1997 Oxford University Press 403­408Human Molecular Genetics, 1997, Vol. 6, No. 3 Survey survey of CTG/CAG repeat lengths in humans using the RED method; we have determined maximum CTG, potentially unstable trinucleotide repeats. The method uses genomic DNA as a template for the annealing

  9. The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com Tree Physiology 32, 401413

    E-Print Network [OSTI]

    © The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions Research paper Xylem hydraulic adjustment and growth response of Quercus canariensis Willd. to climatic to more xeric conditions at low elevations by reducing radial growth and hydraulic diameter (DH

  10. 1998 Oxford University Press 919932Human Molecular Genetics, 1998, Vol. 7, No. 5 Statistical features of human exons and their flanking

    E-Print Network [OSTI]

    -specific sequence data available today, to facilitate experiments on human molecular genetics and to meet the need© 1998 Oxford University Press 919­932Human Molecular Genetics, 1998, Vol. 7, No. 5 Statistical features of human exons and their flanking regions M. Q. Zhang Cold Spring Harbor Laboratory, PO Box 100

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. Results of the radiological survey at the former Alba Craft Laboratory site properties, Oxford, Ohio (OXO001)

    SciTech Connect (OSTI)

    Murray, M.E.; Brown, K.S.; Mathis, R.A.

    1993-03-01T23:59:59.000Z

    At the request of the US Department of Energy (DOE), a team from Oak Ridge National Laboratory conducted a radiological survey at the former Alba Craft Laboratory Site Properties, Oxford, Ohio. The survey was performed in July and September of 1992. The purpose of the survey was to determine whether the property was contaminated with radioactive residues, primarily [sup 238]U, from uranium machining operations conducted for National Lead of Ohio, a prime Atomic Energy Commission contractor. The survey included scan measurement of direct radiation levels inside and outside the former laboratory, outdoors on eight properties adjoining the former laboratory, and the city right-of-way adjacent to the surveyed properties. Radionuclide concentrations were determined in outdoor surface and subsurface soil samples taken from each property and the exterior of the laboratory. Fixed surface residual radioactivity was measured inside the laboratory and outside the building. Air samples were collected, direct exposure was measured, and samples were collected to measure transferable radioactivity inside the building. Results of the survey indicate areas where surface and soil contamination level s are above the DOE guidelines for uncontrolled areas.

  17. 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

  18. 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

  19. 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...

  20. Blackwell Publishing, Ltd.Oxford, UKAPELAsian-Pacific Economic Literature0818-9935 2005 Asia Pacific School of Economics and Government, The Australian National University and Blackwell Publishing Asia Pty LtdNovember 2005192ORIGINAL ARTICLEROLAND-HOLST a

    E-Print Network [OSTI]

    Kammen, Daniel M.

    18 Blackwell Publishing, Ltd.Oxford, UKAPELAsian-Pacific Economic Literature0818-9935© 2005 Asia Pacific School of Economics and Government, The Australian National University and Blackwell Publishing and ITS NEIGHBOURSASIAN-PACIFIC ECONOMIC LITERATURE People's Republic of China and its Neighbours

  1. 28/05/2009 16:25Global links will breed more dangerous parasites -University of Oxford Page 1 of 2http://www.ox.ac.uk/media/news_stories/2009/090528_3.html

    E-Print Network [OSTI]

    West, Stuart

    28/05/2009 16:25Global links will breed more dangerous parasites - University of Oxford Page 1 of 2http://www.ox.ac.uk/media/news_stories/2009/090528_3.html Global links will breed more dangerous that as the world becomes more connected so natural selection will favour more dangerous parasites. The team, from

  2. Ecology to evolution, marine biology to molecular biology: Oxford's prestigious Life Science journals uncover the extraordinary scope of life on our planet. Our diverse range of titles includes Annals of Botany, the Journal of

    E-Print Network [OSTI]

    Kaski, Samuel

    service including offsite access (46 titles) 1. Forest & Conservation History and Environmental History Review merged in 1996 to become Environmental History 2. Previously named Journal of Electron Microscopy library. The Oxford Journals Life Sciences Collection 2014 Impact Factors taken from the 2012 Journal

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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 ...

  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. Oxford System 400

    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 and BiofuelsOversight Board TheOverview of thethe

  1. 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.

  2. 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.

  3. 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.

