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1

New Nuclear Physics for Big Bang Nucleosynthesis  

E-Print Network (OSTI)

We discuss nuclear reactions which could play a role in Big Bang Nucleosynthesis (BBN). Most of these reactions involve lithium and beryllium isotopes and the rates for some of these have not previously been included in BBN calculations. Few of these reactions are well studied in the laboratory. We also discuss novel effects in these reactions, including thermal population of nuclear target states, resonant enhancement, and non-thermal neutron reaction products. We perform sensitivity studies which show that even given considerable nuclear physics uncertainties, most of these nuclear reactions have minimal leverage on the standard BBN abundance yields of 6Li and 7Li. Although a few have the potential to alter the yields significantly, we argue that this is unlikely.

Richard N. Boyd; Carl R. Brune; George M. Fuller; Christel J. Smith

2010-08-04T23:59:59.000Z

2

New nuclear physics for big bang nucleosynthesis  

SciTech Connect

We discuss nuclear reactions which could play a role in big bang nucleosynthesis. Most of these reactions involve lithium and beryllium isotopes and the rates for some of these have not previously been included in BBN calculations. Few of these reactions are well studied in the laboratory. We also discuss novel effects in these reactions, including thermal population of nuclear target states, resonant enhancement, and nonthermal neutron reaction products. We perform sensitivity studies which show that even given considerable nuclear physics uncertainties, most of these nuclear reactions have minimal leverage on the standard BBN abundance yields of {sup 6}Li and {sup 7}Li. Although a few have the potential to alter the yields significantly, we argue that this is unlikely.

Boyd, Richard N. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Brune, Carl R. [Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States); Fuller, George M. [Department of Physics, University of California, San Diego, La Jolla, California 92093-0319 (United States); Smith, Christel J. [Physics Department, Arizona State University, Tempe, Arizona 85287-1404 (United States)

2010-11-15T23:59:59.000Z

3

Dark/visible parallel universes and Big Bang nucleosynthesis  

SciTech Connect

We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds, the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN), baryon asymmetries, cosmic microwave background (CMB) bounds, galaxy dynamics, together with the Standard Model assumptions, help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

Bertulani, C. A.; Frederico, T.; Fuqua, J.; Hussein, M. S.; Oliveira, O.; Paula, W. de [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil); Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce TX 75429 (United States); Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP, Brazil and Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal); Departamento de Fisica, Instituto Tecnologico de Aeronautica, DCTA 12.228-900, Sao Jose dos Campos, SP (Brazil)

2012-11-20T23:59:59.000Z

4

Dark/visible parallel universes and Big Bang nucleosynthesis  

Science Journals Connector (OSTI)

We develop a model for visible matter-dark matter interaction based on the exchange of a massive gray boson called herein the Mulato. Our model hinges on the assumption that all known particles in the visible matter have their counterparts in the dark matter. We postulate six families of particles five of which are dark. This leads to the unavoidable postulation of six parallel worlds the visible one and five invisible worlds. A close study of big bang nucleosynthesis (BBN) baryon asymmetries cosmic microwave background (CMB) bounds galaxy dynamics together with the Standard Model assumptions help us to set a limit on the mass and width of the new gauge boson. Modification of the statistics underlying the kinetic energy distribution of particles during the BBN is also discussed. The changes in reaction rates during the BBN due to a departure from the Debye-Hueckel electron screening model is also investigated.

C. A. Bertulani; T. Frederico; J. Fuqua; M. S. Hussein; O. Oliveira; W. de Paula

2012-01-01T23:59:59.000Z

5

The NACRE Thermonuclear Reaction Compilation and Big Bang Nucleosynthesis  

E-Print Network (OSTI)

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.

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

2001-05-17T23:59:59.000Z

6

Modified big bang nucleosynthesis with non-standard neutron sources  

E-Print Network (OSTI)

During big bang nucleosynthesis, any injection of extra neutrons around the time of the $^7$Be formation, i.e. at a temperature of order $T \\simeq 50$~keV, can reduce the predicted freeze-out amount of $^7$Be + $^7$Li that otherwise remains in sharp contradiction with the Spite plateau value inferred from the observations of Pop II stars. However, the growing confidence in the primordial D/H determinations puts a strong constraint on any such scenario. We address this issue in detail, analyzing different temporal patterns of neutron injection, such as decay, annihilation, resonant annihilation, and oscillation between mirror and standard model world neutrons. For this latter case, we derive the realistic injection pattern taking into account thermal effects (damping and refraction) in the primordial plasma. If the extra neutron supply is the sole non-standard mechanism operating during the BBN, the suppression of lithium abundance below Li/H~$\\leq 1.9 \\times 10^{-10}$ always leads to the overproduction of deuterium, D/H~$\\geq 3.6 \\times 10^{-5}$, well outside the error bars suggested by recent observations.

Alain Coc; Maxim Pospelov; Jean-Philippe Uzan; Elisabeth Vangioni

2014-05-07T23:59:59.000Z

7

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

SciTech Connect

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.

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

8

The X^- Solution to the ^6Li and ^7Li Big Bang Nucleosynthesis Problems  

E-Print Network (OSTI)

The $^6$Li abundance observed in metal poor halo stars appears to exhibit a plateau as a function of metallicity similar to that for $^7$Li, suggesting a big bang origin. However, the inferred primordial abundance of $^6$Li is $\\sim$1000 times larger than that predicted by standard big bang nucleosynthesis for the baryon-to-photon ratio inferred from the WMAP data. Also, the inferred $^7$Li primordial abundance is 3 times smaller than the big bang prediction. We here describe in detail a possible simultaneous solution to both the problems of underproduction of $^6$Li and overproduction of $^7$Li in big bang nucleosynthesis. This solution involves a hypothetical massive, negatively-charged leptonic particle that would bind to the light nuclei produced in big bang nucleosynthesis, but would decay long before it could be detected. We consider only the $X$-nuclear reactions and assume that the effect of decay products is negligible, as would be the case if lifetime were large or the mass difference between the charged particle and its daughter were small. An interesting feature of this paradigm is that, because the particle remains bound to the existing nuclei after the cessation of the usual big bang nuclear reactions, a second longer epoch of nucleosynthesis can occur among $X$-nuclei. We confirm that reactions in which the hypothetical particle is transferred can occur that greatly enhance the production of $^6$Li while depleting $^7$Li. We also identify a new reaction that destroys large amounts of $^7$Be, and hence reduces the ultimate $^7$Li abundance. Thus, big-bang nucleosynthesis in the presence of these hypothetical particles, together with or without an event of stellar processing, can simultaneously solve the two Li abundance problems.

Motohiko Kusakabe; Toshitaka Kajino; Richard N. Boyd; Takashi Yoshida; Grant J. Mathews

2007-11-24T23:59:59.000Z

9

New effects of a long-lived negatively charged massive particle on big bang nucleosynthesis  

SciTech Connect

Primordial {sup 7}Li abundance inferred from observations of metal-poor stars is a factor of about 3 lower than the theoretical value of standard big bang nucleosynthesis (BBN) model. One of the solutions to the Li problem is {sup 7}Be destruction during the BBN epoch caused by a long-lived negatively charged massive particle, X{sup ?}. The particle can bind to nuclei, and X-bound nuclei (X-nuclei) can experience new reactions. The radiative X{sup ?} capture by {sup 7}Be nuclei followed by proton capture of the bound state of {sup 7}Be and X{sup ?} ({sup 7}Be{sub x}) is a possible {sup 7}Be destruction reaction. Since the primordial abundance of {sup 7}Li originates mainly from {sup 7}Li produced via the electron capture of {sup 7}Be after BBN, the {sup 7}Be destruction provides a solution to the {sup 7}Li problem. We suggest a new route of {sup 7}Be{sub x} formation, that is the {sup 7}Be charge exchange at the reaction of {sup 7}Be{sup 3+} ion and X{sup ?}. The formation rate depends on the ionization fraction of {sup 7}Be{sup 3+} ion, the charge exchange cross section of {sup 7}Be{sup 3+}, and the probability that excited states {sup 7}Be{sub x}* produced at the charge exchange are converted to the ground state. We find that this reaction can be equally important as or more important than ordinary radiative recombination of {sup 7}Be and X{sup ?}. The effect of this new route is shown in a nuclear reaction network calculation.

Kusakabe, Motohiko [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); 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 and Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kino, Yasushi [Department of Chemistry, Tohoku University, Sendai 980-8578 (Japan); Mathews, Grant J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)

2014-05-02T23:59:59.000Z

10

Inhomogeneous Big Bang Nucleosynthesis: Upper Limit on Omega_b and Production of Lithium, Beryllium, and Boron  

E-Print Network (OSTI)

We examine the Big Bang nucleosynthesis (BBN) process in the presence of small-scale baryon inhomogeneities. Primordial abundance yields for D, He4, Li6, Li7, Be9, and B11 are computed for wide ranges of parameters characterizing the inhomogeneities taking account of all relevant diffusive and hydrodynamic processes. These calculations may be of interest due to (a) recent observations of the anisotropies in the cosmic microwave background radiation favoring slightly larger baryonic contribution to the critical density, Omega_b, than allowed by a standard BBN scenario and (b) new observational determinations of Li6 and Be9 in metal-poor halo stars. We find considerable parameter space in which production of D and He4 is in agreement with observational constraints even for Omega_b h^2 a factor 2-3 larger than the Omega_b inferred from standard BBN. Nevertheless, in this parameter space synthesis of Li7 in excess of the inferred Li7 abundance on the Spite plateau results. Production of Li6, Be9, and B11 in inhomogeneous BBN scenarios is still typically well below the abundance of these isotopes observed in the most metal-poor stars to date thus neither confirming nor rejecting inhomogeneous BBN. In an appendix we summarize results of a reevaluation of baryon diffusion constants entering inhomogeneous BBN calculations.

K. Jedamzik; Jan B. Rehm

2001-01-17T23:59:59.000Z

11

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

12

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

SciTech Connect

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.

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

13

Inhomogeneous Big Bang Nucleosynthesis Upper Limit on Omega_b and Production of Lithium, Beryllium, and Boron  

E-Print Network (OSTI)

We examine the Big Bang nucleosynthesis (BBN) process in the presence of small-scale baryon inhomogeneities. Primordial abundance yields for D, He4, Li6, Li7, Be9, and B11 are computed for wide ranges of parameters characterizing the inhomogeneities taking account of all relevant diffusive and hydrodynamic processes. These calculations may be of interest due to (a) recent observations of the anisotropies in the cosmic microwave background radiation favoring slightly larger baryonic contribution to the critical density, Omega_b, than allowed by a standard BBN scenario and (b) new observational determinations of Li6 and Be9 in metal-poor halo stars. We find considerable parameter space in which production of D and He4 is in agreement with observational constraints even for Omega_b h^2 a factor 2-3 larger than the Omega_b inferred from standard BBN. Nevertheless, in this parameter space synthesis of Li7 in excess of the inferred Li7 abundance on the Spite plateau results. Production of Li6, Be9, and B11 in inhom...

Jedamzik, K; Rehm, Jan B.

2001-01-01T23:59:59.000Z

14

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

E-Print Network (OSTI)

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...

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

2015-01-01T23:59:59.000Z

15

Big-bang nucleosynthesis with high-energy photon injection  

SciTech Connect

The author discusses the photodissociation of light elements due to the radiative decay of a massive particle, and he has shown how to constrain the model parameters from the observed light-element abundances. He adopted two quasar absorption system (QAS) D/H values, as well as solar system data for D/H and {sup 3}He/H. For each of these, he used two {sup 4}He values. He presents his results in terms of the confidence level at which each theoretical parameter set (i.e., the set of properties of a radiatively decaying particle) is excluded by the observed abundances. His algorithm for computing the confidence level is consistent and general enough to apply not only to the scenarios investigated in this work, but also to many other non-standard theories of BBN.

Holtmann, Erich N.

1999-05-01T23:59:59.000Z

16

General limit on the relation between abundances of D and $^7$Li in big bang nucleosynthesis with nucleon injections  

E-Print Network (OSTI)

The injections of energetic hadrons could have occurred in the early universe by decays of hypothetical long-lived exotic particles. The injections induce the showers of nonthermal hadrons via nuclear scattering. Neutrons generated at these events can react with $^7$Be nuclei and reduce $^7$Be abundance solving a problem of the primordial $^7$Li abundance. We suggest that thermal neutron injection is a way to derive a model independent conservative limit on the relation between abundances of D and $^7$Li in a hadronic energy injection model. We emphasize that an uncertainty in cross sections of inelastic $n+p$ scattering affects the total number of induced neutrons, which determines final abundances of D and $^7$Li. In addition, the annihilations of antinucleons with $^4$He result in higher D abundance and trigger nonthermal $^6$Li production. It is concluded that a reduction of $^7$Li abundance from a value in the standard big bang nucleosynthesis (BBN) model down to an observational two $\\sigma$ upper limit is necessarily accompanied by an undesirable increase of D abundance up to at least an observational 12 $\\sigma$ upper limit from observations of quasi-stellar object absorption line systems. The effects of antinucleons and secondary particles produced in the hadronic showers always lead to a severer constraint. The BBN models involving any injections of extra neutrons are thus unlikely to reproduce a small $^7$Li abundance consistent with observations.

Motohiko Kusakabe; Myung-Ki Cheoun; K. S. Kim

2014-04-11T23:59:59.000Z

17

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

E-Print Network (OSTI)

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.

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

2015-02-13T23:59:59.000Z

18

Deep Mixing of He-3: Reconciling Big Bang and Stellar Nucleosynthesis  

E-Print Network (OSTI)

Low-mass stars, ~1-2 solar masses, near the Main Sequence are efficient at producing He-3, which they mix into the convective envelope on the giant branch and should distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the low observed cosmic abundance of He-3 with the predictions of both stellar and Big Bang nucleosynthesis. In this paper we find, by modeling a red giant with a fully three-dimensional hydrodynamic code and a full nucleosynthetic network, that mixing arises in the supposedly stable and radiative zone between the hydrogen-burning shell and the base of the convective envelope. This mixing is due to Rayleigh-Taylor instability within a zone just above the hydrogen-burning shell, where a nuclear reaction lowers the mean molecular weight slightly. Thus we are able to remove the threat that He-3 production in low-mass stars poses to the Big Bang nucleosynthesis of He-3.

Peter P Eggleton; David S P Dearborn; John C Lattanzio

2006-11-01T23:59:59.000Z

19

After the Big Bang  

NLE Websites -- All DOE Office Websites (Extended Search)

After the Big Bang After the Big Bang Golden Age of Cosmology Big Bang Timeline Big Bang? Standard Big Bang Cosmology Slide 6 Big Bang Nucleosynthesis Redshift and Doppler Shift Doppler Shift Cepheid variables and Nebulae Standard Candles Hubble Expansion Hubble Law Cosmic Microwave Background Cosmic Background Explorer (1989-1993) COBE data/DMR CMB Fluctuations What is inflation? Why believe in inflation? Horizon Problem No inflation With inflation Flatness Problem Slide 24 Wilkinson Microwave Anisotropy Probe (2001-present) Fluctuations and geometry Universe's Baby Pictures Compare to COBE CMB vs. Inflation WMAP angular power spectrum Dark Matter Galaxy Rotation Curves Hot gas in Galaxy Clusters Dark Matter Halo Old view: Density of the Universe determines its destiny Hubble Expansion revisited

20

Big bang nucleosynthesis constraints on hadronically and electromagnetically decaying relic neutral particles  

Science Journals Connector (OSTI)

Big bang nucleosynthesis in the presence of decaying relic neutral particles is examined in detail. All nonthermal processes important for the determination of light-element abundance yields of H2, H3, He3, He4, Li6, and Li7 are coupled to the thermonuclear fusion reactions to obtain comparatively accurate results. Predicted light-element yields are compared to observationally inferred limits on primordial light-element abundances to infer constraints on the abundances and properties of relic decaying particles with decay times in the interval 0.01??sec??X?1012??sec. Decaying particles are typically constrained at early times by He4 or H2, at intermediate times by Li6, and at large times by the He3/H2 ratio. Constraints are shown for a large number of hadronic branching ratios and decaying particle masses and may be applied to constrain the evolution of the early universe.

Karsten Jedamzik

2006-11-08T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Big Bang Darkleosynthesis  

E-Print Network (OSTI)

In a popular class of models, dark matter comprises an asymmetric population of composite particles with short range interactions arising from a confined nonabelian gauge group. We show that coupling this sector to a well-motivated light mediator particle yields efficient darkleosynthesis, a dark-sector version of big-bang nucleosynthesis (BBN), in generic regions of parameter space. Dark matter self-interaction bounds typically require the confinement scale to be above \\Lambda_{QCD}, which generically yields large (>>MeV/dark-nucleon) binding energies. These bounds further suggest the mediator is relatively weakly coupled, so repulsive forces between dark-sector nuclei are much weaker than coulomb repulsion between standard-model nuclei, which results in an exponential barrier-tunneling enhancement over standard BBN. Thus, dark nuclei are easier to make and harder to break than visible species with comparable mass numbers. This process can efficiently yield a dominant population of states with masses significantly greater than the confinement scale and, in contrast to dark matter that is a fundamental particle, may allow the dominant form of dark matter to have high spin > 3/2.

Gordan Krnjaic; Kris Sigurdson

2014-06-04T23:59:59.000Z

22

A Simultaneous Solution to the ^6Li and ^7Li Big Bang Nucleosynthesis Problems from a Long-Lived Negatively-Charged Leptonic Particle  

E-Print Network (OSTI)

The $^6$Li abundance observed in metal poor halo stars exhibits a plateau similar to that for $^7$Li suggesting a primordial origin. However, the observed abundance of $^6$Li is a factor of $10^3$ larger and that of $^7$Li is a factor of 3 lower than the abundances predicted in the standard big bang when the baryon-to-photon ratio is fixed by WMAP. Here we show that both of these abundance anomalies can be explained by the existence of a long-lived massive, negatively-charged leptonic particle during nucleosynthesis. Such particles would capture onto the synthesized nuclei thereby reducing the reaction Coulomb barriers and opening new transfer reaction possibilities, and catalyzing a second round of big bang nucleosynthesis. This novel solution to both of the Li problems can be achieved with or without the additional effects of stellar destruction.

Motohiko Kusakabe; Toshitaka Kajino; Richard N. Boyd; Takashi Yoshida; Grant J. Mathews

2007-11-24T23:59:59.000Z

23

Before the Big Bang  

ScienceCinema (OSTI)

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.

Roger Penrose

2010-09-01T23:59:59.000Z

24

Before the Big Bang  

SciTech Connect

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.

Roger Penrose

2007-02-06T23:59:59.000Z

25

Lithium-6 : Evolution from Big Bang to Present  

E-Print Network (OSTI)

The primordial abundances of Deuterium, he4, and li7 are crucial to determination of the baryon density of the Universe in the framework of standard Big Bang nucleosynthesis (BBN). li6 which is only produced in tiny quantities and it is generally not considered to be a cosmological probe. However, recent major observational advances have produced an estimate of the li6/li7 ratio in a few very old stars in the galactic halo which impacts the question whether or not the lithium isotopes are depleted in the outer layers of halo stars, through proton induced reactions at the base of (or below) the convective zone. li6 is a pure product of spallation through the major production reactions, fast oxygen and alphas interacting on interstellar H, He (especially in the early Galaxy). The rapid nuclei are both synthesized and accelerated by SN II. In this context, the \\li6 evolution should go in step with that of beryllium and boron, recently observed by the Keck and HST telescopes. Li6 adds a new constraint on the early spallation in the Galaxy. In particular, if confirmed, the Li6/Be9 ratio observed in two halo stars (HD 84937, BD +263578) gives strong boundary conditions on the composition and the spectrum of the rapid particles involved. We show that Li6 is essentially intact in halo stars, and a fortiori \\li7. We can define a range of the Li6 abundance in the very early Galaxy consistent with Big Bang nucleosynthesis (5.6 10(-14) to 3. 10(-13) . Following the evolution at increasing metallicity, we explain the abundance in the solar system within a factor of about 2.

Elisabeth Vangioni-Flam; Michel Casse; Roger Cayrel; Jean Audouze; Monique Spite; Francois Spite

1998-11-20T23:59:59.000Z

26

Lithium-6 Evolution from Big Bang to Present  

E-Print Network (OSTI)

The primordial abundances of Deuterium, he4, and li7 are crucial to determination of the baryon density of the Universe in the framework of standard Big Bang nucleosynthesis (BBN). li6 which is only produced in tiny quantities and it is generally not considered to be a cosmological probe. However, recent major observational advances have produced an estimate of the li6/li7 ratio in a few very old stars in the galactic halo which impacts the question whether or not the lithium isotopes are depleted in the outer layers of halo stars, through proton induced reactions at the base of (or below) the convective zone. li6 is a pure product of spallation through the major production reactions, fast oxygen and alphas interacting on interstellar H, He (especially in the early Galaxy). The rapid nuclei are both synthesized and accelerated by SN II. In this context, the \\li6 evolution should go in step with that of beryllium and boron, recently observed by the Keck and HST telescopes. Li6 adds a new constraint on the earl...