  4. The Oxford-Dartmouth Thirty Degree Survey II: Clustering of Bright Lyman Break Galaxies - Strong Luminosity Dependent Bias at z=4

    E-Print Network [OSTI]

    Paul D. Allen; Leonidas A. Moustakas; Gavin Dalton; Emily MacDonald; Chris Blake; Lee Clewley; Catherine Heymans; Gary Wegner

    2005-05-02T23:59:59.000Z

    We present measurements of the clustering properties of bright ($L>L_{*}$) z$\\sim$4 Lyman Break Galaxies (LBGs) selected from the Oxford-Dartmouth Thirty Degree Survey (ODT). We describe techniques used to select and evaluate our candidates and calculate the angular correlation function which we find best fitted by a power law, $\\omega(\\theta)=A_{w}\\theta^{-\\beta}$ with $A_{w}=15.4$ (with $\\theta$ in arcseconds), using a constrained slope of $\\beta=0.8$. Using a redshift distribution consistent with photometric models, we deproject this correlation function and find a comoving $r_{0}=11.4_{-1.9}^{+1.7}$ h$_{100}^{-1}$ Mpc in a $\\Omega_m=0.3$ flat $\\Lambda$ cosmology for $i_{AB}\\leq24.5$. This corresponds to a linear bias value of $b=8.1_{-2.6}^{+2.0}$ (assuming $\\sigma_{8}=0.9$). These data show a significantly larger $r_{0}$ and $b$ than previous studies at $z\\sim4$. We interpret this as evidence that the brightest LBGs have a larger bias than fainter ones, indicating a strong luminosity dependence for the measured bias of an LBG sample. Comparing this against recent results in the literature at fainter (sub-$L_{*}$) limiting magnitudes, and with simple models describing the relationship between LBGs and dark matter haloes, we discuss the implications on the implied environments and nature of LBGs. It seems that the brightest LBGs (in contrast with the majority sub-$L_{*}$ population), have clustering properties, and host dark matter halo masses, that are consistent with them being progenitors of the most massive galaxies today.

  5. 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

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. DEGREE CEREMONY UNIVERSITY OF OXFORD

    E-Print Network [OSTI]

    Oxford, University of

    and lined with petrol blue silk MA Master of Arts, black silk lined with crimson or shot crimson silk

  12. Adrian Cooper CEO, Oxford Economics

    Gasoline and Diesel Fuel Update (EIA)

    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 for On-Highway4,1,50022,3,,,,6,1,9,1,50022,3,,,,6,1,Decade Year-0E (2001)gasoline prices4 Oil

  13. Oxford Innovation | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,Owls Head,County,

  14. Oxford Solar | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,Owls Head,County,Solar

  15. Oxford, Ohio, Site Fact Sheet

    Office of Legacy Management (LM)

    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 AprilA groupTuba City, Arizona, DisposalFourthN V O 1 8 7 +NewAugust 4, 1992DOCEOxford,

  16. OxfordRoadOxfordRoadOxfordRoad UpperBrookStreetUpperBrookStreet

    E-Print Network [OSTI]

    Lane Platt Lane UpperLloydStreet HartLane Claremont Road Mauldeth RoadMauldeth Road West Albert Road Coupland Chapel 43. Roby URC 44. Quadria Jilamia Islamic Centre 45. Platt Lane Methodist Church 46. Holy Trinity, Platt Church of England 47. Platt Fields Park, open space with a lake. 48. Allen Hall 49. The Islah

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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)

  19. 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).

  20. 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.

  1. 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...

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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 $z\\lesssim 1$.

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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...

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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

  20. 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 ...

  1. 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...

  2. 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

  3. 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...

  4. 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

  5. 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.

  6. 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.

  7. UNIVERSITY OF OXFORD Department of Physics

    E-Print Network [OSTI]

    Crowther, Paul

    . If this butchery goes ahead, the crisis threatens to rip the heart out of many 5 and 5* physics departments UK write about the current crisis that threatens those subjects supported by the new Science and Technology and astronomy in the UK. It will provoke crisis in many UK physics departments, and it will severely restrict

  8. Report - Academic Practice Conference in Oxford, 2009

    E-Print Network [OSTI]

    Arnold, Richard

    2009-01-01T23:59:59.000Z

    -formal discussion sessions, addressing subjects of particular shared interest; a private reception for early career academics (doctoral students, postdoctoral researchers, research staff and new lecturers); and hopefully a third strand – narrative histories...

  9. Delivered by Ingenta to: University of Oxford

    E-Print Network [OSTI]

    Guo, John Zhanhu

    (ICL), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710, USA 5

  10. SATURDAY 10 NOVEMBER 2012 EXAM SCHOOLS, OXFORD

    E-Print Network [OSTI]

    Melham, Tom

    LLP Mishcon de Reya Morgan Cole LLP Morgan Lewis & Bockius LLP Morrison & Foerster (UK) LLP Nabarro Skadden, Arps, Slate, Meagher and Flom (UK) LLP Slaughter and May SNR Denton UK LLP Stephenson Harwood LLP

  11. Oxford University Department of Materials Academic Committee

    E-Print Network [OSTI]

    Paxton, Anthony T.

    reported on the E(M)EM Working Group and Standing Committee re. the proposed changes to the EEM course for the proposed new EEM course, and the Department of Engineering Science has not yet decided finally on its format. In the immediate future, the EEM course will remain as a Joint Honours course. It was agreed

  12. UNIVERSITY OF OXFORD Department of Statistics

    E-Print Network [OSTI]

    Goldschmidt, Christina

    mathematics course with the ability to pursue probability and statis- tics in depth, and reflects the strong education here will equip you well for your future, wherever that may be. We hope you find your time

  13. In Bioinformatics (to appear), Oxford University Press

    E-Print Network [OSTI]

    Pavlovic, Vladimir

    and gene discovery in new genomic sequences is one of the most timely com­ putational questions addressed successfully in many whole­ genome analysis projects. As the number of such systems grows the need was presented at Computational Genomics 2000, Baltimore, MD, Nov. 2000. Portions of this research were con

  14. In Bioinformatics (to appear), Oxford University Press

    E-Print Network [OSTI]

    Pavlovic, Vladimir

    and gene discovery in new genomic sequences is one of the most timely com- putational questions addressed successfully in many whole- genome analysis projects. As the number of such systems grows the need was presented at Computational Genomics 2000, Baltimore, MD, Nov. 2000. Portions of this research were con

  15. Oxford FlexAL SOP Introduction

    E-Print Network [OSTI]

    Reif, Rafael

    Chamber 1 from the drop down menu. Adjust the process temperature using the Table Heater setting. #12 and click OK. #12;The recipe steps will be displayed on the screen. Click on the Repeat Step

  16. Oxford, Massachusetts: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,Owls

  17. Oxford, Michigan: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,OwlsMichigan: Energy

  18. Oxford, Mississippi: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,OwlsMichigan:

  19. Oxford, Ohio: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,OwlsMichigan:Ohio: Energy

  20. Undergraduate Handbook 2013-14 Welcome to Oxford, or welcome back to Oxford!

    E-Print Network [OSTI]

    will need to enter search parameters as follows: select "By year group" on the left hand side of the screen dates (of teaching terms, course-work submission deadlines, field trips and so on), that you will need

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. 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.

  13. Attitudes toward offshore oil development: A summary of current evidence

    E-Print Network [OSTI]

    Gramling, R; Freudenburg, Wm R

    2006-01-01T23:59:59.000Z

    Nigeria: the political economy of oil. Oxford: Oxford University Press for the Oxford Institute for Energy

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Earl Oxford Hall: A Brief Biography and Wartime History

    E-Print Network [OSTI]

    Hall, Hal W.

    2010-08-12T23:59:59.000Z

    in Japanese hands up to August 1942. On August 7, 1942, U. S. troops landed on Guadalcanal. Resistance was fierce, with the island not completely secured until February 9, 1943. Henderson Field was secured and made operational for air defense by August... 17th . Throughout the fall, Henderson was under constant attack. On October 14th, the Japanese all but destroyed the field in massive bombing and naval bombardment attacks, but by late November or early December, Henderson Field was secure...

  4. Oxford Institute for Energy Studies Natural Gas Research Programme

    E-Print Network [OSTI]

    Texas at Austin, University of

    demand and price dynamics than by crude oil or oil product prices. The author, Dr Michelle Michot Foss concludes that the relationship between petroleum liquids and natural gas prices going forward will be less, this means that as long as crude oil prices remain significantly in excess of $35/bbl, European gas markets

  5. Earl Oxford Hall: A Brief Biography and Wartime History

    E-Print Network [OSTI]

    Hall, Hal W.