Vangioni-Flam, E; Cayrel, R; Audouze, Jean; Spite, M; Spite, F; Vangioni-Flam, Elisabeth; Casse, Michel; Cayrel, Roger; Audouze, Jean; Spite, Monique; Spite, Francois

1998-01-01T23:59:59.000Z

27

Big Bang Synthesis of Nuclear Dark Matter  

E-Print Network (OSTI)

We investigate the physics of dark matter models featuring composite bound states carrying a large conserved dark "nucleon" number. The properties of sufficiently large dark nuclei may obey simple scaling laws, and we find that this scaling can determine the number distribution of nuclei resulting from Big Bang Dark Nucleosynthesis. For plausible models of asymmetric dark matter, dark nuclei of large nucleon number, e.g. > 10^8, may be synthesised, with the number distribution taking one of two characteristic forms. If small-nucleon-number fusions are sufficiently fast, the distribution of dark nuclei takes on a logarithmically-peaked, universal form, independent of many details of the initial conditions and small-number interactions. In the case of a substantial bottleneck to nucleosynthesis for small dark nuclei, we find the surprising result that even larger nuclei, with size >> 10^8, are often finally synthesised, again with a simple number distribution. We briefly discuss the constraints arising from the...

Hardy, Edward; March-Russell, John; West, Stephen M

2014-01-01T23:59:59.000Z

28

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

E-Print Network (OSTI)

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.

David Thomas

1994-12-11T23:59:59.000Z

29

Post Big Bang Processing of the Primordial Elements  

E-Print Network (OSTI)

We explore the Gnedin-Ostriker suggestion that a post-Big-Bang photodissociation process may modify the primordial abundances of the light elements. We consider several specific models and discuss the general features that are necessary (but not necessarily sufficient) to make the model work. We find that with any significant processing, the final D and $^3$He abundances, which are independent of their initial standard big bang nucleosynthesis (SBBN) values, rise quickly to a level several orders of magnitude above the observationally inferred primordial values. Solutions for specific models show that the only initial abundances that can be photoprocessed into agreement with observations are those that undergo virtually no processing and are already in agreement with observation. Thus it is unlikely that this model can work for any non-trivial case unless an artificial density and/or photon distribution is invoked.

M. J. Balbes; R. N. Boyd; G. Steigman; D. Thomas

1995-05-12T23:59:59.000Z

30

From Big Crunch to Big Bang  

E-Print Network (OSTI)

We consider conditions under which a universe contracting towards a big crunch can make a transition to an expanding big bang universe. A promising example is 11-dimensional M-theory in which the eleventh dimension collapses, bounces, and re-expands. At the bounce, the model can reduce to a weakly coupled heterotic string theory and, we conjecture, it may be possible to follow the transition from contraction to expansion. The possibility opens the door to new classes of cosmological models. For example, we discuss how it suggests a major simplification and modification of the recently proposed ekpyrotic scenario.

Justin Khoury; Burt A. Ovrut; Nathan Seiberg; Paul J. Steinhardt; Neil Turok

2001-08-24T23:59:59.000Z

31

BNL | QCD Matter, Big Bang Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

QCD Matter QCD Matter image Physicist Paul Sorensen next to the STAR detector at Brookhaven's Relativistic Heavy Ion Collider Exploring Matter at the Dawn of Time Brookhaven Lab leads the world in exploring how the matter that makes up atomic nuclei behaved just after the Big Bang. At that time, more than 13 billion years ago, there were no protons and neutrons-just a sea of "free" quarks and gluons, fundamental particles whose interactions are governed by nature's strongest force and described by the theory of quantum chromodynamics (QCD). More than 1,000 scientists from around the nation and the world come to Brookhaven to recreate this "quark-gluon plasma" by accelerating heavy ions (atoms stripped of their electrons) to nearly the speed of light and smashing them together at the Lab's

32

Pre-Big Bang, vacuum and noncyclic cosmologies  

E-Print Network (OSTI)

WMAP and Planck open the way to unprecedented Big Bang phenomenology, potentially allowing to test the standard Big Bang model as well as less conventional approaches including noncyclic pre-Big Bang cosmologies that would incorporate a new fundamental scale beyond the Planck scale and, possibly, new ultimate constituents of matter. Alternatives to standard physics can be considered from a cosmological point of view concerning vacuum structure, the nature of space-time, the origin and evolution of our Universe, the validity of quantum field theory and conventional symmetries, solutions to the cosmological constant problem, inflationary scenarios, dark matter and dark energy, the interpretation of string-like theories... Lorentz-like symmetries for the properties of matter (standard or superbradyonic) can then be naturally stable space-time configurations resulting from general cosmological scenarios that incorporate physics beyond the Planck scale and describe the formation and evolution of the present vacuum...

Gonzalez-Mestres, Luis

2012-01-01T23:59:59.000Z

33

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

NLE Websites -- All DOE Office Websites (Extended Search)

John C. Mather, the Big Bang, and the COBE John C. Mather, the Big Bang, and the COBE Resources with Additional Information · Videos John C. Mather Courtesy of NASA "Dr. John C. Mather of NASA's Goddard Space Flight Center has won the 2006 Nobel Prize for Physics, awarded by the Royal Swedish Academy of Sciences. Mather shares the prize with George F. Smoot of the University of California for their collaborative work on understanding the Big Bang. Mather and Smoot analyzed data from NASA's Cosmic Background Explorer (COBE), which studied the pattern of radiation from the first few instants after the universe was formed. In 1992, the COBE team announced that they had mapped the primordial hot and cold spots in the cosmic microwave background radiation. These spots are related to the gravitational field in the early universe, only instants after the Big Bang, and are the seeds for the giant clusters of galaxies that stretch hundreds of millions of light years across the universe. ...

34

Supernova bangs as a tool to study big bang  

SciTech Connect

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.

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

2012-09-15T23:59:59.000Z

35

The hybrid big bang-big crunch method for solving crystal structure from powder diffraction data  

Science Journals Connector (OSTI)

The big bang-big crunch optimization method has been revised, combined with the simulated annealing technique and implemented in the latest version of the EXPO program for solving crystal structure from powder diffraction data.

Altomare, A.

2013-05-15T23:59:59.000Z

36

Big Bang Day : Afternoon Play - Torchwood: Lost Souls  

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

37

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

Office of Scientific and Technical Information (OSTI)

DOE research makes big bang DOE research makes big bang Feature Archive Saul Perlmutter Photo Courtesy of Lawrence Berkeley National Laboratory Saul Perlmutter has been awarded the 2011 Nobel Prize in Physics for his breakthrough research at Lawrence Berkeley National Laboratory. He cofounded the Supernova Cosmology Project (SCP) in 1988, with the breakthrough coming ten years later. The SCP pioneered the methods used to discover the accelerating expansion of the universe through observations of distant supernovae. For many years Perlmutter has been a leader in studies to determine the nature of dark energy. Explore the universe using Science Accelerator; check out the search results for big bang and supernovae. OSTI Homepage Mobile Gallery Subscribe to RSS OSTI Blog Get Widgets Get Alert Services

38

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Supercomputing: A Toolbox to Simulate the Big Bang and Beyond September 19, 2013 - 1:30pm Addthis This image shows the barred spiral galaxy NGC 1398. | Image courtesy of the Dark Energy Survey. This image shows the barred spiral galaxy NGC 1398. | Image courtesy of the Dark Energy Survey. Rob Roser Rob Roser Head, Fermilab Scientific Computing Division What does this project do? A new project sponsored by three of the Energy Department's National Labs will allow scientists to study the evolution of our universe in greater detail with a new cosmological simulation analysis toolbox. This project takes advantage of the Energy Department's investments in supercomputers and specialized high-performance computing

39

What the latest discoveries tell us about the Big Bang, dark matter and multiple universes  

E-Print Network (OSTI)

What the latest discoveries tell us about the Big Bang, dark matter and multiple universes faster' with the application of a small electrical current to the brain for 30 minutes. The promised:LAURENGENTRY Yes, sometimes tDCS provides a cognitive benefit; the data is indisputable. I myself make use

40

Interval type-2 fuzzy PID load frequency controller using Big Bang-Big Crunch optimization  

Science Journals Connector (OSTI)

This paper proposes an optimization based design methodology of interval type-2 fuzzy PID (IT2FPID) controllers for the load frequency control (LFC) problem. Hitherto, numerous fuzzy logic control structures are proposed as a solution of LFC. However, ... Keywords: Big Bang-Big Crunch optimization, Interval type-2 fuzzy PID controllers, Load frequency control

Engin Yesil

2014-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

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

E-Print Network (OSTI)

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

Fygenson, Deborah Kuchnir

42

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

E-Print Network (OSTI)

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

Fygenson, Deborah Kuchnir

43

Before the Big Bang? A Novel Resolution of a Profound Cosmological Puzzle  

SciTech Connect

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.

Penrose, Roger

2007-02-06T23:59:59.000Z

44

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Neutrinos' Instant Identity Changes Could Mean Big Things for the Neutrinos' Instant Identity Changes Could Mean Big Things for the Big Bang Neutrinos' Instant Identity Changes Could Mean Big Things for the Big Bang July 11, 2011 - 12:23pm Addthis Scientists use the near detector to verify the intensity and purity of the muon neutrino beam leaving the Fermilab site. | Courtesy of Fermilab, photo by Peter Ginter Scientists use the near detector to verify the intensity and purity of the muon neutrino beam leaving the Fermilab site. | Courtesy of Fermilab, photo by Peter Ginter Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What are the key facts? Researchers at Fermilab have been studying neutrinos and how they might change, or oscillate, between their three different identities -- electron, muon and tau.

45

Affleck-Dine Baryogenesis and Heavy Element Production from Inhomogeneous Big Bang Nucleosynthesis  

Science Journals Connector (OSTI)

......atomic number greater than 32, because our network includes only those nuclei with Z32, and thus the reaction cannot pro- ceed beyond Germanium, and the nuclei accumulate there. By contrast, the peak at Z=20 should be considered as representing a......

Shunji Matsuura; Alexander D. Dolgov; Shigehiro Nagataki; Katsuhiko Sato

2004-12-01T23:59:59.000Z

46

Positron and gamma-ray signatures of dark matter annihilation and big-bang nucleosynthesis  

SciTech Connect

The positron excess observed by the PAMELA experiment may come from dark matter annihilation, if the annihilation cross section is large enough. We show that the dark matter annihilation scenarios to explain the positron excess may also be compatible with the discrepancy of the cosmic lithium abundances between theory and observations. The winolike neutralino in the supersymmetric standard model is a good example for it. This scenario may be confirmed by Fermi satellite experiments.

Hisano, Junji; Kawasaki, Masahiro [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8568 (Japan); Kohri, Kazunori [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Nakayama, Kazunori [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)

2009-03-15T23:59:59.000Z

47

The Ekpyrotic Universe: Colliding Branes and the Origin of the Hot Big Bang  

E-Print Network (OSTI)

We propose a cosmological scenario in which the hot big bang universe is produced by the collision of a brane in the bulk space with a bounding orbifold plane, beginning from an otherwise cold, vacuous, static universe. The model addresses the cosmological horizon, flatness and monopole problems and generates a nearly scale-invariant spectrum of density perturbations without invoking superluminal expansion (inflation). The scenario relies, instead, on physical phenomena that arise naturally in theories based on extra dimensions and branes. As an example, we present our scenario predominantly within the context of heterotic M-theory. A prediction that distinguishes this scenario from standard inflationary cosmology is a strongly blue gravitational wave spectrum, which has consequences for microwave background polarization experiments and gravitational wave detectors.

Justin Khoury; Burt A. Ovrut; Paul J. Steinhardt; Neil Turok

2001-03-29T23:59:59.000Z

48

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

ScienceCinema (OSTI)

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.

Smoot, George

2011-04-28T23:59:59.000Z

49

Are Dark Matter and Dark Energy the Residue of the Expansion-Reaction to the Big Bang ?  

E-Print Network (OSTI)

We derive the phenomenological Milgrom square-law acceleration, describing the apparent behavior of dark matter, as the reaction to the Big Bang from a model based on the Lorentz-Dirac equation of motion traditionally describing radiation reaction in electromagnetism but proven applicable to expansion reaction in cosmology. The model is applied within the Robertson-Walker hypersphere, and suggests that the Hubble expansion exactly cancels the classical reaction imparted to matter following the Big Bang, leaving behind a residue proportional to the square of the acceleration. The model further suggests that the energy density associated with the reaction acceleration is precisely the critical density for flattening the universe thus providing a potential explanation of dark energy as well. A test of this model is proposed.

Harry I. Ringermacher; Lawrence R. Mead

2006-10-16T23:59:59.000Z

50

"Big Bang" as a first-order phase transition in the early Universe  

E-Print Network (OSTI)

It is argued that the "Big Bang" initiating the creation of our Universe may be a consequence of a first-order phase transition induced by interaction of a fundamental non-linear scalar field with gravitational field. The Lagrangian describing the scalar field f characterized by "imaginary mass" and nonlinearity of ${\\phi}^4$ type, existing in the space-time with non-zero scalar curvature $R$, is proposed to be augmented with an additional linear term $\\propto R{\\phi}$, along with the standard term $\\propto R|{\\phi}|^2$ quadratic in ${\\phi}$. The term linear in ${\\phi}$, playing the role of an "external field", leads to a cubic equation in ${\\phi}$ for the extrema of the potential energy of the scalar field and ensures the possibility of a first-order phase transition driven by the parameter proportional to $R$. It is assumed that the early Universe is filled with non-linear scalar field in the ground state and cold matter, neutral with respect to all charges, satisfying the equation of state $p={\

E. A. Pashitskii

2014-05-23T23:59:59.000Z

51

HD 140283: A STAR IN THE SOLAR NEIGHBORHOOD THAT FORMED SHORTLY AFTER THE BIG BANG  

SciTech Connect

HD 140283 is an extremely metal-deficient and high-velocity subgiant in the solar neighborhood, having a location in the Hertzsprung-Russell diagram where absolute magnitude is most sensitive to stellar age. Because it is bright, nearby, unreddened, and has a well-determined chemical composition, this star avoids most of the issues involved in age determinations for globular clusters. Using the Fine Guidance Sensors on the Hubble Space Telescope, we have measured a trigonometric parallax of 17.15 {+-} 0.14 mas for HD 140283, with an error one-fifth of that determined by the Hipparcos mission. Employing modern theoretical isochrones, which include effects of helium diffusion, revised nuclear reaction rates, and enhanced oxygen abundance, we use the precise distance to infer an age of 14.46 {+-} 0.31 Gyr. The quoted error includes only the uncertainty in the parallax, and is for adopted surface oxygen and iron abundances of [O/H] = -1.67 and [Fe/H] = -2.40. Uncertainties in the stellar parameters and chemical composition, especially the oxygen content, now contribute more to the error budget for the age of HD 140283 than does its distance, increasing the total uncertainty to about {+-}0.8 Gyr. Within the errors, the age of HD 140283 does not conflict with the age of the Universe, 13.77 {+-} 0.06 Gyr, based on the microwave background and Hubble constant, but it must have formed soon after the big bang.

Bond, Howard E.; Nelan, Edmund P. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); VandenBerg, Don A. [Department of Physics and Astronomy, University of Victoria, P.O. Box 3055, Victoria, BC V8W 3P6 (Canada); Schaefer, Gail H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Harmer, Dianne, E-mail: bond@stsci.edu, E-mail: nelan@stsci.edu, E-mail: vandenbe@uvic.ca, E-mail: schaefer@chara-array.org, E-mail: diharmer@noao.edu [National Optical Astronomy Observatories, 950 North Cherry Avenue, Tucson, AZ 85726 (United States)

2013-03-01T23:59:59.000Z

52

SciTech Connect: Quark mass variation constraints from Big Bang...  

Office of Scientific and Technical Information (OSTI)

NUCLEAR PHYSICS; NUCLEOSYNTHESIS; QUANTUM CHROMODYNAMICS; QUARKS; REACTION KINETICS Word Cloud More Like This Full Text preview image File size NAView Full Text View Full Text...

53

On Synthesis of the Big Bang Model with Freundlich's Redshift and its Cosmological Consequences  

E-Print Network (OSTI)

We derive exact theoretical value of the constant cosmic background radiation (CBR) temperature $T_0$ using the interconnections between the Gamow, Alpher and Herman (GAH) hot Big Bang cosmology model of the expanding Universe and the modified Freundlich redshift. As a result of this confluence an astonishing relationship between $T_0$ and the four fundamental physical constants $c$,$\\hbar$,$k$,$G$ is found including also the Melvin's value of the Freundlich constant $A_s$.Then the resulting predicted the CBR temperature is $T_0=2.76626 K$. This prediction show excellent agreement with the data obtained from ground-based and balloon-borne observations and also with a mean of the perfect black-body spectrum CMB temperature $2.725 K$ measured COBE in 1992. Using a new cosmological model we determine the horizon scale, age and mass of the present observable Universe. The calculations based on discrete redshift equations for the electromagnetic, electroweak phases and Planck epoch of the Universe predicts a graviton and string masses, which are originated beyond on Planck time. The predicted graviton mass $m_Gr$ is about five orders of magnitude less than the present "the best possible upper bounds on the mass of the graviton", which may be "discovered" in the proposed LISA observations. We present quantitative new results for the different quantum-cosmological parameters. Finally, it is showed that the mystery largeness and smallness dimensionless combination of the Quantum Cosmological constant $\\Lambda_0$ and Planck length $l_Pl$ may be derived as their ratio from the Trans-Planck redshift relation. Thus is found the meaning a famous largeness cosmological number $c^3/\\hbarG\\Lambda_0=2.8*10^{125}$ that is inverse of $\\Lambda_0 l_Pl^2=3.6*10^{-126}$, and "which in 1930s was a regarded as a major problem by Eddington and Dirac".

Asger G. Gasanalizade

2010-09-24T23:59:59.000Z

54

Origin of matter and space-time in the big bang  

SciTech Connect

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.

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

55

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

E-Print Network (OSTI)

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.

Jin He

2005-12-26T23:59:59.000Z

56

Phase transitions in the early and the present Universe: from the big bang to heavy ion collisions  

E-Print Network (OSTI)

In these lectures I discuss cosmological phase transitions with the goal of establishing the possibility of observational consequences. I argue that the {\\em only} phase transition amenable of experimental study within the foreseeable future is that predicted by QCD and discuss some of the potential observational cosmological consequences associated with this phase transition(s). I describe the experimental effort to study the QCD phase transition(s) at RHIC and SPS and summarize some of the recent experimental results. The possibility of novel phases of QCD in the core of pulsars is discussed along with the suggested observational consequences. A brief review of standard big bang cosmology as well as the astrophysics of compact stars sets the stage for understanding the observational cosmological and astrophysical consequences of phase transitions in the standard model.

D. Boyanovsky

2001-02-09T23:59:59.000Z

57

A Relativistic-Proton Dark Matter Would Be Evidence The Big Bang Probably Satisfied The Second Law Of Thermodynamics  

E-Print Network (OSTI)

A new research hypothesis has been developed by the author based upon finding astronomically based `cosmic constituents` of the Universe that may be created or influenced by or have a special relationship with possible dark matter candidates. He then developed a list of 14 relevant and plausible `cosmic constituents` of the Universe, which then was used to establish a list of constraints regarding the nature and characteristics of the long-sought dark matter particles. A dark matter candidate was then found that best conformed to the 14 constraints established by the `cosmic constituents.` The author then used this same dark matter candidate to provide evidence that the Big Bang was relativistic, had a low entropy, and therefore probably satisfied the Second Law of Thermodynamics.

Jerome Drexler

2007-02-15T23:59:59.000Z

58

Geometrical Effects of Baryon Density Inhomogeneities on Primordial Nucleosynthesis  

E-Print Network (OSTI)

We discuss effects of fluctuation geometry on primordial nucleosynthesis. For the first time we consider condensed cylinder and cylindrical-shell fluctuation geometries in addition to condensed spheres and spherical shells. We find that a cylindrical shell geometry allows for an appreciably higher baryonic contribution to be the closure density ($\\Omega_b h_{50}^2 \\la 0.2$) than that allowed in spherical inhomogeneous or standard homogeneous big bang models. This result, which is contrary to some other recent studies, is due to both geometry and recently revised estimates of the uncertainties in the observationally inferred primordial light-element abundances. We also find that inhomogeneous primordial nucleosynthesis in the cylindrical shell geometry can lead to significant Be and B production. In particular, a primordial beryllium abundance as high as [Be] = 12 + log(Be/H) $\\approx -3$ is possible while still satisfying all of the light-element abundance constraints.