    2008-07-17T23:59:59.000Z

    the lead element pilots are named in the mission reports. On July 19, 1942, Captain Hall, with his crew and several others, left for New Caledonia. The route followed is shown in a map of the South Pacific (Map 1). The planes flew form Hawaii..., Military Services Information Project 77 4 Appendix 16: USAAF Missing Air Crew Report, 1943 85 Appendix 17: USAAF A-2 Periodic Report 91 Appendix 18: 42 nd Bombardment Squadron (H): Missions 18 July 1942 – 1 February 1943 97 Appendix 19...

  6. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Oxford, University of

    of term procedures for Tutorial Office..........................................15 End of term procedures To enter College bank details..............................................................23 7. Enter Or Maintain Teaching Hours Weighting Data ................................25 To enter weighting data

  7. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Oxford, University of

    of term procedures for Tutorial Office..........................................15 End of term procedures To enter College bank details..............................................................25 7. Enter Or Maintain Teaching Hours Weighting Data ................................27 To enter weighting data

  8. IARU GSP @ University of Oxford 2013/12/18 120132

    E-Print Network [OSTI]

    Miyashita, Yasushi

    )Literature Exeter college 20132 2013/12/18 6 Home university Major UC Berkeley, 4 Copenha gen, 3 ANU (Autraria security · Economic models · Energy Oil · International development · Poverty · Aid & trade? Essay International development Technology Resources Behavior Poverty Internet power EU politics Food security general

  9. Harry Potter, Oxford and Nuclear Energy | Department of Energy

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

    Affairs Specialist, Office of Public Affairs Dr. Peter Lyons, the Assistant Secretary for Nuclear Energy at the Energy Department and the U.S. government's foremost expert on...

  10. University of Oxford Energy Toolkit2011/12

    E-Print Network [OSTI]

    Melham, Tom

    to reduce its energy consumption, due to: The rising cost of electricity, gas and oil Increasing legislative and cut your energy bills. The toolkit will help you to reduce electricity, gas and oil consumption dioxide we emit under the Government's Carbon Reduction Commitment (CRC) Energy Efficiency Scheme The need

  11. DMAC 32 SHORTENED MINUTES Oxford University Department of Materials

    E-Print Network [OSTI]

    Paxton, Anthony T.

    according to different scales as compared to the EEM / MEM students and that the classification boundary for a first was lower in E & M than in EEM / MEM." 3. Shortened Minutes There were no confidential items

  12. annual meeting oxford: Topics by E-print Network

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

    3.1 93rd Annual General Meeting - June 4, 2009 Marianne asked - 10 Review Engagement Report - Dr. Bryan Harvey, President Elect Dr. Bryan Harvey reviewed Saskatchewan,...

  13. Vol. 1 no. 1 2006 Oxford University Press 2006 1

    E-Print Network [OSTI]

    Kolodny, Rachel

    describe the use of a particular struc- ture fragment library, denoted here as KL-strings, for the 1D immediate applications towards fast structure recognition, and for fold prediction and classification

  14. Exeter College. Oxford 02.03.12 Max Fordham LLP

    E-Print Network [OSTI]

    Flynn, E. Victor

    .3 Regional and Local Policy 5 3.0 Energy Strategy 6 3.1 Our Approach 6 3.2 Using Less Energy 7 3.3 Supplying College. The Sustainability and Energy Strategy sections set out the requirements for sustainable building 267 5161 www.smaxfordham.com A New Quad at Walton Street Sustainability, Energy and Noise Statement

  15. Wavelet compression for unsteady CFD data Oxford University Computing Laboratory

    E-Print Network [OSTI]

    Giles, Mike

    in compressing the periodic data arising from 3D stator/rotor and utter applications. 1 #12;1 Fourier compression compression can only be performed as a post-processing step. Also, the reconstruction at a particular instant

  16. DMAC 36 SHORTENED MINUTES Oxford University Department of Materials

    E-Print Network [OSTI]

    Paxton, Anthony T.

    comprising CMB (Chair), AJW, JMS, SCB, and JaMS will report to DMAC by MT06. If at their initial meeting

  17. DMAC 34 SHORTENED MINUTES Oxford University Department of Materials

    E-Print Network [OSTI]

    Paxton, Anthony T.

    comprising CMB (Chair), AJW, JMS, SCB, and JaMS will report to DMAC by MT06. If at their initial meeting

  18. OxfordMusicOnline (GroveMusicOnline)

    E-Print Network [OSTI]

    and links on the left-hand side: Search terms are highlighted in yellow. A "Search within this article under the call number ML102.J3 N48 2001. Enter keyword(s) in either open field and click the box or choose Advanced Search links for more options, such as combining keywords. From the opening screen

  19. Chapman of XSD Wins Oxford Cryosystems Poster Prize

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

    Appointed ALD for Photon Sciences APS, Other DOE Labs Help Develop New Cancer Fighting Drug Paper on Fast Pharmaceuticals by APS Authors Featured in New Journal APS News Archives:...

  20. UNIVERSITY PRBSS Oxford University Press, Inc., publishes works that further

    E-Print Network [OSTI]

    Levinson, David M.

    Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece ifwe agree that congestion wastes time, is minimizing congestion the most appropriate public policy goal (Taylor 2003)? Do measures of congestion provide the basis for policy prescriptions? We argue

  1. EUROPEAN STUDIES CENTRE St Antony's College University of Oxford

    E-Print Network [OSTI]

    Oxford, University of

    Turkey and European Union Energy Policy Hasan Murat Mercan (Turkish Deputy Minister for Energy: http://www.sant.ox.ac.uk/esc/fanddregistration.html Week 3 Monday 6th May 5pm SEESOX Seminar Serbia Dejan Popovi (Ambassador of Serbia to the United Kingdom) Discussant: Elizabeth Roberts (Trinity College

  2. Oxford County, Maine: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,Owls Head,County, Maine:

  3. Oxford, United Kingdom: Energy Resources | Open Energy Information

    Open Energy Info (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 YouKizildere I Geothermal Pwer PlantMunhall,Missouri:EnergyOssian, New York: EnergyOuachitaOwasso,OwlsMichigan:Ohio:

  4. City of Oxford, Georgia (Utility Company) | Open Energy Information

    Open Energy Info (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 directedAnnual Siteof EnergyInnovationin UrbanCity of Okolona, Mississippi (UtilityCity ofCity ofCityCity

  5. City of Oxford, Mississippi (Utility Company) | Open Energy Information

    Open Energy Info (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 directedAnnual Siteof EnergyInnovationin UrbanCity of Okolona, Mississippi (UtilityCity ofCity

  6. DOE - Office of Legacy Management -- Oxford_FUSRAP

    Office of Legacy Management (LM)

    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 AprilA group currentBradleyTableSelling Corp - CTOregon Metallurgical Corp - OROhio

  7. DOE - Office of Legacy Management -- Oxford OH Site - OH 22

    Office of Legacy Management (LM)

    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 AprilA group currentBradleyTableSelling CorpNew MexicoUtah MexicanNiagara

  8. City of Oxford, Kansas (Utility Company) | Open Energy Information

    Open Energy Info (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 beingZealand JumpConceptual Model, clickInformation Smyrna Beach, Florida (UtilityOnida,

  9. The Danger of Wishing for Chaos Patrick E McSharry, Department of Engineering Science, University of Oxford, Oxford

    E-Print Network [OSTI]

    McSharry, Patrick E.

    The Danger of Wishing for Chaos Patrick E McSharry, Department of Engineering Science, University for the Analysis of Time Series, London School of Economics, London, WC2A 2AE, UK THE DANGER OF WISHING FOR CHAOS into their particular fields of expertise. #12;This division has and continues to present an unfortunate danger

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. REGROWTH BEHAVIOR OF THREE DIFFERENT DAMAGE STRUCTURES IN P+ IMPLANTED AND SUBSEQUENTLY LASER ANNEALED Si

    E-Print Network [OSTI]

    Sadana, D.K.

    2012-01-01T23:59:59.000Z

    94720 +Department of Metallurgy University of Oxford OxfordUK) through Department of Metallurgy, Oxford. REFERENCES G.

  1. Variant surface glycoprotein RNA interference triggers a precytokinesis cell cycle arrest

    E-Print Network [OSTI]

    Schnaufer, Achim

    Rudenko*§ *Peter Medawar Building for Pathogen Research, University of Oxford, South Parks Road, Oxford OX

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. 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 $\\{a^2,a\\phi\\}\\sim\\sqrt{4n_1+1}\\pm\\sqrt{4n_2+1}$.

  7. 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.

  8. 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

  9. 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\

  10. 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.

  11. 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.

  12. 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.