M. Orito; T. Kajino; R N. Boyd; G J. Mathews

1996-09-19T23:59:59.000Z

59

Big Bang Day : Today  

ScienceCinema (OSTI)

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 )

None

2011-04-25T23:59:59.000Z

60

Neutron injection during primordial nucleosynthesis alleviates the primordial 7Li problem  

E-Print Network (OSTI)

We present a parametrized study of the effects of free thermal neutron injection on primordial nucleosynthesis, where both the rate and the time scale of injection are varied. This generic approach is found to yield a successful solution for reducing the 7Li abundance without causing significant problems to other elemental abundances. Our analysis demonstrates that hadronic injection, possibly due to decays or annihilations of dark matter particles with a mass of about 1 to 30 GeV, provides a possible solution to an outstanding problem in the standard Big Bang model.

Daniel Albornoz Vasquez; Alexander Belikov; Alain Coc; Joseph Silk; Elisabeth Vangioni

2012-08-02T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Probing neutrino physics with a self-consistent treatment of the weak decoupling, nucleosynthesis, and photon decoupling epochs  

E-Print Network (OSTI)

We show that a self-consistent and coupled treatment of the weak decoupling, big bang nucleosynthesis, and photon decoupling epochs can be used to provide new insights and constraints on neutrino sector physics from high-precision measurements of light element abundances and cosmic microwave background observables. Implications of beyond-standard-model physics in cosmology, especially within the neutrino sector, are assessed by comparing predictions against five observables: the baryon energy density, helium abundance, deuterium abundance, effective number of neutrinos, and sum of the light neutrino mass eigenstates. We give examples for constraints on dark radiation, neutrino rest mass, lepton numbers, and scenarios for light and heavy sterile neutrinos.

Grohs, E; Kishimoto, C T; Paris, M W

2015-01-01T23:59:59.000Z

62

Electromagnetic cascades and cascade nucleosynthesis in the early Universe  

Science Journals Connector (OSTI)

We describe a calculation of electromagnetic cascading in radiation and matter in the early Universe initiated by the decay of massive particles or by some other process. We have used a combination of Monte Carlo and numerical techniques which enables us to use exact cross sections, where known, for all the relevant processes. In cascades initiated after the epoch of big bang nucleosynthesis ? rays in the cascades will photodisintegrate He4, producing He3 and deuterium. Using the observed He3 and deuterium abundances we are able to place constraints on the cascade energy deposition as a function of cosmic time. In the case of the decay of massive primordial particles we place limits on the density of massive primordial particles as a function of their mean decay time, and on the expected intensity of decay neutrinos.

R. J. Protheroe; T. Stanev; V. S. Berezinsky

1995-04-15T23:59:59.000Z

63

Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations  

E-Print Network (OSTI)

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.

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

2014-09-19T23:59:59.000Z

64

Big Bang Day : Physics Rocks  

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

65

Big Bang Day: Engineering Solutions  

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

66

Relating gravitational wave constraints from primordial nucleosynthesis, pulsar timing, laser interferometers, and the CMB: Implications for the early universe  

Science Journals Connector (OSTI)

We derive a general equation relating the gravitational-wave observables r and ?0gw(f); or the observables ?0gw(f1) and ?0gw(f2). Here, r is the so-called “tensor-to-scalar ratio,” which is constrained by cosmic-microwave-background experiments; and ?0gw(f) is the energy spectrum of primordial gravitational waves, which is constrained, e.g., by pulsar-timing measurements, laser-interferometer experiments, and the standard big bang nucleosynthesis bound. Differentiating this equation yields a new expression for the tilt dln??0gw(f)/dln?f of the present-day gravitational-wave spectrum. The relationship between r and ?0gw(f) depends sensitively on the uncertain physics of the early universe, and we show that this uncertainty may be encapsulated (in a model-independent way) by two quantities: w^(f) and n^t(f), where n^t(f) is a certain logarithmic average over nt(k) (the primordial tensor spectral index); and w^(f) is a certain logarithmic average over w˜(a) (the effective equation-of-state parameter in the early universe, after horizon re-entry). Here, the effective equation-of-state parameter w˜(a) is a combination of the ordinary equation-of-state parameter w(a) and the bulk viscosity ?(a). Thus, by comparing observational constraints on r and ?0gw(f), one obtains (remarkably tight) constraints in the {w^(f),n^t(f)} plane. In particular, this is the best way to constrain (or detect) the presence of a stiff energy component (with w>1/3) in the early universe, prior to big bang nucleosynthesis. (The discovery of such a component would be no more surprising than the discovery of a tiny cosmological constant at late times!) Finally, although most of our analysis does not assume inflation, we point out that if cosmic-microwave-background experiments detect a nonzero value for r, then we will immediately obtain (as a free by-product) a new upper bound w^?0.55 on the logarithmically averaged effective equation-of-state parameter during the “primordial dark age” between the end of inflation and the start of big bang nucleosynthesis.

Latham A. Boyle and Alessandra Buonanno

2008-08-18T23:59:59.000Z

67

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

7 7 by B.D. Fields (Univ. of Illinois) and S. Sarkar (Univ. of Oxford). Big-bang nucleosynthesis (BBN) offers the deepest reliable probe of the early universe, being based on well-understood Standard Model physics [1-4]. Predictions of the abundances of the light elements, D, 3 He, 4 He, and 7 Li, synthesized at the end of the "first three minutes," are in good overall agreement with the primordial abundances inferred from observational data, thus validating the standard hot big-bang cosmology (see [5] for a review). This is particularly impressive given that these abundances span nine orders of magnitude - from 4 He/H ∼ 0.08 down to 7 Li/H ∼ 10 -10 (ratios by number). Thus BBN provides powerful constraints on possible deviations from the standard cosmology [2], and on new physics beyond the Standard Model [3]. 20.1. Theory The synthesis of the light elements is sensitive

68

Gravitational-wave stochastic background from kinks and cusps on cosmic strings  

Science Journals Connector (OSTI)

We compute the contribution of kinks on cosmic string loops to stochastic background of gravitational waves (SBGW). We find that kinks contribute at the same order as cusps to the SBGW. We discuss the accessibility of the total background due to kinks as well as cusps to current and planned gravitational-wave detectors, as well as to the big bang nucleosynthesis (BBN), the cosmic microwave background (CMB), and pulsar timing constraints. As in the case of cusps, we find that current data from interferometric gravitational-wave detectors, such as LIGO, are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds.

S. Ölmez; V. Mandic; X. Siemens

2010-05-13T23:59:59.000Z

69

Gravitational-Wave Stochastic Background from Cosmic Strings  

Science Journals Connector (OSTI)

We consider the stochastic background of gravitational waves produced by a network of cosmic strings and assess their accessibility to current and planned gravitational wave detectors, as well as to big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and pulsar timing constraints. We find that current data from interferometric gravitational wave detectors, such as Laser Interferometer Gravitational Wave Observatory (LIGO), are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds. Future more sensitive LIGO runs and interferometers such as Advanced LIGO and Laser Interferometer Space Antenna (LISA) will be able to explore substantial parts of the parameter space.

Xavier Siemens; Vuk Mandic; Jolien Creighton

2007-03-13T23:59:59.000Z

70

Big Bang riddles and their revelations  

Science Journals Connector (OSTI)

...even thinner, tightrope to walk on. 4. God on amphetamine In the end, history flushed...spectacular predic- tions leading to modern particle physics. Good examples are the discovery of new particles and antiparticles, the electroweak theory...

1999-01-01T23:59:59.000Z

71

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

E-Print Network (OSTI)

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.

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

2014-12-22T23:59:59.000Z

72

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

E-Print Network (OSTI)

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 thermonucl...

He, J J; Parikh, A; Kahl, D; Bertulani, C A

2014-01-01T23:59:59.000Z

73

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

E-Print Network (OSTI)

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.

Vivian Poulin; Pasquale D. Serpico

2015-02-04T23:59:59.000Z

74

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

E-Print Network (OSTI)

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.

Poulin, Vivian

2015-01-01T23:59:59.000Z

75

Bose and Fermi gases in the early Universe with self-gravitational effect  

SciTech Connect

We study the self-gravitational effect on the equation of state (EoS) of Bose and Fermi gases in thermal equilibrium at the end of reheating, the period after quark-hadron transition and before big bang nucleosynthesis (BBN). After introducing new grand canonical partition functions based on the work of Uhlenbeck and Gropper, we notice some interesting features of the newly developed EoSs with distinct behaviors of relativistic and nonrelativistic gases under self-gravity. The usual negligence of the self-gravitational effect when solving the background expansion of the early Universe is justified with numerical results, showing the magnitude of the self-gravitational modification of the state constant to be less than O(10{sup -78}). This helps us to clarify the background thermal evolution of the primordial patch. Such clarification is crucial in testing gravity theories, evaluating inflation models and determining element abundances in BBN.

Niu Yuezhen; Huang Junwu; Ma Boqiang [School of Physics and State Keye Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China) and Center for High Energy Physics, Peking University, Beijing 100871 (China) and Center for History and Philosophy of Science, Peking University, Beijing 100871 (China)

2011-03-15T23:59:59.000Z

76

bigbangnucrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

August August 2011 by B.D. Fields (Univ. of Illinois) and S. Sarkar (Univ. of Oxford). Big-Bang nucleosynthesis (BBN) offers the deepest reliable probe of the early Universe, being based on well-understood Standard Model physics [1-8]. Predictions of the abundances of the light elements, D, 3 He, 4 He, and 7 Li, synthesized at the end of the 'first three minutes', are in good overall agreement with the primordial abundances inferred from observational data, thus validating the standard hot Big-Bang cosmology (see [9] for a review). This is particularly impressive given that these abundances span nine orders of magnitude - from 4 He/H ∼ 0.08 down to 7 Li/H ∼ 10 -10 (ratios by number). Thus BBN provides powerful constraints on possible deviations from the standard cosmology, and on new physics beyond the Standard Model [4-7]. 22.1. Theory The synthesis of the light elements is sensitive

77

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

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

78

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

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

79

Big Bang Day: 5 Particles - 1. The Electron  

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

80

Big Bang Day: 5 Particles - 4. The Neutrino  

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Small-buck change yields big-bang gain  

SciTech Connect

A cost-effective way to reduce CO{sub 2} from operating coal-fired power plants is to improve combustion efficiency or, in other words, reduce heat rate. Stabilizing firing rate, furnace draft and air flow can improve the heat rate by 1 or 2% in most units. The 75 MW Unit 3 and 109 MW Unit 4 of Kentucky Utilities' Green River Generation Station had difficulty maintaining combustion control operations. To improve this, the strategy was adopted similar to that used at the sister unit Tyrone 3 developed for firing rate/throttle pressure stability to ensure that the boiler control remained on automatic at all times. The system logic transfers control of the furnace draft to the units' induced draft (ID) fans. The modifications improved temperature and pressure control as well as unit response while opacity excursion, NOx emission and heat rate decreased by 3% in Unit 3 and 5.4% in Unit 4. 1 photo.

Ferrer, A.; Keller, G. [Burns and Roe (United States)

2007-07-15T23:59:59.000Z

82

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

ScienceCinema (OSTI)

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

None

2011-04-25T23:59:59.000Z

83

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

ScienceCinema (OSTI)

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 .......

None

2011-04-25T23:59:59.000Z

84

Measuring Spacetime: From the Big Bang to Black Holes  

Science Journals Connector (OSTI)

...ekpyrotic model inspired by string theory and a related eternally oscillating model have attracted...as a finite guitar string has a...ekpyrotic model inspired by string theory and a related eternally oscillating model have attracted...

Max Tegmark

2002-05-24T23:59:59.000Z

85

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

NLE Websites -- All DOE Office Websites (Extended Search)

do you interrogate something so elusive that it could zip through a barrier of iron a light-year thick as if it were empty space? At the U.S. Department of Energy's Princeton...

86

GeV scale metastable particles and BBN Unintended benefit of metastable  

E-Print Network (OSTI)

particular can explain PAMELA and FGST excess of lepton cosmic rays, Arkani-Hamed et al. 2008, MP and Ritz;5 Status of standard BBN with CMB input Coc et al, ApJ 2005 "Lithium problem"!! #12;6 9Be vs metallicity burned by protons. 4He, 3He, D, p, and n can be all considered as an input for lithium calculation. 1. 3

Weaver, Harold A. "Hal"

87

Resonant high energy graviton to photon conversion at post recombination epoch  

E-Print Network (OSTI)

Resonant conversion of high energy gravitons into photons in large scale cosmological magnetic fields at the post recombination epoch is considered. It is shown that the probability of the resonance photon production is much higher than the non-resonant one. As a result an observable isotropic background of cosmic gamma rays might be created. As shown in our previous paper, an early population of primordial black holes (PBHs) prior to big bang nucleosynthesis (BBN) could be an efficient source of high frequency gravitational waves. For the primordial black hole mass about $10^8$ g the produced photons would be the dominant component of the soft to hard Cosmic X-ray Background (CXB) and for lower masses the spectrum is shifted down to the ultraviolet and optic.

Alexander D. Dolgov; Damian Ejlli

2013-03-06T23:59:59.000Z

88

Beryllium abundances in metal-poor stars  

Science Journals Connector (OSTI)

......standard big bang nucleosynthesis. Be cannot be produced by nuclear fusion in the interiors of stars; in contrast, Be would be...model of Allen Santillan (1991) for our sample stars. Input parameters, such as radial velocities, parallaxes and......

K. F. Tan; J. R. Shi; G. Zhao

2009-01-01T23:59:59.000Z

89

Outstanding problems in nuclear astrophysics: recent progress at TRIUMF  

SciTech Connect

Recent experimental and theoretical efforts at TRIUMF on nuclear reactions relevant to big bang nucleosynthesis, quiescent stellar fusion, classical novae, and Type I X-ray bursts are described.

Davids, B., E-mail: davids@triumf.ca [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC (Canada)

2014-04-15T23:59:59.000Z

90

Nucleosynthesis in Early Neutrino Driven Winds  

SciTech Connect

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.

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

2008-01-09T23:59:59.000Z

91

Nucleosynthesis in Early Neutrino Driven Winds  

SciTech Connect

Two recent issues realted 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.

Hoffman, R. D.; Fisker, J. L. [Lawrence Livermore National Laboratory, PO Box 808, L-414, Livermore, CA 94550 (United States); Pruet, J. [Lawrence Livermore National Laboratory, PO Box 808, L-059, Livermore, CA 94550 (United States); Woosley, S. E. [Department of Astronomy and Astrophysics, UC Santa Cruz, Santa Cruz, CA 95064 (United States); Janka, H.-T.; Buras, R. [Max Plank Institute for Astrophysics, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany)

2008-04-17T23:59:59.000Z

92

Nucleosynthesis in O-Ne-Mg Supernovae  

SciTech Connect

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.

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

2007-12-18T23:59:59.000Z

93

NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS  

E-Print Network (OSTI)

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

Rauscher, Thomas

94

RFID-based solution for galleries and museums visit modelling using Markov model, BBN's and MAP decisions  

Science Journals Connector (OSTI)

RFID technologies are becoming increasingly popular and widely used in many applications. Tags can be used for environment and habit monitoring, healthcare applications, home automation and pedestrian or vehicle traffic control. This paper describes the method of building a robust N-state Markov model that describes visitor's behaviour in a gallery room. The built model can be used in planning of exhibitions, in modelling of visitor's preferences, and/or in generation of predictions related with exhibition lasting, expected sales and pricing. Presented system performance improvements are realised through Bayesian belief network (BBN) and maximum a posterior probability (MAP) decision approximation algorithm.

Petar Solic; Nikola Rozic; Josko Radic

2010-01-01T23:59:59.000Z

95

Congeniality bounds on quark masses from nucleosynthesis  

Science Journals Connector (OSTI)

The work of Jaffe, Jenkins and Kimchi [Phys. Rev. D 79, 065014 (2009)] is revisited to see if indeed the region of congeniality found in their analysis survives further restrictions from nucleosynthesis. It is observed that much of their congenial region disappears when imposing conditions required to produce the correct and required abundances of the primordial elements as well as ensure that stars can continue to burn hydrogen nuclei to form helium as the first step in forming heavier elements in stellar nucleosynthesis. The remaining region is a very narrow slit reduced in width from around 29 MeV found by Jaffe et al. to only about 2.2 MeV in the difference of the nucleon/quark masses. Further bounds on ?mq/mq seem to reduce even this narrow slit to the physical point itself.

M. Hossain Ali; M. Jakir Hossain; Abdullah Shams Bin Tariq

2013-08-02T23:59:59.000Z

96

Modeling The Nucleosynthesis Of Massive Stars  

E-Print Network (OSTI)

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.

T. Rauscher

2003-09-09T23:59:59.000Z

97

Supernova neutrinos, giant resonances, and nucleosynthesis  

SciTech Connect

Almost all of the 3{center dot}10{sup 53} ergs liberated in a core collapse supernova is radiated as neutrinos by the cooling neutron star. The neutrinos can excite nuclei in the mantle of the star by their neutral and charged current reactions. I argue that the resulting spallation reactions are an important nucleosynthesis mechanism that may be responsible for the galactic abundances of {sup 7}Li, {sup 11}B, {sup 19}F, {sup 138}La, {sup 180}Ta, and approximately a dozen other light nuclei. 18 refs., 1 fig., 1 tab.

Haxton, W.

1990-01-01T23:59:59.000Z

98

New Bounds for Axions and Axion-Like Particles with keV-GeV Masses  

E-Print Network (OSTI)

We give updated constraints on hypothetical light bosons with a two-photon coupling such as axions or axion-like particles (ALPs). We focus on masses and lifetimes where decays happen near big bang nucleosynthesis (BBN), thus altering the baryon-to-photon ratio and number of relativistic degrees of freedom between the BBN epoch and the cosmic microwave background (CMB) last scattering epoch, in particular such that $N_{\\rm eff}^{\\rm CMB} 3\\sigma$ by the combination of CMB+D/H measurements if only ALPs and three thermalized neutrino species contribute to $N_{\\rm eff}$. The bound relaxes if there are additional light degrees of freedom present which, in this scenario, have their contribution limited to $\\Delta N_{\\rm eff}=1.1\\pm0.3$. We give forecasts showing that a number of experiments are expected to reach the sensitivity needed to further test this region, such as Stage-IV CMB and SUPER-KEKB, the latter a direct test insensitive to any extra degrees of freedom.

Millea, Marius; Fields, Brian

2015-01-01T23:59:59.000Z

99

Effect of Uncertainties in Nuclear Reaction Rate on Nucleosynthesis Paths  

Science Journals Connector (OSTI)

......of Theoretical Physics, Vol. 123, No...Nuclear Reaction Rate on Nucleosynthesis...Nuclear Astro- physics Compilation of Reaction Rates (NACRE),2...synthesis paths pass through 20Ne or...18O reaction rate is larger than......

Kazuyuki Yamamoto; Kiyoshi Kato; Takahiro Wada; Masahisa Ohta

2010-06-01T23:59:59.000Z

100

space. Theories of how the Universe evolved in the first few moments after the Big Bang  

E-Print Network (OSTI)

both books are efforts to `explain' chemistry, they have different scopes and styles. Both succeed. Stimulating Concepts in Chemistry is exclusively focused on organic chemistry and its borders with the philosophy of its subjects--morewiththeirnutsandbolts. Organic chemistry is currently in a phase of change

Prentiss, Mara

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Pre-big bang collapsing universe from modern Kaluza-Klein theory of gravity  

E-Print Network (OSTI)

We study the collapse of the universe described by a scalar field spherically symmetric collapse of a system described by a massless scalar field from a 5D Riemann-flat canonical metric, on which we make a dynamical foliation on the extra space-like dimension. The asymptotic universe (absent of singularities) results to be finite in size and energy density, with an vacuum dominated equation of state. The important result here obtained is that the asymptotic back-reaction effects are given by a negative constant: $.\\frac{3}{2 \\Lambda_0 \\psi^2} +{1\\over 2a^2} |_{t\\rightarrow\\infty} = {-8 \\Lambda_0 \\over 3 \\pi G}$.

Bellini, Mauricio

2011-01-01T23:59:59.000Z

102

Environmental/economic power dispatch using a Hybrid Big Bang–Big Crunch optimization algorithm  

Science Journals Connector (OSTI)

The combined economic and emission dispatch (CEED) problem where objective function is highly non ... –BC) optimization algorithm technique for solving the CEED. Six generator test and IEEE 30 standard...

Yacine Labbi; Djilani Ben Attous

2013-12-01T23:59:59.000Z

103

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

E-Print Network (OSTI)

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.

V. E. Kuzmichev; V. V. Kuzmichev

2008-04-30T23:59:59.000Z

104

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

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

105

Reaching Back Towards the Big Bang | U.S. DOE Office of Science...  

Office of Science (SC) Website

the collision of lead nuclei at 5.5 TeV per nucleon pair. This is 30 times the collision energy of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven, the only operating...