  13. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    , Olivia D'Aoust , Olivier Sterck§ May 2014 Abstract We aim at understanding the triggers of electoral, Electoral violence, Polarization, Demobilization, Burundi JEL Classification: D74, O11, O17, O55 We thank, Antonio Estache, James Fenske, Anke Hoeffler, Davy Paindaveine, Cyrus Samii and Philip Verwimp

  14. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    of this research was conducted during my stay at the National Team for the Acceleration of Poverty Reduction (TNP2K Working Paper WPS/2014-29 #12;1 Introduction Why do the poor stay poor? One explanation for poverty traps is the prevalence of con- spicuous consumption among the poor which hinders investments and savings (Neeman and Moav

  15. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    .enquiries@economics.ox.ac.uk . W: www.csae.ox.ac.uk CSAE Working Paper WPS/2014 18 Employment Creation, Poverty and the Structure the evidence is reviewed as to how far the more rapid growth of recent years has translated into poverty reduction and how these poverty measures link to job creation. There is evidence that the headcount measure

  16. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    Dercon1 Abstract With serious impacts of climate change looming in a few decades, but current poverty still high in the developing world, we ask how to spend development aid earmarked for the poor. Poverty deliver large scale poverty reduction? Can aid be used for effective poverty reduction now without

  17. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    accelerations on poverty and inequality in Indonesia using a new panel dataset covering 26 provinces over of the economy. We find that growth in non-mining significantly reduces poverty and inequality. In contrast, overall growth and growth in mining appears to have no effect on poverty and inequality. We also identify

  18. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    .enquiries@economics.ox.ac.uk . W: www.csae.ox.ac.uk 1 CSAE Working Paper WPS/2014 17 Growth, Inequality, and Poverty in Sub Saharan of income and inequality changes to poverty reduction for a large number of countries in sub Saharan Africa (SSA). The study begins by shedding light on SSA's progress on poverty. Next, it presents data on how

  19. Centre for the Study of African Economies Department of Economics . University of Oxford . Manor Road Building . Oxford OX1 3UQ

    E-Print Network [OSTI]

    Oxford, University of

    commodities. A sustained increase in the price of renewables (wool) reduces inequality whreas the same for non-renewable that one of the key empirical foundations of the Engerman and Sokoloff argument is that inequality in Latin America was higher than North America. Perhaps, but what about Europe? Williamson (2010) and Milanovic et

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. P. MCK Cryst. Res. Technol. 35 (2000) 529-540 Department of Materials, University of Oxford

    E-Print Network [OSTI]

    Moeck, Peter

    Comparison of Experiments and Theories for Plastic Deformation in thermally processed GaAs Wafers Different single crystal X-ray transmission topography, scanning infrared polariscopy, visible light interferometry that reduces the yield of electronic devices in manufacturing processes on an industrial scale [KIYAMA et al

  17. CopyrightOxfordUniversityPress2006v1.0 Statistical Mechanics

    E-Print Network [OSTI]

    Sethna, James P.

    in physics. Indeed, many physicists in their later careers are now taking excursions into these other finds Maxwell relations for the stock market, or Clausius­Clapeyron equations appli- cable applications of statistical mechanics: random matrix theory, stock-market volatility, the KAM theorem, Shannon

  18. Compact Manifolds with Holonomy Spin(7) Christine Taylor, Balliol College, Oxford

    E-Print Network [OSTI]

    Joyce, Dominic

    with Holon- omy Spin(7) 8 2.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2

  19. Teaching natural philosophy and mathematics at Oxford and Cambridge 1500-1570

    E-Print Network [OSTI]

    Hannam, James

    2008-04-22T23:59:59.000Z

    to dip into the lists rather than work with them systematically. Now, thanks to the care and dedication of Elisabeth Leedham-Green, among other scholars, these lists have been brought to print. The most fruitful source of booklists is the inventories... . S. Leedham-Green, Books in Cambridge Inventories: Books from the Vice-Chancellor’s Court Probate Inventories in the Tudor and Stuart Periods, 2 vols. (Cambridge, 1986). 46 F. J. Norton, “The Library of Bryan Rowe, Vice-Provost of King’s d. 1521...