106

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

E-Print Network (OSTI)

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.

Serge F. Timashev

2008-04-17T23:59:59.000Z

107

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

E-Print Network (OSTI)

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 ma...

Kuzmichev, V E

2007-01-01T23:59:59.000Z

108

Radiochemical investigations of 177Lu-DOTA-8-Aoc-BBN[7-14]NH2: an in vitro/in vivo assessment of the targeting ability of this new radiopharmaceutical for PC-3 human prostate cancer cells  

Science Journals Connector (OSTI)

Bombesin (BBN), a 14 amino acid peptide, is an analogue of human gastrin releasing peptide (GRP) that binds to GRP receptors (GRPr) with high affinity and specificity. The \\{GRPr\\} is over expressed on a variety of human cancer cells including prostate, breast, lung, and pancreatic cancers. The specific aim of this study was to identify a BBN analogue that can be radiolabeled with 177Lu and maintains high specificity for \\{GRPr\\} positive prostate cancer tumors in vivo. A preselected synthetic sequence via solid phase peptide synthesis (SPPS) was designed to produce a DOTA-BBN (DOTA = 1,4,7,10-tetraazacyclododecane-N,N?,N??,N???-tetraacetic acid) conjugate with the following general structure: DOTA-X-Q-W-A-V-G-H-L-M-(NH2), where the spacer group, X = ?-NH2(CH2)7COOH (8-Aoc). The BBN-construct was purified by reversed phase-HPLC (RP-HPLC). Electrospray Mass Spectrometry (ES-MS) was used to characterize both metallated and non-metallated BBN-conjugates. The new DOTA-conjugate was metallated with 177Lu(III)Cl3 or non-radioactive Lu(III)Cl3. The 177Lu(III)- and non-radiolabeled Lu(III)-conjugates exhibit the same retention times under identical RP-HPLC conditions. The 177Lu-DOTA-8-Aoc-BBN[7-14]NH2 conjugate was found to exhibit optimal pharmacokinetic properties in CF-1 normal mice. In vitro and in vivo models demonstrated the ability of the 177Lu-DOTA-8-Aoc-BBN[7-14]NH2 conjugate to specifically target GRP receptors expressed on PC-3 human prostate cancer cells.

C.Jeffrey Smith; Hariprasad Gali; Gary L. Sieckman; Donald L. Hayes; Nellie K. Owen; Dana G. Mazuru; Wynn A. Volkert; Timothy J. Hoffman

2003-01-01T23:59:59.000Z

109

Effects of Long-lived 10 MeV Scale Sterile Neutrino on Primordial Elemental Abundances and Effective Neutrino Number  

E-Print Network (OSTI)

The primordial lithium abundance inferred from observations of metal-poor stars is ~3 times smaller than the theoretical value in standard big bang nucleosynthesis (BBN) model. We assume a simple model including a sterile neutrino nu_H with mass of O(10) MeV which decays long after BBN. We then investigate cosmological effects of a sterile neutrino decay. We formulate the injection spectrum of nonthermal photons induced by electrons and positrons generated at the nu_H decay, as a function of the nu_H mass and the photon temperature. We then consistently solve (1) the cosmic thermal history, (2) nonthermal nucleosynthesis induced by the nonthermal photons, (3) the baryon-to-photon ratio eta, and (4) the effective neutrino number N_eff. Amounts of energy injection at the nu_H decay are constrained from limits on primordial D and 7Li abundances, the N_eff value, and the cosmic microwave background energy spectrum. We find that 7Be is photodisintegrated and the Li problem is partially solved for the lifetime 10^4-10^5 s and the mass >~ 14 MeV. 7Be destruction by more than a factor of 3 is not possible because of an associated D over-destruction. In the parameter region, the eta value is decreased slightly, while the N_eff value is increased by a factor of <~ 1. In this study, errors in photodisintegration cross sections of 7Be(g, a)3He and 7Li(g, a)3H that have propagated through literatures are corrected. It is then found that the new photodisintegration rates are 2.3 to 2.5 times smaller than the old rates, so that efficiencies of 7Be and 7Li photodisintegration are significantly smaller.

Hiroyuki Ishida; Motohiko Kusakabe; Hiroshi Okada

2014-08-11T23:59:59.000Z

110

An Improved Reaction Rate Formulation for Charged-Particle Induced Thermonuclear Reaction of {sup 2}H(d,{gamma}){sup 4}He  

SciTech Connect

The reaction rate formula utilized in compilations such as the Nuclear Astrophysics Compilation of Reaction Rates (NACRE) uses low energy approximation due to temperatures in stars are in the region of a few keVs. Most nuclear reaction experiments were done in MeV range and the interior temperatures of massive stars are {approx}10{sup 9} K. Hence an improved formulation for calculating the nuclear reaction rate that is applicable to high temperatures is discussed in this work. The exact tunneling probability that is applicable for all energies is obtained by solving the Schroedinger equation. This yields an enhanced expression for the astrophysical S-factor for calculating the thermonuclear reaction rate at high temperature. The thermonuclear reaction rate from this work is applied to the {sup 2}H(d,{gamma}){sup 4}He reaction and is compared with the NACRE compilation. This improved reaction rate can be included in the nuclear reaction network in a Big Bang nucleosynthesis (BBN) code or a stellar nuclear network code.

Aziz, Azni Abdul; Yusof, Norhasliza; Idris, Mahirah; Kassim, Hasan Abu [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-03-30T23:59:59.000Z

111

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

E-Print Network (OSTI)

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...

Fuller, George M; Kusenko, Alexander

2011-01-01T23:59:59.000Z

112

arXiv:hep-ph/0701036v14Jan2007 Braneworld Quintessential Inflation and Sum  

E-Print Network (OSTI)

and quintessence--can occur for a sum of exponentials or cosh potential, a type of potential that arises naturally production and the universe undergoes a transition from primordial inflation to radiation domination well before big bang nucleosynthesis. The transition to an accelerating universe due to quintessence occurs

Gardner, Carl

113

Nuclear physics and cosmology  

SciTech Connect

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.

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

114

Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations  

E-Print Network (OSTI)

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 ...

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

2014-01-01T23:59:59.000Z

115

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

E-Print Network (OSTI)

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.

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

2011-10-28T23:59:59.000Z

116

Universal Lepton Asymmetry: New Constraints from the Cosmic Microwave Background and Primordial Nucleosynthesis  

E-Print Network (OSTI)

We study the primordial nucleosynthesis and cosmic age in the presence of a net lepton asymmetry as well as baryon asymmetry. We explore a previously unnoted region of the parameter space in which very large baryon densities $0.1 \\le \\Omega_b \\le 1$ can be accommodated within the light-element constraints from primordial nucleosynthesis. This parameter space consists of $\

T. Kajino; M. Orito; G. J. Mathews; R. N. Boyd

2002-02-06T23:59:59.000Z

117

Collaborative Research: Neutrinos & Nucleosynthesis in Hot Dense Matter  

SciTech Connect

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.

Reddy, Sanjay

2013-09-06T23:59:59.000Z

118

Nucleosynthesis in neutron-rich ejecta from quark-novae  

E-Print Network (OSTI)

We explore heavy-element nucleosynthesis by rapid neutron capture (r-process) in the decompressing ejecta from the surface of a neutron star. The decompression is triggered by a violent phase transition to strange quark matter (quark-nova scenario). The presence of neutron-rich large Z nuclei (40,95) solar abundance pattern of r-process elements. We highlight the distinguishing features of quark-novae by contrasting it with conventional nucleosynthetic sites such as type II supernovae and neutron star mergers, especially in the context of heavy-element compositions of extremely metal-deficient stars.

Prashanth Jaikumar; Bradley S. Meyer; Kaori Otsuki; Rachid Ouyed

2006-10-04T23:59:59.000Z

119

Neutron-Capture Nucleosynthesis in the First Stars  

E-Print Network (OSTI)

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 a...

Roederer, Ian U; Thompson, Ian B; Shectman, Stephen A; Sneden, Chris

2014-01-01T23:59:59.000Z

120

Neutrino-driven wind simulations and nucleosynthesis of heavy elements  

E-Print Network (OSTI)

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.

A. Arcones; F. -K. Thielemann

2012-07-11T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Nucleosynthesis: Stellar and Solar Abundances and Atomic Data  

E-Print Network (OSTI)

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy -- the progenitors of the halo stars -- responsible for neutron-capture synthesis. Comparisons of abundance trends can be used to understand the chemical evolution of the Galaxy and the nature of heavy element nucleosynthesis. In addition age determinations, based upon long-lived radioactive nuclei abundances, can now be obtained. These stellar abundance determinations depend critically upon atomic data. Improved laboratory transition probabilities have been recently obtained for a number of elements. These new gf values have been used to greatly refine the abundances of neutron-capture elemental abundances in the solar photosphere and in very metal-poor Galactic halo stars. The newly determined stellar abundances are surprisingly consistent with a (relative) Solar System r-process pattern, and are also consistent with abundance predictions expected from such neutron-capture nucleosynthesis.

John J. Cowan; James E. Lawler; Christopher Sneden; E. A. Den Hartog; Jason Collier

2006-05-04T23:59:59.000Z

122

BIG BANG ACOUSTICS SOUND IN THE EARLY UNIVERSE Article for the Acoustical Society of America magazine: ECHOES  

E-Print Network (OSTI)

includes all the associated sounds, can be found on my website at http://www.astro.virginia.edu/dmw8f

Whittle, Mark

123

A constraint on a varying proton--electron mass ratio 1.5 billion years after the Big Bang  

E-Print Network (OSTI)

A molecular hydrogen absorber at a lookback time of 12.4 billion years, corresponding to 10$\\%$ of the age of the universe today, is analyzed to put a constraint on a varying proton--electron mass ratio, $\\mu$. A high resolution spectrum of the J1443$+$2724 quasar, which was observed with the Very Large Telescope, is used to create an accurate model of 89 Lyman and Werner band transitions whose relative frequencies are sensitive to $\\mu$, yielding a limit on the relative deviation from the current laboratory value of $\\Delta\\mu/\\mu=(-9.5\\pm5.4_{\\textrm{stat}} \\pm 5.3_{\\textrm{sys}})\\times 10^{-6}$.

Bagdonaite, J; Murphy, M T; Whitmore, J B

2015-01-01T23:59:59.000Z

124

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

E-Print Network (OSTI)

accelerator designed to explore the structure of the physical vacuum as well as possible forms of new states cannot be seen individually we must explore the confinement mechanism of the physical vacuum state and Shinichiro Tomonaga were among those who solved major problems of nuclear physics and quantum electrodynamics

Kazama, Hokto

125

Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA  

E-Print Network (OSTI)

The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400 keV alpha-beam energy and for comparison also using an americium-beryllium neutron source.

M. Anders; D. Trezzi; A. Bellini; M. Aliotta; D. Bemmerer; C. Broggini; A. Caciolli; H. Costantini; P. Corvisiero; T. Davinson; Z. Elekes; M. Erhard; A. Formicola; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyürky; M. Junker; A. Lemut; M. Marta; C. Mazzocchi; R. Menegazzo; P. Prati; C. Rossi Alvarez; D. Scott; E. Somorjai; O. Straniero; T. Szücs

2013-01-30T23:59:59.000Z

126

Computational Astrophysics Consortium 3 - Supernovae, Gamma-Ray Bursts and Nucleosynthesis  

SciTech Connect

Final project report for UCSC's participation in the Computational Astrophysics Consortium - Supernovae, Gamma-Ray Bursts and Nucleosynthesis. As an appendix, the report of the entire Consortium is also appended.

Woosley, Stan

2014-08-29T23:59:59.000Z

127

Nucleosynthesis in neutron-rich ejecta from Quark-Novae.  

SciTech Connect

We explore heavy-element nucleosynthesis by rapid neutron capture (r-process) in the decompressing ejecta from the surface of a neutron star. The decompression is triggered by a violent phase transition to strange quark matter (quark-nova scenario). The presence of neutron-rich large Z nuclei (40,95) < (Z,A) < (70,177), the large neutron-to-seed ratio, and the low electron fraction Y{sub e} {approx} 0.03 in the decompressing ejecta present favorable conditions for the r-process. We perform network calculations that are adapted to the quark-nova conditions, and which mimic usual (n-{gamma}) equilibrium r-process calculations during the initially cold decompression phase. They match to dynamical r-process calculations at densities below neutron drip (4 x 10{sup 11} g cm{sup -3}). We present results for the final element abundance distribution with and without heating from nuclear reactions, and compare to the solar abundance pattern of r-process elements. We highlight the distinguishing features of quark-novae by contrasting it with conventional nucleosynthetic sites such as type II supernovae and neutron star mergers, especially in the context of heavy-element compositions of extremely metal-deficient stars.

Jaikumar, P.; Ouyed, R.; Otsuki, K.; Meyer, B. S.; Physics; Univ. of Calgary; Univ. of Chicago; Clemson Univ.

2007-01-01T23:59:59.000Z

128

Probing AGB nucleosynthesis via accurate Planetary Nebula abundances  

E-Print Network (OSTI)

The elemental abundances of ten planetary nebulae, derived with high accuracy including ISO and IUE spectra, are analysed with the aid of synthetic evolutionary models for the TP-AGB phase. Model prescriptions are varied until we achieve the simultaneous reproduction of all elemental features, which allows placing important constraints on the characteristic masses and nucleosynthetic processes experienced by the stellar progenitors. First of all, it is possible to separate the sample into two groups of PNe, one indicating the occurrence of only the third dredge-up during the TP-AGB phase, and the other showing also the chemical signature of hot-bottom burning. The former group is reproduced by stellar models with variable molecular opacities (see Marigo 2002), adopting initial solar metallicity, and typical efficiency of the third dredge-up 0.3-0.4. The latter group of PNe, with extremely high He content 0.15TP-AGB progenitors (M > 4.5-5.0 Mo) with LMC composition have suffered a number of very efficient, carbon-poor, dredge-up events. Finally, the neon abundances of the He-rich PNe can be recovered by invoking a significant production of 22Ne during thermal pulses, which would imply a reduced role of the 22Ne(alpha,n)25Mg reaction as neutron source to the s-process nucleosynthesis in these stars.

P. Marigo; J. Bernard-Salas; S. R. Pottasch; A. G. G. M. Tielens; P. R. Wesselius

2003-07-11T23:59:59.000Z

129

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

E-Print Network (OSTI)

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.

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

2002-06-03T23:59:59.000Z

130

CMB  

NLE Websites -- All DOE Office Websites (Extended Search)

Hubble Diagram Hubble Diagram CMB BBN Cosmic Microwave Background One of the predictions that the Big Bang theory leads to, concerns some left over pieces that could tell us the temperature of the universe.. IF we believe that the Big Bang is how the universe began, then theorists predict that we should see a remnant microwave background. It is microwave because that is the area of the spectrum in which it is found. When we look out into space with our bare eyes, we see bright objects and a whole lot of "empty" space. However, if we examine the sky with a radio telescope, we see an almost perfect blackbody spectrum in the microwave spectrum. What is a blackbody and why is it radiating? How did we find the Cosmic Microwave Background? And can we fit a curve to the data taken for the Cosmic

131

Modeling Cosmic Nucleosynthesis | U.S. DOE Office of Science (SC)  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling Cosmic Nucleosynthesis Modeling Cosmic Nucleosynthesis Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » December 2013 Modeling Cosmic Nucleosynthesis First measurements of isotopes produced by Argonne's new CARIBU facility provide insight into the creation of the elements in the universe. Print Text Size: A A A Subscribe FeedbackShare Page Click to enlarge photo. Enlarge Photo Image courtesy of Argonne National Laboratory The Penning trap was used to precisely measure the masses of isotopes

132

Nucleosynthesis in a massive star associated with magnetohydrodynamical jets from collapsars  

SciTech Connect

We investigate the nucleosynthesis during the stellar evolution and the jet-like supernova explosion of a massive star of 70 M{sub Circled-Dot-Operator} having the solar metallicity in the main sequence stage. The nucleosynthesis calculations have been performed with large nuclear reaction networks, where the weak s-, p-, and r-processes are taken into account. As a result s-elements of 60 > A > 90 and r-elements of 90 > A > 160 are highly overproduced relative to the solar system abundances. We find that the Sr-Y-Zr isotopes are primarily synthesized in the explosive nucleosynthesis which could be one of the sites of the lighter element primary process (LEPP).

Ono, M.; Hashimoto, M.; Fujimoto, S.; Kotake, K.; Yamada, S. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan and Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan); Kumamoto National College of Technology, Kumamoto 861-1102 (Japan); Division of Theoretical Astronomy/Center for Computational Astrophysics, National Astronomical Observatory of Japan, Tokyo 181-8588 (Japan); Advanced Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan)

2012-11-12T23:59:59.000Z

133

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

E-Print Network (OSTI)

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)

Eduardo Bravo; Gabriel Martínez-Pinedo

2012-04-09T23:59:59.000Z

134

Supernova SN1987A Bound on Neutrino Spectra for R-Process Nucleosynthesis  

E-Print Network (OSTI)

The neutrino driven wind during a core collapse supernova is an attractive site for r-process nucleosynthesis. The electron fraction $Y_e$ in the wind depends on observable neutrino energies and luminosities. The mean antineutrino energy is limited by supernova SN1987A data while lepton number conservation constrains the ratio of antineutrino to neutrino luminosities. If $Y_e$, in the wind, is to be suitable for rapid neutron capture nucleosynthesis, then the mean electron neutrino energy may be significantly lower then that predicted in present supernova simulations, or there may be new neutrino physics such as oscillations to sterile neutrinos.

C. J. Horowitz

2001-08-07T23:59:59.000Z

135

Activation measurement of the 3He(alpha,gamma)7Be cross section at low energy  

E-Print Network (OSTI)

The nuclear physics input from the 3He(alpha,gamma)7Be cross section is a major uncertainty in the fluxes of 7Be and 8B neutrinos from the Sun predicted by solar models and in the 7Li abundance obtained in big-bang nucleosynthesis calculations. The present work reports on a new precision experiment using the activation technique at energies directly relevant to big-bang nucleosynthesis. Previously such low energies had been reached experimentally only by the prompt-gamma technique and with inferior precision. Using a windowless gas target, high beam intensity and low background gamma-counting facilities, the 3He(alpha,gamma)7Be cross section has been determined at 127, 148 and 169 keV center-of-mass energy with a total uncertainty of 4%. The sources of systematic uncertainty are discussed in detail. The present data can be used in big-bang nucleosynthesis calculations and to constrain the extrapolation of the 3He(alpha,gamma)7Be astrophysical S-factor to solar energies.

D. Bemmerer; F. Confortola; H. Costantini; A. Formicola; Gy. Gyurky; R. Bonetti; C. Broggini; P. Corvisiero; Z. Elekes; Zs. Fulop; 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

2006-09-11T23:59:59.000Z

136

Falk Herwig18 July 2007 Slide 1 Nucleosynthesis and mixing in  

E-Print Network (OSTI)

Falk Herwig18 July 2007 Slide 1 Nucleosynthesis and mixing in the first generations of low July 2007 Slide 2 We have seen yesterday: rotation is important at extremely low and zero metalicity Slide 3 The convective-reactive events occur favorably at Z=0 or extremely low metallicity: ·the entropy

Herwig, Falk

137

Sensitivity study of explosive nucleosynthesis in type Ia supernovae: Modification of individual thermonuclear reaction rates  

Science Journals Connector (OSTI)

Background: Type Ia supernovae contribute significantly to the nucleosynthesis of many Fe-group and intermediate-mass elements. However, the robustness of nucleosynthesis obtained via models of this class of explosions has not been studied in depth until now.Purpose: We explore the sensitivity of the nucleosynthesis resulting from thermonuclear explosions of massive white dwarfs with respect to uncertainties in nuclear reaction rates. We put particular emphasis on indentifying the individual reactions rates that most strongly affect the isotopic products of these supernovae.Method: We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf and have postprocessed the thermodynamic trajectories of every mass shell with a nucleosynthetic code to obtain the chemical composition of the ejected matter. We have considered increases (decreases) by a factor of 10 on the rates of 1196 nuclear reactions (simultaneously with their inverse reactions), repeating the nucleosynthesis calculations after modification of each reaction rate pair. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. From the calculations we have selected the reactions that have the largest impact on the supernova yields, and we have computed again the nucleosynthesis using two or three alternative prescriptions for their rates, taken from the JINA REACLIB database. For the three reactions with the largest sensitivity we have analyzed as well the temperature ranges where a modification of their rates has the strongest effect on nucleosynthesis.Results: 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 two 12C nuclei. The energy of the explosion changes by less than ?4% when the rates of the reactions 12C+12C or 16O+16O are multiplied by a factor of ×10 or ×0.1. The changes in the nucleosynthesis owing to the modification of the rates of these fusion reactions are also 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 2. 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 ?. In general, the yields of Fe-group nuclei are more robust than the yields of intermediate-mass elements. Among the species with yields larger than 10?8M?, 35S has the largest sensitivity to the nuclear reaction rates. It is remarkable that the reactions involving elements with Z>22 have a tiny influence on the supernova nucleosynthesis. Among the charged-particle reactions, the most influential on supernova nucleosynthesis are 30Si+p?31P+?, 20Ne+??24Mg+?, and 24Mg+??27Al+p. The temperatures at which a modification of their rate has a larger impact are in the range 2?T?4 GK.Conclusions: The explosion model (i.e., the assumed conditions and propagation of the flame) chiefly determines the element production of type Ia supernovae and derived quantities such as their luminosity, while the nuclear reaction rates used in the simulations have a small influence on the kinetic energy and final chemical composition of the ejecta. Our results show that the uncertainty in individual thermonuclear reaction rates cannot account for discrepancies of a factor of 2 between isotopic ratios in type Ia supernovae and those in the solar system, especially within the Fe group.