  20. NERC Research Experience Placement Scheme Summer 2012 Department of Earth Sciences, University of Oxford

    E-Print Network [OSTI]

    Henderson, Gideon

    to the natural environment where it is a potential tracer of this leakage. Uranium is relative mobile; exploration of other sample types (soils etc.); and/or calculation of the production rates of other rare

  1. STORING ARB HYUNGSOK AHN, Credit Agricol Lazard Financial Products & U. of Oxford, UK

    E-Print Network [OSTI]

    DANILOVA, Imperial College, UK GLEN SWINDLE, Constellation Power Source, USA In natural gas markets, demand

  2. 1IFM'07, Oxford, UK, July 3-5, 2007 Translating FSP into LOTOS and

    E-Print Network [OSTI]

    Joseph Fourier Grenoble-I, Université

    -to-use notation ­ basic verification means (LTSA) animation and LTL property checking · LOTOS is an ISO standard: ­ FSP is a simple yet expressive notation ­ CADP is a rich toolbox to be used jointly with LTSA

  3. Status of T2K Target 2nd Oxford-Princeton High-Power Target Workshop

    E-Print Network [OSTI]

    McDonald, Kirk

    Graphite (ToyoTanso IG-43) Current Target Design Helium cooling Graphite to titanium diffusion bond 47.0 46-Power Target Workshop Mike Fitton IG43 Graphite diffusion bonded into Ti-6Al-4V titanium, Special Techniques Group at UKAEA Culham Diffusion Bond + Graphite-Graphite bonding test Aluminium intermediate layer

  4. OxfordCentreforTectonicandMetallogenicStudies For details concerning OCTAMS initiatives, or undergraduate/postgraduate

    E-Print Network [OSTI]

    Henderson, Gideon

    the relationships between the pattern of global tectonics and the nature and distribution of the Earth's mineral elsewhere in the world. · OCTAMS hopes to interact closely with industrial partners from both the minerals. The nature and distribution of both metal and petroleum resources will be examined in the context

  5. The Queen's College Guide to Driving and Parking in and around Oxford

    E-Print Network [OSTI]

    Capdeboscq, Yves

    Street (182 spaces) ­ City Centre · Abbey Place (80 spaces) - Opposite the ice-rink · Gloucester green (100 spaces) - Underground close to the centre · Oxpens (56 spaces) - Next to the ice-rink · St

  6. David J. Malan 33 Oxford Street Cambridge MA 02138 USA +1-617-523-0925

    E-Print Network [OSTI]

    Liu, X. Shirley

    (Ph.D.), Computer Science. Research in cybersecurity and digital forensics with focus on detection ­ 2004 Master of Science (S.M.), Computer Science. Research in sensor networks for emergency medical care, multivariate calculus, and linear algebra. research interests Cybersecurity, digital forensics, botnets

  7. The origins .... of life A sermon delivered in The Queen's College, Oxford

    E-Print Network [OSTI]

    Capdeboscq, Yves

    on with, you know, this origin of life business. More scuffling, more coughs. But why? Simply because

  8. Summary report of flexible working interviews held in the Department of Zoology, University of Oxford.

    E-Print Network [OSTI]

    West, Stuart

    . For the purposes of the EIA, research also involved a staff survey (targeted towards key groups of staff outside the Department of Zoology in order to provide evidence for an Equality Impact Assessment (EIA) of the University of Zoology, both academic and non-academic). The flexible working survey remained open for 3 weeks

  9. Monte Carlo Methods for Uncertainty Quantification Mathematical Institute, University of Oxford

    E-Print Network [OSTI]

    Giles, Mike

    methods October 25, 2013 7 / 28 Application 3 In modelling groundwater flow in nuclear waste repositories: Introduction and Monte Carlo basics some model applications random number generation Monte Carlo estimation specified range Note: if we turn this into a full finite element analysis, then the computational cost

  10. Materials Science at Oxford is an interdisciplinary subject that makes use of knowledge from Physics,

    E-Print Network [OSTI]

    Oxford, University of

    for telecommunications, semiconductors and other materials for photovoltaic energy generation, and silicon microchips for the information revolution. Materials Science is critical to the practical realisation of our desire to generate power by nuclear fusion. It is at the core of nanotechnology, the production of machines and devices

  11. Microsoft PowerPoint - Oxford_MiniBooNE_and_SterileNus.ppt

    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 82981-1cnHighand RetrievalsFinalModule8.pptStates AOnline0, 2009HAB and Public

  12. BY ALYSSA SCHNUGG Staff Writer

    E-Print Network [OSTI]

    Tchumper, Gregory S.

    and The Strong Heart Clinic into Oxford Heart Consultants. Oxford Heart Consultants continues to offer exceptional comprehensive care in the heart of Oxford by providing general cardiology, interventional cardiology, advanced heart failure, peripheral vascular disease and arrhythmia management. Oxford Heart

  13. Study Protocol: The Back pain Outcomes using Longitudinal Data (BOLD) Registry

    E-Print Network [OSTI]

    2012-01-01T23:59:59.000Z

    modeling for health economic evaluation. Oxford: OxfordSonnad SS, Polsky D: Economic evaluation in clinical trials.