Eduardo Bravo and Gabriel Martínez-Pinedo

2012-05-18T23:59:59.000Z

138

The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars  

E-Print Network (OSTI)

The chemical evolution of the Universe is governed by the chemical yields from stars, which in turn is determined primarily by the initial stellar mass. Even stars as low as 0.9Msun can, at low metallicity, contribute to the chemical evolution of elements. Stars less massive than about 10Msun experience recurrent mixing events that can significantly change the surface composition of the envelope, with observed enrichments in carbon, nitrogen, fluorine, and heavy elements synthesized by the slow neutron capture process (the s-process). Low and intermediate mass stars release their nucleosynthesis products through stellar outflows or winds, in contrast to massive stars that explode as core-collapse supernovae. Here we review the stellar evolution and nucleosynthesis for single stars up to ~10Msun from the main sequence through to the tip of the asymptotic giant branch (AGB). We include a discussion of the main uncertainties that affect theoretical calculations and review the latest observational data, which are...

Karakas, Amanda I

2014-01-01T23:59:59.000Z

139

1997 Reviews, Tables, and Plots in the Review of Particle Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Plots (Alphabetical List) Plots (Alphabetical List) in the 1997 Review of Particle Physics Cut-off date for this update was October 15, 1997. Please use this CITATION. See this same index logically ordered. Having trouble with PostScript files? We have a PostScript help file. Accelerator physics of colliders (8p, 89kb) Astrophysical constants (6p, 111kb) Atomic and nuclear properties of materials (2p, 80kb) Axions and other Very Light Bosons (6p, 59kb) b-flavored Hadrons, Production and Decay (13p, 130kb) B0-Bbar0 Mixing (5p, 86kb) Big-bang cosmology (3p, 65kb) Big-bang nucleosynthesis (8p, 302kb) Cabibbo-Kobayashi-Maskawa mixing matrix (10p, 219kb) Clebsch-Gordan coeff., sph. harmonics, and d functions (2p, 211kb) Collider parameters (high-energy colliders) (3p, 73kb) Compositeness, Searches for Quark and Lepton (5p, 59kb)

140

In vitro and in vivo analysis of [64Cu-NO2A-8-Aoc-BBN(7–14)NH2]: a site-directed radiopharmaceutical for positron-emission tomography imaging of T-47D human breast cancer tumors  

Science Journals Connector (OSTI)

Introduction Human breast cancer, from which the T-47D cell line was derived, is known to overexpress the gastrin-releasing peptide receptor (GRPR) in some cases. Bombesin (BBN), an agonist for the GRPR, has been appended with a radionuclide capable of positron-emission tomography (PET) imaging and therapy. 64Cu-NO2A-8-Aoc-BBN(7–14)NH2 (NO2A=1,4,7-triazacyclononane-1,4-diacetate) has produced high-quality microPET images of GRPR-positive breast cancer xenografted tumors in mice. Methods The imaging probe was synthesized by solid-phase peptide synthesis followed by manual conjugation of the 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) bifunctional chelator and radiolabeling in aqueous solution. The radiolabeled conjugate was subjected to in vitro and in vivo studies to determine its specificity for the GRPR and its pharmacokinetic profile. A T-47D tumor-bearing mouse was imaged with microPET/CT and microMRI imaging. Results The 64Cu-NO2A-8-Aoc-BBN(7–14)NH2 targeting vector was determined to specifically localize in GRPR-positive tissue. Accumulation was observed in the tumor in sufficient quantities to allow for identification of tumors in microPET imaging procedures. For example, uptake and retention in T-47D xenografts at 1, 4 and 24 h were determined to be 2.27±0.08, 1.35±0.14 and 0.28±0.07 % ID/g, respectively. Conclusions The 64Cu-NO2A-8-Aoc-BBN(7–14)NH2 produced high-quality microPET images. The pharmacokinetic profile justifies investigation of this bioconjugate as a potentially useful diagnostic/therapeutic agent. Additionally, the bioconjugate would serve as a good starting point for modification and optimization of similar agents to maximize tumor uptake and minimize nontarget accumulation.

Adam F. Prasanphanich; Lauren Retzloff; Stephanie R. Lane; Prasant K. Nanda; Gary L. Sieckman; Tammy L. Rold; Lixin Ma; Said D. Figueroa; Samantha V. Sublett; Timothy J. Hoffman; Charles J. Smith

2009-01-01T23:59:59.000Z

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141

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

SciTech Connect

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.

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

142

Astronomy/IB C13: Origins: From the Big Bang to the Emergence of Humans Fall 2013 Aug 29 1) The Science of Origins  

E-Print Network (OSTI)

and Plants Invade Land Nov 5 20) Comets, Asteroids, & the Death of Dinosaurs SECTION 10: Fossils Nov 7 21

Wurtele, Jonathan

143

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

SciTech Connect

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.

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

144

SHEDDING NEW LIGHT ON EXPLODING STARS: TERASCALE SIMULATIONS OF NEUTRINO-DRIVEN SUPERNOVAE AND THEIR NUCLEOSYNTHESIS  

SciTech Connect

This project was focused on simulations of core-collapse supernovae on parallel platforms. The intent was to address a number of linked issues: the treatment of hydrodynamics and neutrino diffusion in two and three dimensions; the treatment of the underlying nuclear microphysics that governs neutrino transport and neutrino energy deposition; the understanding of the associated nucleosynthesis, including the r-process and neutrino process; the investigation of the consequences of new neutrino phenomena, such as oscillations; and the characterization of the neutrino signal that might be recorded in terrestrial detectors. This was a collaborative effort with Oak Ridge National Laboratory, State University of New York at Stony Brook, University of Illinois at Urbana-Champaign, University of California at San Diego, University of Tennessee at Knoxville, Florida Atlantic University, North Carolina State University, and Clemson. The collaborations tie together experts in hydrodynamics, nuclear physics, computer science, and neutrino physics. The University of Washington contributions to this effort include the further development of techniques to solve the Bloch-Horowitz equation for effective interactions and operators; collaborative efforts on developing a parallel Lanczos code; investigating the nuclear and neutrino physics governing the r-process and neutrino physics; and exploring the effects of new neutrino physics on the explosion mechanism, nucleosynthesis, and terrestrial supernova neutrino detection.

Haxton, Wick

2012-03-07T23:59:59.000Z

145

Nuclear Astrophysics  

E-Print Network (OSTI)

Nuclear physics has a long and productive history of application to astrophysics which continues today. Advances in the accuracy and breadth of astrophysical data and theory drive the need for better experimental and theoretical understanding of the underlying nuclear physics. This paper will review some of the scenarios where nuclear physics plays an important role, including Big Bang Nucleosynthesis, neutrino production by our sun, nucleosynthesis in novae, the creation of elements heavier than iron, and neutron stars. Big-bang nucleosynthesis is concerned with the formation of elements with A nuclear physics inputs required are few-nucleon reaction cross sections. The nucleosynthesis of heavier elements involves a variety of proton-, alpha-, neutron-, and photon-induced reactions, coupled with radioactive decay. The advent of radioactive ion beam facilities has opened an important new avenue for studying these processes, as many involve radioactive species. Nuclear physics also plays an important role in neutron stars: both the nuclear equation of state and cooling processes involving neutrino emission play a very important role. Recent developments and also the interplay between nuclear physics and astrophysics will be highlighted.

Carl R. Brune

2005-02-28T23:59:59.000Z

146

Neutron capture cross section of unstable 63Ni: implications for stellar nucleosynthesis  

E-Print Network (OSTI)

The $^{63}$Ni($n, \\gamma$) cross section has been measured for the first time at the neutron time-of-flight facility n\\_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian Averaged Cross Sections were calculated for thermal energies from kT = 5 keV to 100 keV with uncertainties around 20%. Stellar model calculations for a 25 M$_\\odot$ star show that the new data have a significant effect on the $s$-process production of $^{63}$Cu, $^{64}$Ni, and $^{64}$Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.

C. Lederer; C. Massimi; S. Altstadt; J. Andrzejewski; L. Audouin; M. Barbagallo; V. Bécares; F. Bevá; F. Belloni; E. Berthoumieux; J. Billowes; V. Boccone; D. Bosnar; M. Brugger; M. Calviani; F. Calviño; D. Cano-Ott; C. Carrapiço; F. Cerutti; E. Chiaveri; M. Chin; N. Colonna; G. Cortés; M. A. Cortés-Giraldo; M. Diakaki; C. Domingo-Pardo; I. Duran; R. Dressler; N. Dzysiuk; C. Eleftheriadis; A. Ferrari; K. Fraval; S. Ganesan; A. R. García; G. Giubrone; M. B. Gómez-Hornillos; I. F. Gonçalves; E. González-Romero; E. Griesmayer; C. Guerrero; F. Gunsing; P. Gurusamy; D. G. Jenkins; E. Jericha; Y. Kadi; F. Käppeler; D. Karadimos; N. Kivel; P. Koehler; M. Kokkoris; G. Korschinek; M. Krtika; J. Kroll; C. Langer; H. Leeb; L. S. Leong; R. Losito; A. Manousos; J. Marganiec; T. Martínez; P. F. Mastinu; M. Mastromarco; M. Meaze; E. Mendoza; A. Mengoni; P. M. Milazzo; F. Mingrone; M. Mirea; W. Mondelaers; C. Paradela; A. Pavlik; J. Perkowski; M. Pignatari; A. Plompen; J. Praena; J. M. Quesada; T. Rauscher; R. Reifarth; A. Riego; F. Roman; C. Rubbia; R. Sarmento; P. Schillebeeckx; S. Schmidt; D. Schumann; G. Tagliente; J. L. Tain; D. Tarrío; L. Tassan-Got; A. Tsinganis; S. Valenta; G. Vannini; V. Variale; P. Vaz; A. Ventura; R. Versaci; M. J. Vermeulen; V. Vlachoudis; R. Vlastou; A. Wallner; T. Ware; M. Weigand; C. Weiß; T. J. Wright; P. Zugec

2013-04-11T23:59:59.000Z

147

Nucleosynthesis in neutrino-driven, aspherical supernovae of population III stars  

SciTech Connect

We examine explosive nucleosynthesis during neutrino-driven, aspherical supernovae of Population III stars, based on two-dimensional (2D) hydrodynamic simulations of the explosion of 11-40M{sub Circled-Dot-Operator} stars with zero metallicity. The magnitude and asymmetry of the explosion energy are estimated with the simulations. By post-processing calculations with a large nuclear reaction network, we have evaluated abundances and masses of ejecta from the aspherical SNe. We find that the evaluated abundance patterns are similar to those observed in extremely metal poor stars, as shown in spherical and 2D models, in which the explosion is manually and spherically initiated. Matter mixing induced via standing accretion shock instability is important for the abundances and masses of the SN ejecta.

Fujimoto, Shin-ichiro; Hashimoto, Masa-aki; Ono, Masaomi; Kotake, Kei [Kumamoto National College of Technology, 2659-2 Suya, Goshi 861-1102 (Japan); Department of Physics, School of Sciences, Kyushu University, Fukuoka 810-8560 (Japan); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); National Astronomical Observatory Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)

2012-11-12T23:59:59.000Z

148

The 40Ca(alpha,gamma)44Ti reaction in the energy regime of supernova nucleosynthesis  

E-Print Network (OSTI)

The 44Ti(t1/2 = 59 y) nuclide, an important signature of supernova nucleosynthesis, has recently been observed as live radioactivity by gamma-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction, 40Ca(alpha,gamma)44Ti (E_cm = 0.6-1.2 MeV/u), by direct off- line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor ~2 over previous estimates and bringing it closer to Cas A observations.

H. Nassar; M. Paul; I. Ahmad; Y. Ben-Dov; J. Caggiano; S. Ghelberg; S. Goriely; J. P. Greene; M. Hass; A. Heger; A. Heinz; D. J. Henderson; R. V. F. Janssens; C. L. Jiang; Y. Kashiv; B. S. Nara Singh; A. Ofan; R. C. Pardo; T. Pennington; K. E. Rehm; G. Savard; R. Scott; R. Vondrasek

2006-01-11T23:59:59.000Z

149

Neutrino Degeneracy and Decoupling: New Limits from Primordial Nucleosynthesis and the Cosmic Microwave Background  

E-Print Network (OSTI)

We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy. We show that neutrinos can begin to decouple at higher temperatures than previous estimates due to several corrections which diminish the neutrino reaction rate. These decoupled neutrinos are therefore not heated as the particle degrees of freedom change. The resultant ratio of the relic neutrino-to-photon temperatures after $e^\\pm$ annihilation can then be significantly reduced by more than a factor of two from that of the standard nondegenerate ratio. This changes the expansion rate and subsequent primordial nucleosynthesis, photon decoupling, and structure formation. In particular we analyze physically plausible lepton-asymmetric models with large $\

M. Orito; T. Kajino; G. J. Mathews; R. N. Boyd

2000-05-23T23:59:59.000Z

150

NUCLEOSYNTHESIS IN TWO-DIMENSIONAL DELAYED DETONATION MODELS OF TYPE Ia SUPERNOVA EXPLOSIONS  

SciTech Connect

For the explosion mechanism of Type Ia supernovae (SNe Ia), different scenarios have been suggested. In these, the propagation of the burning front through the exploding white dwarf (WD) star proceeds in different modes, and consequently imprints of the explosion model on the nucleosynthetic yields can be expected. The nucleosynthetic characteristics of various explosion mechanisms are explored based on three two-dimensional explosion simulations representing extreme cases: a pure turbulent deflagration, a delayed detonation following an approximately spherical ignition of the initial deflagration, and a delayed detonation arising from a highly asymmetric deflagration ignition. Apart from this initial condition, the deflagration stage is treated in a parameter-free approach. The detonation is initiated when the turbulent burning enters the distributed burning regime. This occurs at densities around 10{sup 7} g cm{sup -3}-relatively low as compared to existing nucleosynthesis studies for one-dimensional spherically symmetric models. The burning in these multidimensional models is different from that in one-dimensional simulations as the detonation wave propagates both into unburned material in the high-density region near the center of a WD and into the low-density region near the surface. Thus, the resulting yield is a mixture of different explosive burning products, from carbon-burning products at low densities to complete silicon-burning products at the highest densities, as well as electron-capture products synthesized at the deflagration stage. Detailed calculations of the nucleosynthesis in all three models are presented. In contrast to the deflagration model, the delayed detonations produce a characteristic layered structure and the yields largely satisfy constraints from Galactic chemical evolution. In the asymmetric delayed detonation model, the region filled with electron capture species (e.g., {sup 58}Ni, {sup 54}Fe) is within a shell, showing a large off-set, above the bulk of {sup 56}Ni distribution, while species produced by the detonation are distributed more spherically.

Maeda, K. [Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Roepke, F.K.; Fink, M.; Hillebrandt, W.; Travaglio, C. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching (Germany); Thielemann, F.-K., E-mail: keiichi.maeda@ipmu.j [Department Physik, Universitaet Basel, CH-4056 Basel (Switzerland)

2010-03-20T23:59:59.000Z

151

{sup 44}Ti Nucleosynthesis Lines and Hard X-ray Continuum in Young SNRs: from INTEGRAL to Simbol-X  

SciTech Connect

Supemovae and their remnants are the main Galactic nucleosynthesis sites and the privileged sources of Galactic cosmic rays. The youngest of such remnants can be studied through two distinct observational features: {sup 44}Ti{gamma}-ray lines and the hard X-ray nonthermal continuum emission. The former gives unique information on the nucleosynthesis conditions occuring during the first stages of the explosion, while the latter provides clues on acceleration processes at supernova remnant shocks. In this contribution, we present new INTEGRAL results on Tycho, the remnant of a historical supernova, and on G1.9+0.3, which has been recently unveiled as the youngest Galactic supernova remnant. Expectations with Simbol-X are also addressed.

Renaud, M.; Terrier, R.; Lebrun, F. [Laboratoire APC, CNRS-UMR 7164, Universite Paris 7, 10, rue A. Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Trap, G. [CEA/DSM/IRFU/SAp, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Laboratoire APC, CNRS-UMR 7164, Universite Paris 7, 10, rue A. Domon et Leonie Duquet, 75025 Paris Cedex 13 (France); Decourchelle, A. [CEA/DSM/IRFU/SAp, L'Orme des Merisiers, 91191 Gif-sur-Yvette (France); Vink, J. [University Utrecht, P.O. Box 80000, NL-3508 TA, Utrecht (Netherlands)

2009-05-11T23:59:59.000Z

152

Systematics of Dynamical Mass Ejection, Nucleosynthesis, and Radioactively Powered Electromagnetic Signals from Neutron-star Mergers  

Science Journals Connector (OSTI)

We investigate systematically the dynamical mass ejection, r-process nucleosynthesis, and properties of electromagnetic counterparts of neutron-star (NS) mergers in dependence on the uncertain properties of the nuclear equation of state (EOS) by employing 40 representative, microphysical high-density EOSs in relativistic, hydrodynamical simulations. The crucial parameter determining the ejecta mass is the radius R 1.35 of a 1.35 M ? NS. NSs with smaller R 1.35 ("soft" EOS) eject systematically higher masses. These range from ~10–3 M ? to ~10–2 M ? for 1.35-1.35 M ? binaries and from ~5 ? 10–3 M ? to ~2 ? 10–2 M ? for 1.2-1.5 M ? systems (with kinetic energies between ~5 ? 1049 erg and 1051 erg). Correspondingly, the bolometric peak luminosities of the optical transients of symmetric (asymmetric) mergers vary between 3 ? 1041 erg s–1 and 14 ? 1041 erg s–1 (9 ? 1041 erg s–1 and 14.5 ? 1041 erg s–1) on timescales between ~2 hr and ~12 hr. If these signals with absolute bolometric magnitudes from –15.0 to –16.7 are measured, the tight correlation of their properties with those of the merging NSs might provide valuable constraints on the high-density EOS. The r-process nucleosynthesis exhibits a remarkable robustness independent of the EOS, producing a nearly solar abundance pattern above mass number 130. By the r-process content of the Galaxy and the average production per event the Galactic merger rate is limited to 4 ? 10–5 yr–1 (4 ? 10–4 yr–1) for a soft (stiff) NS EOS, if NS mergers are the main source of heavy r-nuclei. The production ratio of radioactive 232Th to 238U attains a stable value of 1.64-1.67, which does not exclude NS mergers as potential sources of heavy r-material in the most metal-poor stars.

A. Bauswein; S. Goriely; H.-T. Janka

2013-01-01T23:59:59.000Z

153

The evolution and explosion of massive Stars II: Explosive hydrodynamics and nucleosynthesis  

SciTech Connect

The nucleosynthetic yield of isotopes lighter than A = 66 (zinc) is determined for a grid of stellar masses and metallicities including stars of 11, 12, 13, 15, 18, 19, 20, 22, 25, 30, 35, and 40 M{sub {circle_dot}} and metallicities Z = 0, 10{sup {minus}4}, 0.01, 0.1, and 1 times solar (a slightly reduced mass grid is employed for non-solar metallicities). Altogether 78 different model supernova explosions are calculated. In each case nucleosynthesis has already been determined for 200 isotopes in each of 600 to 1200 zones of the presupernova star, including the effects of time dependent convection. Here each star is exploded using a piston to give a specified final kinetic energy at infinity (typically 1.2 {times} 10{sup 51} erg), and the explosive modifications to the nucleosynthesis, including the effects of neutrino irradiation, determined. A single value of the critical {sup 12}C({sub {alpha},{gamma}}){sup 16}O reaction rate corresponding to S(300 keV) = 170 keV barns is used in all calculations. The synthesis of each isotope is discussed along with its sensitivity to model parameters. In each case, the final mass of the collapsed remnant is also determined and often found not to correspond to the location of the piston (typically the edge of the iron core), but to a ``mass cut`` farther out. This mass cut is sensitive not only to the explosion energy, but also to the presupernova structure, stellar mass, and the metallicity. Unless the explosion mechanism, for unknown reasons, provides a much larger characteristic energy in more massive stars, it appears likely that stars larger than about 30 M{sub {center_dot}} will experience considerable reimplosion of heavy elements following the initial launch of a successful shock. While such explosions will produce a viable, bright Type II supernova light curve, lacking the radioactive tail, they will have dramatically reduced yields of heavy elements and may leave black hole remnants of up to 10 and more solar masses.

Woosley, S.E. [California Univ., Santa Cruz, CA (United States); [Lawrence Livermore National Lab., CA (United States); Weaver, T.A. [Lawrence Livermore National Lab., CA (United States)

1995-08-30T23:59:59.000Z

154

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

E-Print Network (OSTI)

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.

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

2013-06-25T23:59:59.000Z

155

Can mirror matter solve the the cosmological lithium problem?  

SciTech Connect

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.

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

156

Standard and non-standard primordial neutrinos  

E-Print Network (OSTI)

The standard cosmological model predicts the existence of a cosmic neutrino background with a present density of about 110 cm^{-3} per flavour, which affects big-bang nucleosynthesis, cosmic microwave background anisotropies, and the evolution of large scale structures. We report on a precision calculation of the cosmic neutrino background properties including the modification introduced by neutrino oscillations. The role of a possible neutrino-antineutrino asymmetry and the impact of non-standard neutrino-electron interactions on the relic neutrinos are also briefly discussed.

P. D. Serpico

2006-08-14T23:59:59.000Z

157

Fitting oscillating string gas cosmology to supernova data  

E-Print Network (OSTI)

In string gas cosmology, extra dimensions are stabilised by a gas of strings. In the matter-dominated era, competition between matter pushing the extra dimensions to expand and the string gas pulling them back can lead to oscillations of the extra dimensions and acceleration in the visible dimensions. We fit this model to supernova data, taking into account the Big Bang Nucleosynthesis constraint on the energy density of the string gas. The fit to the Union set of supernova data is acceptable, but the fit to the ESSENCE data is poor.

Francesc Ferrer; Tuomas Multamaki; Syksy Rasanen

2008-12-22T23:59:59.000Z

158

Fitting oscillating string gas cosmology to supernova data  

Science Journals Connector (OSTI)

In string gas cosmology, extra dimensions are stabilised by a gas of strings. In the matter-dominated era, competition between matter pushing the extra dimensions to expand and the string gas pulling them back can lead to oscillations of the extra dimensions and acceleration in the visible dimensions. We fit this model to supernova data, taking into account the Big Bang Nucleosynthesis constraint on the energy density of the string gas. The fit to the Union set of supernova data is acceptable, but the fit to the ESSENCE data is poor.

Francesc Ferrer; Tuomas Multamäki; Syksy Räsänen

2009-01-01T23:59:59.000Z

159

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

E-Print Network (OSTI)

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.

A. Arcones; G. Martinez-Pinedo

2010-12-14T23:59:59.000Z

160

The r-process nucleosynthesis during the decompression of neutron star crust material  

SciTech Connect

About half of the nuclei heavier than iron observed in nature are produced by the so-called 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, for which essentially no experimental data exist. The present paper 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. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.

Goriely, S. [Institut d'Astronomie et d'Astrophysique, CP-226, Université Libre de Bruxelles, 1050 Brussels (Belgium); Bauswein, A. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece and Max-Planck-Institut für Astrophysik, Postfach 1317, 85741 Garching (Germany); Janka, H.-T. [Max-Planck-Institut für Astrophysik, Postfach 1317, 85741 Garching (Germany); Sida, J.-L.; Lemaître, J.-F.; Panebianco, S. [C.E.A. Saclay, Irfu/Service de Physique Nucléaire, 91191 Gif-sur-Yvette (France); Dubray, N.; Hilaire, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

2014-05-02T23:59:59.000Z

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161

The r-process nucleosynthesis: a continued challenge for nuclear physics and astrophysics  

E-Print Network (OSTI)

The identification of the astrophysical site and the specific conditions in which r-process nucleosynthesis takes place remain unsolved mysteries of astrophysics. The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the radiative neutron capture rates by exotic nuclei close to the neutron drip line and the fission probabilities of heavy neutron-rich nuclei. These quantities are particularly relevant to determine the composition of the matter resulting from the decompression of initially cold neutron star matter. New detailed r-process calculations are performed and the final composition of ejected inner and outer neutron star crust material is estimated. We discuss the impact of the many uncertainties in the astrophysics and nuclear physics on the final composition of the ejected matter. The similarity between the predicted and the solar abundance pattern for A > 140 nuclei as well as the robustness of the prediction with varied input parameters makes this scenario one of the most promising that deserves further exploration.

S. Goriely; P. Demetriou; H. -Th. Janka; J. M. Pearson; M. Samyn

2004-10-19T23:59:59.000Z

162

MESA and NuGrid Simulations of Classical Nova Outbursts: ONe Nova and Nucleosynthesis  

E-Print Network (OSTI)

Classical novae are the result of thermonuclear flashes of H accreted by CO or ONe white dwarfs, leading eventually to the dynamic ejection of the surface layers. These are observationally known to be enriched in heavy elements, such as C, O and Ne that must originate in layers below the H-flash convection zone. Building on our previous work we now present stellar evolution simulations of ONe nova, and provide a comprehensive comparison of our models with previous work. Some of our models include exponential convective boundary mixing model to account for the observed enrichment of the ejecta even when accreting material with a solar abundance distribution. Our models produce maximum temperature evolution profiles and nucleosynthesis yields in good agreement with models that generate enriched ejecta by assuming that the accreted material was pre-enriched. We confirm for ONe nova the result we reported previously, i.e. we found that 3He can be produced in situ in solar-composition envelopes accreted with slow ...

Denissenkov, Pavel A; Pignatari, Marco; Trappitsch, Reto; Ritter, Christian; Herwig, Falk; Battino, Umberto; Setoodehnia, Kiana

2013-01-01T23:59:59.000Z

163

Nucleosynthesis in the Hot Convective Bubble in Core-Collapse Supernovae  

SciTech Connect

As an explosion develops in the collapsed core of a massive star, neutrino emission drives convection in a hot bubble of radiation, nucleons, and pairs just outside a proto-neutron star. Shortly thereafter, neutrinos drive a wind-like outflow from the neutron star. In both the convective bubble and the early wind, weak interactions temporarily cause a proton excess (Y{sub e} {approx}> 0.50) to develop in the ejected matter. This situation lasts for at least the first second, and the approximately 0.05-0.1 M{sub {circle_dot}} that is ejected has an unusual composition that may be important for nucleosynthesis. Using tracer particles to follow the conditions in a two-dimensional model of a successful supernova explosion calculated by Janka, Buras, and Rampp (2003), they determine the composition of this material. most of it is helium and {sup 56}Ni. The rest is relatively rare species produced by the decay of proton-rich isotopes unstable to positron emission. In the absence of pronounced charged-current neutrino capture, nuclear flow will be held up by long-lived waiting point nuclei in the vicinity of {sup 64}Ge. The resulting abundance pattern can be modestly rich in a few interesting rare isotopes like {sup 45}Sc, {sup 49}Ti, and {sup 64}Zn. The present calculations imply yields that, when compared with the production of major species in the rest of the supernova, are about those needed to account for the solar abundance of {sup 45}Sc and {sup 49}Ti. Since the synthesis will be nearly the same in stars of high and low metallicity, the primary production of these species may have discernible signatures in the abundances of low metallicity stars. They also discuss uncertainties in the nuclear physics and early supernova evolution to which abundances of interesting nuclei are sensitive.

Pruet, J; Woosley, S E; Buras, R; Janka, H; Hoffman, R D

2004-09-02T23:59:59.000Z

164

Inhomogeneous primordial nucleosynthesis and new abundance constraints on {Omega}{sub b}h{sup 2}  

SciTech Connect

We discuss the upper limit to the baryonic contribution to the closure density. We consider effects of new observational and theoretical uncertainties in the primordial light element abundances, and the effects of fluctuation geometry on the inhomogeneous nucleosynthesis yields. We also consider implications of the possible detection of a high D/H abundance in a Lyman-{alpha} absorption cloud at high redshift and the implied chemical evolution effects of a high deuterium abundance. We show that there exists a region of the parameter space for inhomogeneous models in which a somewhat higher baryonic contribution to the closure density is possible than that allowed in standard homogeneous models. This result is contrary to some other recent studies and is due to both geometry and recently revised uncertainties in primordial light-element abundances, particularly {sup 7}Li. We find that the presently adopted abundance constraints are consistent with a contribution of baryons to the closure density as high as {Omega}{sub b}h{sub 50}{sup 2} {le} 0.11 ({eta} {le} 7 {times} 10{sup {minus}10}). This corresponds to a 20% increase over the limit from standard homogeneous models ({Omega}{sub b}h{sub 50}{sup 2} {le} 0.08, {eta} {le} 5.8 {times} 10{sup {minus}10}). With a high deuterium abundance the upper limits for the inhomogeneous and homogeneous models would be {Omega}{sub b}h{sub 50}{sup 2} {le} 0.04 and 0.03 ({eta} {le} 2.6 {times} 10{sup {minus}10} and 1.9 {times} 10{sup {minus}10}), respectively. Even higher limits could be obtained by further relaxing the presently accepted primordial lithium abundance constraint as some have proposed.

Mathews, G.J. [Notre Dame Univ., IN (United States). Dept. of Physics]|[Lawrence Livermore National Lab., CA (United States)]|[National Astronomical Observatory of Japan, Tokyo (Japan); Kajino, T.; Orito, M. [National Astronomical Observatory of Japan, Tokyo (Japan)

1995-07-20T23:59:59.000Z

165

Nucleosynthesis-relevant conditions in neutrino-driven supernova outflows. I. Spherically symmetric hydrodynamic simulations  

E-Print Network (OSTI)

We investigate the behavior and consequences of the reverse shock that terminates the supersonic expansion of the baryonic wind which is driven by neutrino heating off the surface of (non-magnetized) new-born neutron stars in supernova cores. To this end we perform long-time hydrodynamic simulations in spherical symmetry. In agreement with previous relativistic wind studies, we find that the neutrino-driven outflow accelerates to supersonic velocities and in case of a compact, about 1.4 solar mass (gravitational mass) neutron star with a radius of about 10 km, the wind reaches entropies of about 100 k_B per nucleon. The wind, however, is strongly influenced by the environment of the supernova core. It is decelerated and shock-heated abruptly by a termination shock that forms when the supersonic outflow collides with the slower preceding supernova ejecta. The radial position of this reverse shock varies with time and depends on the strength of the neutrino wind and the different conditions in progenitor stars with different masses and structure. Its basic properties and behavior can be understood by simple analytic considerations. We demonstrate that the entropy of matter going through the reverse shock can increase to a multiple of the asymptotic wind value. Seconds after the onset of the explosion it therefore can exceed 400 k_B per nucleon. The temperature of the shocked wind has typically dropped to about or less than 10^9 K, and density and temperature in the shock-decelerated matter continue to decrease only very slowly. Such conditions might strongly affect the important phases of supernova nucleosynthesis in a time and progenitor dependent way. (abridged)

A. Arcones; H. -Th. Janka; L. Scheck

2006-12-20T23:59:59.000Z

166

A resolution of the cosmic Lithium problem  

E-Print Network (OSTI)

In 1982, Monique and Francois Spite discovered that the 7Li abundance in the atmosphere of old metal-poor dwarf stars in the galactic halo was independent of metallicity and temperature. Since then, 7Li abundance in the Universe has become a subject of intrigue, because there is less of it in Population II dwarf stars (by a factor of 3) than standard big bang nucleosynthesis predicts. Here we show how quark-novae (QNe) occurring in the wake of Pop. III stars, can elegantly produce an A(Li) ~ 2.2 Lithium plateau in Pop. II (low-mass) stars formed in the pristine cloud swept up by the mixed SN+QN ejecta. We also find an increase in the scatter as well as an eventual drop in A(Li) below the Spite plateau values for very low metallicity ([Fe/H] < -3) in excellent agreement with observations. We propose a solution to the discrepancy between the Big Bang Nucleosynthesis 7Li abundance and the Spite plateau and list some implications and predictions of our model.

Rachid Ouyed

2014-02-20T23:59:59.000Z

167

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

E-Print Network (OSTI)

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.

Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

2008-06-18T23:59:59.000Z

168

Cosmological Deuterium Abundance and the Baryon Density of the Universe  

E-Print Network (OSTI)

Standard big bang nucleosynthesis (BBNS) promises accurate predictions of the primordial abundances of deuterium, helium-3, helium-4 and lithium-7 as a function of a single parameter. Previous measurements have nearly always been interpreted as confirmation of the model (Copi, Schramm & Turner 1995). Here we present a measurement of the deuterium to hydrogen ratio (D/H) in a newly discovered high redshift metal-poor gas cloud at redshift $z=2.504$. This confirms our earlier measurement of D/H (Tytler, Fan & Burles 1996), and together they give the first accurate measurement of the primordial D abundance, and a ten fold improvement in the accuracy of the cosmological density of ordinary matter.This is a high density, with most ordinary matter unaccounted or dark, which is too high to agree with measurements of the primordial abundances of helium-4 and lithium-7. Since the D/H measurement is apparently simple, direct, accurate and highly sensitive, we propose that helium requires a systematic correction, and that population II stars have less than the primordial abundance of $^7$Li. Alternatively, there is no concordance between the light element abundances, and the simple model of the big bang must be incomplete and lacking physics, or wrong.

Scott Burles; David Tytler

1996-03-19T23:59:59.000Z

169

The Search for a Primordial Magnetic Field  

E-Print Network (OSTI)

Magnetic fields appear wherever plasma and currents can be found. As such, they thread through all scales in Nature. It is natural, therefore, to suppose that magnetic fields might have been formed within the high temperature environments of the big bang. Such a primordial magnetic field (PMF) would be expected to arise from and/or influence a variety of cosmological phenomena such as inflation, cosmic phase transitions, big bang nucleosynthesis, the cosmic microwave background (CMB) temperature and polarization anisotropies, the cosmic gravity wave background, and the formation of large-scale structure. In this review, we summarize the development of theoretical models for analyzing the observational consequences of a PMF. We also summarize the current state of the art in the search for observational evidence of a PMF. In particular we review the framework needed to calculate the effects of a PMF power spectrum on the CMB and the development of large scale structure. We summarize the current constraints on the PMF amplitude $B_\\lambda$ and the power spectral index $n_B$ and discuss prospects for better determining these quantities in the near future.

Dai G. Yamazaki; Toshitaka Kajino; Grant J. Mathew; Kiyotomo Ichiki

2012-04-16T23:59:59.000Z

170

Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes  

E-Print Network (OSTI)

Employing spectra obtained with the new Keck I HIRES near-UV sensitive detector, we have performed a comprehensive chemical composition analysis of the binary blue metal-poor star CS29497-030. Abundances for 29 elements and upper limits for an additional seven have been derived, concentrating on elements largely produced via neutron-capture nucleosynthesis. Included in our analysis are the two elements that define the termination point of the slow neutron-capture process, lead and bismuth. We determine an extremely high value of [Pb/Fe] = +3.65 +/- 0.07 (sigma = 0.13) from three features, supporting the single-feature result obtained in previous studies. We also detect Bi for the first time in a metal-poor star. Our derived Bi/Pb ratio is in accord with those predicted from the most recent FRANEC calculations of the slow neutron-capture process in low-mass AGB stars. We find that the neutron-capture elemental abundances of CS29497-030 are best explained by an AGB model that also includes very significant amounts of pre-enrichment of rapid neutron-capture process material in the protostellar cloud out of which the CS29497-030 binary system formed. Thus, CS29497-030 is both an ``r+s'' and ``extrinsic AGB'' star. Furthermore, we find that the mass of the AGB model can be further constrained by the abundance of the light odd-element [Na/Fe] which is sensitive to the neutron excess.

Inese I. Ivans; Christopher Sneden; Roberto Gallino; John J. Cowan; George W. Preston

2005-04-29T23:59:59.000Z

171

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

E-Print Network (OSTI)

in turn point to short ranges. Finally, many MANETs need to be energy conserving which again implies Moulton Street Cambridge, MA 02138 Approved for Public Release. Distribution Unlimited #12;Ultra Low communication ranges foretell MANETs with very large diameters. Indeed, an architecture where dense low

Ramanathan, Ram

172

KMN  

NLE Websites -- All DOE Office Websites (Extended Search)

Kenneth M. Nollett Kenneth M. Nollett Complete Curriculum Vitae available as PDF file Astrophysics at Argonne lunch seminar Biographical sketch 1995 S.B., Massachusetts Institute of Technology 2000 Ph.D., The University of Chicago 2000-02 Postdoctoral Scholar, California Institute of Technology 2002-03 Research Associate, Institute for Nuclear Theory, University of Washington 2003-08 Assistant Physicist, Argonne National Laboratory 2008-12 Physicist, Argonne National Laboratory Publications ADS Search Google Scholar Nuclear reaction rates and primordial 6Li Kenneth M. Nollett, Martin Lemoine, and David N. Schramm Phys. Rev. C 56, 1144 (1997) Sharpening the predictions of big-bang nucleosynthesis Scott Burles, Kenneth M. Nollett, James W. Truran, and Michael S. Turner Phys. Rev. Lett. 82, 4176 (1999)

173

William Fowler and Elements in the Stars  

NLE Websites -- All DOE Office Websites (Extended Search)

William Fowler and Elements in the Stars Resources with Additional Information William A. Fowler Courtesy AIP Emilio Segrè Visual Archives 'William A. Fowler ... shared the 1983 Nobel Prize in physics for his research into the creation of chemical elements inside stars ... . During his career in nuclear physics and nuclear astrophysics, which spanned more that 60 years, Fowler was primarily concerned with studies of fusion reactions--how the nuclei of lighter chemical elements fuse to create the heavier ones in a process known as nucleosynthesis. In 1957, Fowler coauthored ... the seminal paper "Synthesis of the Elements in the Stars", [which] showed that all of the elements from carbon to uranium could be produced by nuclear processes in stars, starting only with the hydrogen and helium produced in the Big Bang.

174

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

3, 2007 3, 2007 Subscribe | Contact Fermilab Today | Archive | Classifieds Search GO Calendar Thurs., May 3 1:00 p.m. ALCPG ILC Physics and Detector Seminar - Hornets' Nest WH-8XO Speaker: J. Repond, Argonne National Laboratory Title: Status Report of RPC/GEM Vertical Slice Test 2:30 p.m. Theoretical Physics Seminar - Curia II Speaker: M. Pospelov, University of Victoria Title: Particle Physics Catalysis of Big Bang Nucleosynthesis 3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over THERE WILL BE NO ACCELERATOR PHYSICS AND TECHNOLOGY SEMINAR TODAY 6:00 p.m. UTeV Seminar - 1 West Speaker: A. Chou, Fermilab Title: Ultra High Energy Cosmic Rays Fri., May 4 3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over 4:00 p.m. Joint Experimental-Theoretical Physics Seminar - 1 West

175

Reconstructing the cosmic evolution of the chemical elements  

E-Print Network (OSTI)

The chemical elements are created in nuclear fusion processes in the hot and dense cores of stars. The energy generated through nucleosynthesis allows stars to shine for billions of years. When these stars explode as massive supernovae, the newly made elements are expelled, chemically enriching the surrounding regions. Subsequent generations of stars are formed from gas that is slightly more element enriched than that from which previous stars formed. This chemical evolution can be traced back to its beginning soon after the Big Bang by studying the oldest and most metal-poor stars still observable in the Milky Way today. Through chemical analysis, they provide the only available tool for gaining information about the nature of the short-lived first stars and their supernova explosions more than thirteen billion years ago. These events set in motion the transformation of the pristine universe into a rich cosmos of chemically diverse planets, stars, and galaxies.

Frebel, Anna

2014-01-01T23:59:59.000Z

176

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

E-Print Network (OSTI)

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.

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

177

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 (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.

178

Spherically symmetric cosmological spacetimes with dust and radiation — numerical implementation  

SciTech Connect

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.

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

179

Time of primordial Be-7 conversion into Li-7, energy release and doublet of narrow cosmological neutrino lines  

E-Print Network (OSTI)

One of the important light elements created during the big bang nucleosynthesis is Be-7 which then decays to Li-7 by electron capture when recombination becomes effective but well before the Saha equilibrium recombination is reached. This means that Be-7 should wait until its recombination epoch even though the half-life of the hydrogenic beryllium atom is only 106.4 days. We calculate when the conversion from primordial Be-7 to Li-7 occurs taking into account the population of the hyperfine structure sublevels and solving the kinetic equations for recombination, photoionization and conversion rate. We also calculate the energies and the spectrum of narrow neutrino doublet lines resulting from Be-7 decay.

Rishi Khatri; Rashid A. Sunyaev

2010-09-20T23:59:59.000Z

180

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

E-Print Network (OSTI)

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.