  14. To appear in Proceedings of the Workshop on Formal Techniques for Hardware and Hardware-like Systems, Marstrand, Sweden, June 1998.

    E-Print Network [OSTI]

    Pace, Gordon J.

    2 1 University of Malta, Msida MSD 06, Malta 2 University of Oxford, Parks Road, Oxford, UK Abstract

  15. 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...

  16. 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.

  17. 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...

  18. 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.

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. 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.

  4. "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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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).

  12. 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

  13. 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.

  14. The Twisted Matrix: Dream, Simulation or Hybrid? to appear in C. Grau (ed) Philosophical Essays on the Matrix (Oxford University

    E-Print Network [OSTI]

    Clark, Andy

    ³The Twisted Matrix: Dream, Simulation or Hybrid?² to appear in C. Grau (ed) Philosophical Essays://whatisthematrix.warnerbros.com/rl_cmp/phi.html The Twisted Matrix: Dream, Simulation or Hybrid1? 1. Ambivalence "The Matrix is a computer in a world of persisting, external, independent people, cities, cars and objects, and you yourself

  15. R Present address: Department of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, England.

    E-Print Network [OSTI]

    Abrahams, I. David

    disc, with several out-of-plane modes, excited at one point along the edge by a dry-friction force individual wheels that are excited by the dry friction forces that are associated with a sliding is presumed to arise from lateral crabbing of the wheels across the rail head. This induces a lateral friction

  16. The Machine Stops by E.M. Forster First published in the Oxford and Cambridge Review in 1909

    E-Print Network [OSTI]

    Nissenbaum, Helen

    THE AIR-SHIP Imagine, if you can, a small room, hexagonal in shape, like the cell of a bee. It is lighted for a visit. "The air-ship barely takes two days to fly between me and you." "I dislike air-ships." 2 #12;"Why no ideas in an air-ship." "I do not get them anywhere else." "What kind of ideas can the air give you?" He

  17. Proceedings of: ''Formal Methods Europe'', March 1996, Oxford, UK, LNCS 1051, Springer Automatic Verification of a Hydroelectric Power

    E-Print Network [OSTI]

    Tronci, Enrico

    Verification of a Hydroelectric Power Plant 1 Rosario Pugliese Enrico Tronci Dip. di Scienze dell@univaq.it Abstract. We analyze the specification of a hydroelectric power plant by ENEL (the Italian Electric Company we report on the analysis of a hydroelectric power plant by ENEL (the Italian Electric Company). Our

  18. UK 8m Users Group meeting, Oxford, 10 October 2007 Minutes prepared originally by Jacco van Loon, 2 November 2007.

    E-Print Network [OSTI]

    Crowther, Paul

    Operations), Simon Morris (Gemini Science Committee, ESO OPC Chair), Marie Lemoine-Busserolle, Mark Wilkinson, Jim Dunlop, Isobel Hook, Matt Jarvis, Rachel Johnson, Pat Roche, Ray Sharples, Aprajita Verma

  19. Ann. Occup. Hyg., Vol. 53, No. 6, pp. 551560, 2009 The Author 2009. Published by Oxford University Press

    E-Print Network [OSTI]

    California at Berkeley, University of

    not elevated among millers). Results from linear mixed-effects models of levels of U-Nap, U-Phe, OH-Phe, and OH; exposure; PAH; urine INTRODUCTION Asphalt (also referred to as bitumen) is a by-product of petroleum refining that is widely used to pave roads. Road-paving workers are exposed to emis- sions from hot asphalt

  20. 178 VI. CLASSICAL PROBABILITY AND ITS RENAISSANCE 11. M. Tribus, Rational Descriptions, Decisions and Designs, p. 130. Oxford: Pergamon,

    E-Print Network [OSTI]

    Fitelson, Branden

    . However, the classical theory lacked guidelines for the identifica- tion of a balance of evidence gives us few guidelines for the actual determination of logical probability. Finally, we consider Carnap, quantitative logical relation, called degree of confirmation (d.c.), to measure the support one statement lends