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

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Dark matter interacts with variable vacuum energy  

E-Print Network (OSTI)

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) scenario with two interacting components, dark matter and variable vacuum energy (VVE) densities, plus two decoupled components, one is a baryon term while the other behaves as a radiation component. We consider a linear interaction in the derivative dark component density. We apply the $\\chi^2$ method to the observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era for the model. It turns out that our model fulfills the severe bound of $\\Omega_{x}(z\\simeq 1100)survey, the future constraints achievable by Euclid and CMBPol experiments, reported for the behavior of the dark energy at early times, and fulfills the stringent bound $\\Omega_{x}(z\\simeq 10^{10})<0.04$ at $2\\sigma$ level in the big-bang nucleosynthesis epoch. We a...

G, Iván E Sánchez

2014-01-01T23:59:59.000Z

182

Cosmological Constraints on Strongly Coupled Moduli from Cosmic Strings  

E-Print Network (OSTI)

Cosmological constraints on moduli, whose coupling to matter is stronger than Planck mass suppressed coupling, are derived. In particular, moduli are considered to be produced by oscillating loops of cosmic strings and constraints are obtained from their effects on big bang nucleosynthesis and their contribution to diffuse gamma ray background and dark matter. Large volume and warped Type-IIB flux compactifications are taken as examples where strongly coupled moduli are present. Finally, the constraints on cosmic string tension, modulus mass and modulus coupling constant are obtained and it is shown that the constraints are relaxed significantly when the coupling constant is large enough. In addition, the effects of thermal production of moduli are considered and the corresponding constraints are derived.

Eray Sabancilar

2009-10-29T23:59:59.000Z

183

Dissipative hidden sector dark matter  

E-Print Network (OSTI)

A simple way of explaining dark matter without modifying known Standard Model physics is to require the existence of a hidden sector, which interacts with the visible one predominantly via gravity. We consider a hidden sector containing two stable particles charged under an unbroken $U(1)^{'}$ gauge symmetry, hence featuring dissipative interactions. The massless gauge field associated with this symmetry can interact via kinetic mixing with the ordinary photon. In fact, such an interaction of strength $\\epsilon \\sim 10^{-9}$ appears to be necessary in order to explain galactic structure. We calculate the effect of this new physics on Big Bang Nucleosynthesis and its contribution to the relativistic energy density at Hydrogen recombination. Subsequently we examine the process of dark recombination, during which neutral dark states are formed, which is important for large-scale structure formation. We then analyze the phenomenology of our model in the context of galactic structure, and find that it can reproduc...

Foot, R

2014-01-01T23:59:59.000Z

184

Explosive Nucleosynthesis in Stars  

Science Journals Connector (OSTI)

... in hydrostatic equilibrium, with considerable effect on the abundances of the ejected matter. The overheating may result either from the fact that the fuels first ignite in a degenerate electron ... pressure wave propagates outward from an exploding core. In either case, large amounts of thermal energy are liberated in a time short compared with the star's ability to compensate ...

W. DAVID ARNETT; DONALD D. CLAYTON

1970-08-22T23:59:59.000Z

185

New Blog Seeks Out the "Next Big Thing" | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Money 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...

186

Astronomy at the South Pole  

Science Journals Connector (OSTI)

Polar astronomers working with submillimeter telescopes are measuring the cosmic microwave background radiation left over from the Big Bang, mapping our galaxy in the spectral line...

Wright, Gregory

2004-01-01T23:59:59.000Z

187

August 2014  

NLE Websites -- All DOE Office Websites (Extended Search)

he has worked on developing fully autonomous "thinking telescopes" that catch gamma-ray bursts-the biggest explosions since the Big Bang. Read about his scientific research:...

188

Press Pass - Press Releases  

NLE Websites -- All DOE Office Websites (Extended Search)

that neutrinos may have played in the evolution of the universe. If muon neutrinos transform into electron neutrinos, neutrinos could be the reason that the big bang produced...

189

Rob Roser | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Roser About Us Rob Roser - Head, Fermilab Scientific Computing Division Most Recent Supercomputing: A Toolbox to Simulate the Big Bang and Beyond September 19...

190

E-Print Network 3.0 - astrophysically relevant energies Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

environments ranging from the Big Bang to the inner workings... to determine thermonuclear reaction rates and Q-values to determine ... Source: Controlled Fusion Atomic Data...

191

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

E-Print Network (OSTI)

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.

T. Kiang

2003-05-27T23:59:59.000Z

192

hep.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Bang * Fundamental parameters of cosmology - e.g. Planck results assumed by all Dark Energy missions * Highest energy physics - Big Bang as ultimate particle accelerator CMB...

193

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

Science Journals Connector (OSTI)

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 a 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, ?-ray bursts, classical novae, x-ray bursts, superbursts and stellar mergers.

Jordi José; Christian Iliadis

2011-01-01T23:59:59.000Z

194

Primordial black holes from temporally enhanced curvature perturbation  

E-Print Network (OSTI)

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.

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

2014-06-02T23:59:59.000Z

195

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

E-Print Network (OSTI)

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.

Sergey Dubovichenko; Albert Dzhazairov-Kakhramanov; Nadezhda Afanasyeva

2014-01-28T23:59:59.000Z

196

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

SciTech Connect

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.

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

197

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network (OSTI)

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing scintillation light that is detected using photomultiplier tubes. Statistical limitations of the previous apparatus will be alleviated by significant increases in field strength and trap volume resulting in twenty times more trapped neutrons.

C. M. O'Shaughnessy; R. Golub; K. W. Schelhammer; C. M. Swank; P. -N. Seo; P. R. Huffman; S. N. Dzhosyuk; C. E. H. Mattoni; L. Yang; J. M. Doyle; K. J. Coakley; A. K. Thompson; H. P. Mumm; S. K. Lamoreaux; G. Yang

2009-03-31T23:59:59.000Z

198

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network (OSTI)

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing sci...

O'Shaughnessy, C M; Schelhammer, K W; Swank, C M; Seo, P -N; Huffman, P R; Dzhosyuk, S N; Mattoni, C E H; Yang, L; Doyle, J M; Coakley, K J; Thompson, A K; Mumm, H P; Lamoreaux, S K; Yang, G

2009-01-01T23:59:59.000Z

199

Spatial Variability in the Ratio of Interstellar Atomic Deuterium to Hydrogen. I. Observations toward delta Orionis by the Interstellar Medium Absorption Profile Spectrograph  

E-Print Network (OSTI)

Studies of the abundances of deuterium in different astrophysical sites are of fundamental importance to answering the question about how much deuterium was produced during big bang nucleosynthesis and what fraction of it was destroyed later. With this in mind, we used the Interstellar Medium Absorption Profile Spectrograph (IMAPS) on the ORFEUS-SPAS II mission to observe at a wavelength resolution of 4 km/s (FWHM) the L-delta and L-epsilon absorption features produced by interstellar atomic deuterium in the spectrum of delta Ori A. A chi-square analysis indicated that 0.96 atomic ratio of D to H, we measured the L-alpha absorption features in 57 spectra of delta Ori in the IUE archive. From our measurement of N(H I)= 1.56e20 cm^{-2}, we found that N(D I)/N(H I)= 7.4(+1.9,-1.3)e-6 (90% confidence). Our result for D/H contrasts with the more general finding along other lines of sight that D/H is approximately 1.5e-5. The underabundance of D toward delta Ori A is not accompanied by an overabundance of N or O relative to H, as one might expect if the gas were subjected to more stellar processing than usual.

Edward B. Jenkins; Todd M. Tripp; Przemyslaw R. Wozniak; Ulysses J. Sofia; G. Sonneborn

1999-01-28T23:59:59.000Z

200

Unified description of screened modified gravity  

Science Journals Connector (OSTI)

We consider modified gravity models driven by a scalar field whose effects are screened in high density regions due to the presence of nonlinearities in its interaction potential and/or its coupling to matter. Our approach covers chameleon, f(R) gravity, dilaton and symmetron models and allows a unified description of all these theories. We find that the dynamics of modified gravity are entirely captured by the time variation of the scalar field mass and its coupling to matter evaluated at the cosmological minimum of its effective potential, where the scalar field has sat since an epoch prior to big bang nucleosynthesis. This new parametrization of modified gravity allows one to reconstruct the potential and coupling to matter and therefore to analyze the full dynamics of the models, from the scale dependent growth of structures at the linear level to nonlinear effects requiring N-body simulations. This procedure is illustrated with explicit examples of reconstruction for chameleon, dilaton, f(R) and symmetron models.

Philippe Brax; Anne-Christine Davis; Baojiu Li; Hans A. Winther

2012-08-08T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Dark matter interacts with variable vacuum energy  

E-Print Network (OSTI)

We investigate a spatially flat Friedmann-Robertson-Walker (FRW) scenario with two interacting components, dark matter and variable vacuum energy (VVE) densities, plus two decoupled components, one is a baryon term while the other behaves as a radiation component. We consider a linear interaction in the derivative dark component density. We apply the $\\chi^2$ method to the observational Hubble data for constraining the cosmological parameters and analyze the amount of dark energy in the radiation era for the model. It turns out that our model fulfills the severe bound of $\\Omega_{x}(z\\simeq 1100)measurements from Planck survey, the future constraints achievable by Euclid and CMBPol experiments, reported for the behavior of the dark energy at early times, and fulfills the stringent bound $\\Omega_{x}(z\\simeq 10^{10})<0.04$ at $2\\sigma$ level in the big-bang nucleosynthesis epoch. We also examine the cosmic age problem at high redshift associated with the old quasar APM 08279+5255 and estimate the age of the universe today.

Iván E. Sánchez G

2014-05-06T23:59:59.000Z

202

Neutrinoless double-beta decay with three or four neutrino mixing  

E-Print Network (OSTI)

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.

C. Giunti

1999-06-07T23:59:59.000Z

203

Pion-less Effective Field Theory on Low-Energy Deuteron Electro-Disintegration  

E-Print Network (OSTI)

In view of its relation to Big-Bang Nucleo-Synthesis and a reported discrepancy between nuclear models and data taken at S-DALINAC, electro-induced deuteron break-up 2H(e,e' p)n is studied at momentum transfer qelectric dipole currents and at NLO for magnetic ones converges order-by-order better than quantitatively predicted and contains no free parameter. It is at this order determined by simple, well-known observables. Decomposing the doubly differential cross-section into the longitudinal-plus-transverse (L+T), transverse-transverse (TT) and longitudinal-transverse interference (LT) terms, we find excellent agreement with a potential-model calculation by Arenh"ovel et al using the Bonn potential. Theory and data also agree well on \\sigma_{L+T}. There is however no space on the theory-side for the discrepancy of up to 30%, 3-\\sigma between theory and experiment in \\sigma_{LT}. From universality, we conclude that no theoretical approach with the correct deuteron asymptotic wave-function can explain the data. Un-determined short-distance contributions that could affect \\sigma_{LT} enter only at high orders, i.e. at the few-percent level. We notice some issues with the kinematics and normalisation of the data reported.

Stefan Christlmeier; Harald W. Griesshammer

2008-03-09T23:59:59.000Z

204

Particle Data Group - Errata 2008  

NLE Websites -- All DOE Office Websites (Extended Search)

8 Review of Particle Physics 8 Review of Particle Physics C. Amlser et al., Physics Letters B667, 1 (2008) During the time between editions of the Review of Particle Physics and the Particle Physics Booklet, we often find a number of errata. We correct most errata on our WWW pages. If you should find errata that are not known to us, please send mail to pdg @ lbl.gov. Pages 228, 1316 of the full Review (page 3 of the Web version below): Big-Bang Nucleosynthesis (December 18, 2008): The bottom horizontal axis label of Figure 20.1 should read: Baryon-to-photon ratio η x 1010 (and not η x 10-10); Pages 259, 1319 of the full Review (page 17 of the Web version below): Cosmic Rays (December 19, 2008): The vertical axis label of Figure 24.10 should read: E3dN/dE [m-2sr-1eV2] (and not eV-2)

205

Cosmological Tests of Coupled Galileons  

E-Print Network (OSTI)

We investigate the cosmological properties of Galileon models with positive kinetic terms. We include both conformal and disformal couplings to matter and focus on constraints on the theory that arise because of these couplings. The disformal coupling to baryonic matter is extremely constrained by astrophysical and particle physics effects. The disformal coupling to photons induces a cosmological variation of the speed of light and therefore distortions of the Cosmic Microwave Background spectrum which are known to be very small. The conformal coupling to baryons leads to a variation of particle masses since Big Bang Nucleosynthesis which is also tightly constrained. We consider the background cosmology of Galileon models coupled to Cold Dark Matter (CDM), photons and baryons and impose that the speed of light and particle masses respect the observational bounds on cosmological time scales. We find that requiring that the equation of state for the Galileon models must be close to -1 now restricts severely their parameter space and can only be achieved with a combination of the conformal and disformal couplings. This leads to large variations of particle masses and the speed of light which are not compatible with observations. As a result, we find that cosmological Galileon models are viable dark energy theories coupled to dark matter but their couplings, both disformal and conformal, to baryons and photons must be heavily suppressed making them only sensitive to CDM.

Philippe Brax; Clare Burrage; Anne-Christine Davis; Giulia Gubitosi

2014-11-27T23:59:59.000Z

206

Fermilab | Science | Particle Physics | Muons  

NLE Websites -- All DOE Office Websites (Extended Search)

force at the time of the big bang? How did the universe change from being dominated by energy and radiation to the one we see today, made of both visible and dark matter? Muons...

207

The physics, chemistry and dynamics of explosions  

Science Journals Connector (OSTI)

...scenarios that range from the Big Bang, to thermonuclear explosions in stars, to magnetohydrodynamic...chemical reactions or solar coronal thermonuclear reactions, they are not generally...explosions include magnetohydrodynamic and thermonuclear energy sources, mentioned previously...

2012-01-01T23:59:59.000Z

208

The physics, chemistry and dynamics of explosions  

Science Journals Connector (OSTI)

...the development of nuclear fusion as an energy source. The...range from the Big Bang, to thermonuclear explosions in stars, to...reactions or solar coronal thermonuclear reactions, they are not...include magnetohydrodynamic and thermonuclear energy sources, mentioned...

2012-01-01T23:59:59.000Z

209

1  

NLE Websites -- All DOE Office Websites (Extended Search)

hundred million years after the Big Bang and began to transform the universe from a cold, dark, featureless void into the vast cosmic web of galaxies observed today. A few of these...

210

Supercomputers Model 3D Map of Adolescent Universe  

NLE Websites -- All DOE Office Websites (Extended Search)

slice of the adolescent universe-just 3 billion years after the Big Bang. The map shows a web of hydrogen gas that varies from low to high density at a time when the universe was...

211

Lab Astrophysics  

NLE Websites -- All DOE Office Websites (Extended Search)

plasmas in a laboratory, enabling experiments on a state of matter found only in gamma-ray bursts, black holes, active galaxies, and the universe shortly after the Big Bang....

212

Annual modulation of cosmic relic neutrinos  

E-Print Network (OSTI)

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 ...

Safdi, Benjamin R.

213

Fermilab | Science | Inquiring Minds | Questions About Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Hello, At least some contemporary big bang theories begin with the entire universe packed into a very small, atom sized volume. Since black hole densities can be achieved by...

214

The Muon Detection System and W Z --> 3l?(e?, [mu]) cross section measurement at CMS  

E-Print Network (OSTI)

The startup of the Large Hadron Collider will allow scientists to probe energy scales that existed picoseconds after the Big Bang. Monte Carlo samples of many Standard Model processes are produced to simulate the conditions ...

Melachrinos, Constantinos

2008-01-01T23:59:59.000Z

215

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

the Higgs boson and maybe lead to new physics. Read more Frontier Science Result: Dark Energy Survey Cosmic shadows in the microwave light from the big bang Left: A South Pole...

216

Cosmology for high energy physicists  

SciTech Connect

The standard big bang model of cosmology is presented. Although not perfect, its many successes make it a good starting point for most discussions of cosmology. Places are indicated where well understood laboratory physics is incorporated into the big bang, leading to successful predictions. Much less established aspects of high energy physics and some of the new ideas they have introduced into the field of cosmology are discussed, such as string theory, inflation and monopoles. 49 refs., 5 figs.

Albrecht, A.

1987-11-01T23:59:59.000Z

217

Reactions with radioactive beams and explosive nucleosynthesis  

Science Journals Connector (OSTI)

...depend critically on the pertinent thermonuclear reaction rates involved in a given...novae Novae have been interpreted as thermonuclear runaways on the surface of an accret...critical' mass has been accreted, thermonuclear ignition takes place at the bottom...

1998-01-01T23:59:59.000Z

218

Stable quarks of the 4th family?  

E-Print Network (OSTI)

Existence of metastable quarks of new generation can be embedded into phenomenology of heterotic string together with new long range interaction, which only this new generation possesses. We discuss primordial quark production in the early Universe, their successive cosmological evolution and astrophysical effects, as well as possible production in present or future accelerators. In case of a charge symmetry of 4th generation quarks in Universe, they can be stored in neutral mesons, doubly positively charged baryons, while all the doubly negatively charged "baryons" are combined with He-4 into neutral nucleus-size atom-like states. The existence of all these anomalous stable particles may escape present experimental limits, being close to present and future experimental test. Due to the nuclear binding with He-4 primordial lightest baryons of the 4th generation with charge +1 can also escape the experimental upper limits on anomalous isotopes of hydrogen, being compatible with upper limits on anomalous lithium. While 4th quark hadrons are rare, their presence may be nearly detectable in cosmic rays, muon and neutrino fluxes and cosmic electromagnetic spectra. In case of charge asymmetry, a nontrivial solution for the problem of dark matter (DM) can be provided by excessive (meta)stable anti-up quarks of 4th generation, bound with He-4 in specific nuclear-interacting form of dark matter. Such candidate to DM is surprisingly close to Warm Dark Matter by its role in large scale structure formation. It catalyzes primordial heavy element production in Big Bang Nucleosynthesis and new types of nuclear transformations around us.

K. Belotsky; M. Khlopov; K. Shibaev

2008-06-05T23:59:59.000Z

219

A Cosmological Model without Singularity and Dark Matter  

E-Print Network (OSTI)

According to the cosmological model without singularity, there are s-matter and v-matter which are symmetric and have oppose gravitational masses. In V-breaking s-matter is similar to dark energy to cause expansion of the universe with an acceleration now, and v-matter is composed of v-F-matter and v-W-matter which are symmetric and have the same gravitational masses and forms the world. The ratio of s-matter to v-matter is changeable. Based on the cosmological model, we confirm that big bang nucleosynthesis is not spoiled by that the average energy density of W-matter (mirror matter) is equal to that of F-matter (ordinary matter). According to the present model, there are three sorts of dark matter which are v-W-baryon matter (4/27), unknown v-F-matter (9.5/27) and v-W-matter (9.5/27). Given v-F-baryon matter (4/27) and v-W-baryon matter can cluster and respectively form the visible galaxies and dark galaxies. Unknown v-F-matter and v-W-matter cannot cluster to form any celestial body, loosely distribute in space, are equivalent to cold dark matter, and their compositions are unknown. The number in a bracket is the ratio of the density of a sort of matter to total density of v-matter. The decisive predict is that there are dark celestial bodies and dark galaxies. The energy of F-matter can transform into the energy of W-matter by such a process in which the reaction energy is high enough.

Shi-Hao Chen

2010-01-25T23:59:59.000Z

220

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

E-Print Network (OSTI)

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.

Jens Thomas; Hartmut Schulz

2001-03-18T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

QCD landscape?  

E-Print Network (OSTI)

Just comparing with the scenario that the (3+1)-dimensional "real world" of the Calabi-Yau compactification has a tremendous landscape, we conjecture that a (4+1)-dimensional holographic theory may also hold a landscape of its vacua. Unlike the traditional studies of the AdS/CFT phenomenology where the vacua are always constructive, we discuss the proper holographic vacua and their flux compactification, starting from some general compact Einstein manifolds. The proper vacua should be restricted by (i) a consistent worldsheet theory that possesses the superconformal symmetry, (ii) some definite symmetries to keep/break the corresponding symmetries of the dual field theory, (iii) certain brane/flux configurations to cancel anomalies, and (iv) stabilities. We consider diverse fundamental parameters of the dual field theory, fixed by some special vacuum moduli. In an opposite way, if some field theory such as QCD holds an AdS dual, it may also possesses various fundamental parameters by an "landscape" of its vacuum. Different vacua may be adjacent with each other, and divided by domain walls. If the size of a single vacuum region is smaller than the visible universe, it may be testable. We discuss the consequences of this conjecture in the astrophysical environments, include but not limit to: (i) consistency with the critical energy density of the universe, (ii) the behaviors of cosmic rays, (iii) the stability and abundance of deuterons and other nuclei in the big-bang nucleosynthesis and the star burning scenarios, and (iv) the existence of strange/charm stars.

Cong-Xin Qiu

2009-11-23T23:59:59.000Z

222

bigbangrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

3 3 by K.A. Olive (University of Minnesota) and J.A. Peacock (University of Edinburgh). 21.1. Introduction to Standard Big-Bang Model The observed expansion of the Universe [1,2,3] is a natural (almost inevitable) result of any homogeneous and isotropic cosmological model based on general relativity. However, by itself, the Hubble expansion does not provide sufficient evidence for what we generally refer to as the Big-Bang model of cosmology. While general relativity is in principle capable of describing the cosmology of any given distribution of matter, it is extremely fortunate that our Universe appears to be homogeneous and isotropic on large scales. Together, homogeneity and isotropy allow us to extend the Copernican Principle to the Cosmological Principle, stating that all spatial positions in the Universe are essentially equivalent. The formulation of the Big-Bang

223

Berkeley Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Search 29 Breakthroughs Search 29 Breakthroughs At Berkeley Lab, we've: Discovered sixteen elements. The periodic table would be smaller without Berkeley Lab. Among the Lab's handiwork is an instrumental role in the discovery of technetium-99, which has revolutionized the field of medical imaging. There's also americium, which is widely used in smoke detectors. Identified good and bad cholesterol. The battle against heart disease received a boost in the 1960s when Lab research unveiled the good and bad sides of cholesterol. Today, diagnostic tests that detect both types of cholesterol save lives. Big Bang Confirmed the Big Bang, and discovered dark energy. Lab detectors aboard a NASA satellite revealed the birth of the galaxies in the echoes of the Big Bang. And dark energy - the mysterious something

224

bigbangrpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

1 1 by K.A. Olive (University of Minnesota) and J.A. Peacock (University of Edinburgh). 21.1. Introduction to Standard Big-Bang Model The observed expansion of the Universe [1,2,3] is a natural (almost inevitable) result of any homogeneous and isotropic cosmological model based on general relativity. However, by itself, the Hubble expansion does not provide sufficient evidence for what we generally refer to as the Big-Bang model of cosmology. While general relativity is in principle capable of describing the cosmology of any given distribution of matter, it is extremely fortunate that our Universe appears to be homogeneous and isotropic on large scales. Together, homogeneity and isotropy allow us to extend the Copernican Principle to the Cosmological Principle, stating that all spatial positions in the Universe are essentially equivalent. The formulation of the Big-Bang

225

LOS ALAMOS, N.M., Oct. 31, 2013-Los Alamos National Laboratory scientist  

NLE Websites -- All DOE Office Websites (Extended Search)

Matter, antimatter and surviving the big Matter, antimatter and surviving the big bang is topic of Lab's next Frontiers in Science lecture October 31, 2013 Talk begins at 7 p.m. and open to public LOS ALAMOS, N.M., Oct. 31, 2013-Los Alamos National Laboratory scientist Vincenzo Cirigliano asks the question, How did we survive the big bang? in a series of Frontiers in Science lectures beginning Monday, Nov. 4, in the Duane Smith Auditorium at Los Alamos High School. "Particles and antiparticles were produced in equal numbers in the aftermath of the big bang," according to Cirigliano. "As the primordial soup cooled, they should have completely destroyed each other, leaving behind a universe with no matter. Instead, an - 2 - imbalance of matter over antimatter developed, eventually leading to galaxies and stars

226

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

E-Print Network (OSTI)

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.

Edmund Schluessel

2014-06-17T23:59:59.000Z

227

Nucleosynthesis during the Early History of the Solar System  

Science Journals Connector (OSTI)

......similar situation exists for the isotopes of boron: Blo/Bll is 0.23. These...Spallation reactions give lithium and boron isotope ratios of order unity. Other...played a crucial role in the determination of isotope abundances. In our......

William A. Fowler; Jesse L. Greenstein; Fred Hoyle

1962-02-01T23:59:59.000Z

228

Neutrino-induced nucleosynthesis in core-collapse supernovae  

SciTech Connect

Almost all of the 3{center dot}10{sup 53} ergs liberated in a core collapse supernova is radiated as neutrinos by the cooling neutron star. The neutrinos can excite nuclei in the mantle of the star by their neutral and charged current reactions. The resulting spallation reactions are an important nuleosynthesis mechanism that may be responsible for the galactic abundances of {sup 7}Li, {sup 11}B, {sup 19}F, {sup 138}La, {sup 180}Ta, and number of other nuclei. 10 refs., 1 fig., 1 tab.

Hartmann, D.H. (Lawrence Livermore National Lab., CA (USA)); Haxton, W.C. (Washington Univ., Seattle, WA (USA). Dept. of Physics); Hoffman, R.D. (California Univ., Santa Cruz, CA (USA). Board of Studies in Astronomy and Astrophysics); Woosley, S.E. (Lawrence Livermore National Lab., CA (USA) California Univ., Santa Cruz, CA (USA). Board of Studies in Astronomy and Astrophysics)

1990-01-01T23:59:59.000Z

229

Probing AGB nucleosynthesis via accurate Planetary Nebula abundances  

E-Print Network (OSTI)

The elemental abundances of ten planetary nebulae, derived with high accuracy including ISO and IUE spectra, are analysed with the aid of synthetic evolutionary models for the TP-AGB phase. Model prescriptions are varied until we achieve the simultaneous reproduction of all elemental features, which allows placing important constraints on the characteristic masses and nucleosynthetic processes experienced by the stellar progenitors. First of all, it is possible to separate the sample into two groups of PNe, one indicating the occurrence of only the third dredge-up during the TP-AGB phase, and the other showing also the chemical signature of hot-bottom burning. The former group is reproduced by stellar models with variable molecular opacities (see Marigo 2002), adopting initial solar metallicity, and typical efficiency of the third dredge-up 0.3-0.4. The latter group of PNe, with extremely high He content 0.15 4.5-5.0 Mo) with LMC composition have suffered a number of very efficient, carbon-poor, dredge-up eve...

Marigo, P; Pottasch, S R; Tielens, A G G M; Wesselius, P R

2003-01-01T23:59:59.000Z

230

National Aeronautics and Space Administration Science Program  

E-Print Network (OSTI)

that powered the Big Bang, and the dark energy propelling the cosmic expansion today. Forward Technology Enables Discovery 7 Sustainingthe Vision 8 Engaging Students and the Public Appendices A. Science Einstein Probe missions is dedicated to specific studies of black hole discovery, the cosmic inflation

231

NEWS:  

Science Journals Connector (OSTI)

...October 2006 news News News in Brief A&G October 2006 Vol. 47 5.5 News ShadowsonBigBang Galaxy clusters should cast shadows on the Cosmic Microwave Background, according to Rashid Sunyaev and Yakov Zel'dovich in 1969, because they are younger......

News in Brief

2006-10-01T23:59:59.000Z

232

Magnetic Bianchi type II string cosmological model in loop quantum cosmology  

E-Print Network (OSTI)

The loop quantum cosmology of the Bianchi type II string cosmological model in the presence of a homogeneous magnetic field is studied. We present the effective equations which provide modifications to the classical equations of motion due to quantum effects. The numerical simulations confirm that the big bang singularity is resolved by quantum gravity effects.

Victor Rikhvitsky; Bijan Saha; Mihai Visinescu

2013-12-09T23:59:59.000Z

233

30 Years of Hot Quark Soup What have we learned about  

E-Print Network (OSTI)

that superdense matter (found in neutron-star cores, exploding black holes, and the early big-bang universe) and deconfined (unbound gluons). QCD Confinement/deconfinement phase transition: = condensation of electric flux 3 g 4 g 5 g 6 (ln(1/g)+0.7) lattice data Numerical lattice data com- pared with successi

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

234

Why is it so easy to underestimate systematic errors when measuring G?  

Science Journals Connector (OSTI)

...inflationary period just after the Big Bang. This stunning result...discovery, if true, might have on Big G. Five years ago Galli et...wide variety of astronomical data, including a striking set of...DF . 2004 Analogies between electricity and gravity. Metrologia 41...

2014-01-01T23:59:59.000Z

235

Feynman Clocks, Causal Networks, and The Origin of Hierarchical 'Arrows of Time' in Complex Systems. Part 1: 'Conjectures'  

E-Print Network (OSTI)

A theory of time as 'information' is outlined using new tools such as Feynman Clocks (FCs), Collective Excitation Networks (CENs), Sequential Excitation Networks (SENs), and Plateaus of Complexity (POCs). Applications of this approach range from the Big Bang to the emergence of 'consciousness'.

Scott Hitchcock

2001-02-06T23:59:59.000Z

236

Climbing the cosmological distance ladder  

Science Journals Connector (OSTI)

......knowledge of cosmological distance - towards redshift 1000! Humankind's efforts to measure the distances of the planets, stars...the epoch when matter and radiation finally decoupled at the end of the hot Big Bang phase. Apparently we have reached a precision......

Michael Rowan-Robinson

2008-06-01T23:59:59.000Z

237

Supersymmetry and Inflation  

E-Print Network (OSTI)

Inflation is a promising solution to many problems of the standard Big-Bang cosmology. Nevertheless, inflationary models have proved less compelling. In this chapter, we discuss why supersymmetry has led to more natural models of inflation. We pay particular attention to multifield models, both with a high and a low Hubble parameter.

Lisa Randall

1997-11-25T23:59:59.000Z

238

Prolegomena to Any Future Physics-Based Metaphysics  

E-Print Network (OSTI)

sometimes appeal to physics to provide support for the hypothesis that God exists. More generally and Big-Bang-based arguments in favor of the existence of God. I am not arguing that physics theory (from, for example, the two-slit experiment) suggests that a particle can be in a superposition

Mojzsis, Stephen J.

239

C. R. Geoscience 335 (2003) 6578 Geodynamics / Godynamique  

E-Print Network (OSTI)

(evolution's `Big Bang') remains an unsolved puzzle in Earth Science. The Vendian­Cambrian interval these deposits back to the Tropics, where they gradually warmed and were subjected to regional-scale thermohaline-induced pulses of global warming when they erupt. Temperature correlates powerfully with biodiversity

240

[The Story of the Solar System] The Solar System -II  

E-Print Network (OSTI)

-TauriPhase SolarNebula #12;Giant Molecular Cloud o About 50-100 light years across o more than a million times[The Story of the Solar System] The Solar System - II Alexei Gilchrist #12;Some resources o Section of the Solar System, M Garlick, (Cambridge Uni. Press, 2002) #12;Timeline Today Big Bang Earliest Fossils Birth

Wardle, Mark

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Waves in Nature, Lasers to Tsumanis and Beyond  

ScienceCinema (OSTI)

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

LLNL - University of California Television

2009-09-01T23:59:59.000Z

242

Cosmology with Type Ia The Sloan Digital Sky Survey  

E-Print Network (OSTI)

- Present) - Cosmic Microwave Background - Supernovae and Dark Energy - Galaxy Clustering SDSS Supernova% of recollapse density · Favors Dark Energy #12;M51: June 2005 M51: July 2005 #12;#12;· Easy to identify · Geometry is flat · ~70% Dark Energy · ~30% Matter · There was a Big Bang · There will be a Big Chill #12

Cinabro, David

243

Behind the mask of the LHC  

Science Journals Connector (OSTI)

... and indeed all scientists, should rejoice that the advent of the Large Hadron Collider (LHC) has become a significant cultural event. Dubbed the 'Big Bang machine', the ... jamboree. The most obvious is the temptation for hype and false promises about what the LHC will achieve, as though all the secrets of creation are about to come tumbling ...

Philip Ball

2008-07-03T23:59:59.000Z

244

29April2011JohnLearnedatIceCubeDedication1 IceCube Dedication Symposium, Madison, Wisconsin  

E-Print Network (OSTI)

(Cosmic Rays) Sun Supernovae (star collapse) SN 1987A Bulk Earth (U/Th Radioactivity) Big Bang (hereLearnedatIceCubeDedication6 · No electric charge. · Little or no electric/magnetic dipole moment. · Essentially point interaction states (" oscillations"). · Three mass states explains all accepted data, but room for new things

Learned, John

245

Vol.4 No.9 September 2008 www.nature.com/naturephysics Things ain't what they used to be. No  

E-Print Network (OSTI)

, as it was called then, was created in 1925 from the merger of Western Electric Research Laboratories and part-over from a receiver system built at the lab for the Echo satellite5 . But their data were dogged was in fact the signal of the Big Bang, now dissipated after billions of years to a black-body temperature

Loss, Daniel

246

22July2012JohnLearnedatUlan-Ude1 23 July 2012  

E-Print Network (OSTI)

Supernovae (star collapse) SN 1987A ü Big Bang (here 330 /cm3) Indirect Evidence Bulk Earth (Geonus: ULearnedatUlan-Ude7 · No electric charge. · Little or no electric/magnetic dipole moment. · Essentially point interaction states (" oscillations"). · Three mass states explains all accepted data, but room for new things

Learned, John

247

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

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.

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

2008-04-01T23:59:59.000Z

248

NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: FINAL MAPS AND RESULTS  

SciTech Connect

We present the final nine-year maps and basic results from the Wilkinson Microwave Anisotropy Probe (WMAP) mission. The full nine-year analysis of the time-ordered data provides updated characterizations and calibrations of the experiment. We also provide new nine-year full sky temperature maps that were processed to reduce the asymmetry of the effective beams. Temperature and polarization sky maps are examined to separate cosmic microwave background (CMB) anisotropy from foreground emission, and both types of signals are analyzed in detail. We provide new point source catalogs as well as new diffuse and point source foreground masks. An updated template-removal process is used for cosmological analysis; new foreground fits are performed, and new foreground-reduced CMB maps are presented. We now implement an optimal C {sup –1} weighting to compute the temperature angular power spectrum. The WMAP mission has resulted in a highly constrained ?CDM cosmological model with precise and accurate parameters in agreement with a host of other cosmological measurements. When WMAP data are combined with finer scale CMB, baryon acoustic oscillation, and Hubble constant measurements, we find that big bang nucleosynthesis is well supported and there is no compelling evidence for a non-standard number of neutrino species (N {sub eff} = 3.84 ± 0.40). The model fit also implies that the age of the universe is t {sub 0} = 13.772 ± 0.059 Gyr, and the fit Hubble constant is H {sub 0} = 69.32 ± 0.80 km s{sup –1} Mpc{sup –1}. Inflation is also supported: the fluctuations are adiabatic, with Gaussian random phases; the detection of a deviation of the scalar spectral index from unity, reported earlier by the WMAP team, now has high statistical significance (n{sub s} = 0.9608 ± 0.0080); and the universe is close to flat/Euclidean (?{sub k} = -0.0027{sup +0.0039}{sub -0.0038}). Overall, the WMAP mission has resulted in a reduction of the cosmological parameter volume by a factor of 68,000 for the standard six-parameter ?CDM model, based on CMB data alone. For a model including tensors, the allowed seven-parameter volume has been reduced by a factor 117,000. Other cosmological observations are in accord with the CMB predictions, and the combined data reduces the cosmological parameter volume even further. With no significant anomalies and an adequate goodness of fit, the inflationary flat ?CDM model and its precise and accurate parameters rooted in WMAP data stands as the standard model of cosmology.

Bennett, C. L.; Larson, D.; Weiland, J. L. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686 (United States); Jarosik, N.; Page, L. [Department of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544-0708 (United States); Hinshaw, G.; Halpern, M. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Odegard, N.; Hill, R. S. [ADNET Systems, Inc., 7515 Mission Drive, Suite A100, Lanham, MD 20706 (United States); Smith, K. M. [Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 2Y5 (Canada); Gold, B. [School of Physics and Astronomy, University of Minnesota, 116 Church Street S.E., Minneapolis, MN 55455 (United States); Komatsu, E. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild Str. 1, D-85741 Garching (Germany); Nolta, M. R. [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada); Spergel, D. N. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544-1001 (United States); Wollack, E.; Kogut, A. [Code 665, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Dunkley, J. [Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Limon, M. [Columbia Astrophysics Laboratory, 550 West 120th Street, Mail Code 5247, New York, NY 10027-6902 (United States); Meyer, S. S. [Departments of Astrophysics and Physics, KICP and EFI, University of Chicago, Chicago, IL 60637 (United States); Tucker, G. S., E-mail: cbennett@jhu.edu [Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912-1843 (United States); and others

2013-10-01T23:59:59.000Z

249

Molecular and anatomic imaging of bombesin BB2 receptor subtype expressing tumor models  

Science Journals Connector (OSTI)

...N3S-5-Ava-BBN[7-14]NH2 and DOTA-8-Aoc-BBN[7-14]NH2 were synthesized using...99mTc-N3S-5-Ava-BBN[7-14]NH2 and 111In-DOTA-8-Aoc-BBN[7-14]NH2 were prepared and purified...successful in visualizing 111In-DOTA-8-Aoc-BBN[7-14]NH2 uptake in breast and...

Timothy J. Hoffman; Said D. Figueroa; Christopher T. Winkelmann; Jered C. Garrison; Lixin Ma; Tammy L. Rold; Gary L. Sieckman; Charles J. Smith; Wynn A. Volkert

2006-04-15T23:59:59.000Z

250

Jefferson Lab Science Series - The Origin of the Elements  

NLE Websites -- All DOE Office Websites (Extended Search)

You Already Know This Physics! You Already Know This Physics! Previous Video (You Already Know This Physics!) Science Series Video Archive Next Video (Guesstimating the Environment) Guesstimating the Environment The Origin of the Elements Dr. Edward Murphy - University of Virginia, Department of Astronomy November 13, 2012 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,

251

South Pole Telescope helps Argonne scientists study earliest ages of the  

NLE Websites -- All DOE Office Websites (Extended Search)

Related Content Related Content Employee Spotlight: Clarence Chang South Pole Telescope helps Argonne scientists study earliest ages of the universe By Louise Lerner * October 28, 2013 Tweet EmailPrint For physicist Clarence Chang at the U.S. Department of Energy's (DOE) Argonne National Laboratory, looking backward in time to the earliest ages of the universe is all in a day's work. Chang helped design and operate part of the South Pole Telescope, a project that aims a giant telescope at the night sky to track tiny bits of radiation that are still traveling across the universe from the period just after it was born. "Basically, what we're looking at is the afterglow light of the Big Bang," Chang said. In the wake of the Big Bang, all the matter in the universe was just hot,

252

Symposium on the Nature of Science—Rocky Kolb  

NLE Websites -- All DOE Office Websites (Extended Search)

FIRST SECOND IN THE LIFE OF THE UNIVERSE FIRST SECOND IN THE LIFE OF THE UNIVERSE Rocky Kolb Watch the talk (Running time 51:09) Video in Frame Detached Video Some users have reported problems with the "Video in Frame" option. If you have problems, please try the "Detached Video" option. Requires RealPlayer 7.0 or higher. Get RealPlayer Thirteen billion years ago our universe started with a bang. Today we are gathering the fossil evidence of the very earliest moments of the universe. Our picture of the very beginning of the universe is still incomplete, with outstanding questions like: What powered the big bang? What is the dark matter that binds together the universe? What is the dark energy that thrusts apart the universe? Are there hidden spacetime dimensions? What was before the big bang?

253

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

E-Print Network (OSTI)

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

Aharon Davidson; Tomer Ygael

2014-10-13T23:59:59.000Z

254

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

E-Print Network (OSTI)

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

Davidson, Aharon

2014-01-01T23:59:59.000Z

255

Does the universe obey the energy conservation law by a constant mass or an increasing mass with radius during its evolution?  

E-Print Network (OSTI)

How the energy conservation law is obeyed by the universe during its evolution is an important but not yet unanimously resolved question. Does the universe have a constant mass during its evolution or has its mass been increasing with its radius? Here, we evaluate the two contending propositions within the context of the Friedmann equations and the standard big bang theory. We find that though both propositions appeal to the Friedmann equations for validity, an increasing mass with increasing radius is more in harmony with the thermal history of the big bang model. In addition, temperature and flatness problems that plague the constant mass proposal are mitigated by the increasing mass with radius proposal. We conclude that the universe has been increasing in mass and radius in obedience to the energy conservation law.

Akinbo Ojo

2008-10-09T23:59:59.000Z

256

Matter Under Extreme Conditions: The Early Years  

E-Print Network (OSTI)

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...

Keeler, R Norris

2010-01-01T23:59:59.000Z

257

The Origin of the Elements  

ScienceCinema (OSTI)

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.

Murphy, Edward

2014-08-06T23:59:59.000Z

258

Loop quantum cosmology in 2+1 dimension  

E-Print Network (OSTI)

As a first step to generalize the structure of loop quantum cosmology to the theories with the spacetime dimension other than four, the isotropic model of loop quantum cosmology in 2+1 dimension is studied in this paper. We find that the classical big bang singularity is again replaced by a quantum bounce in the model. The similarities and differences between the 2+1 dimensional model and the 3+1 dimensional one are also discussed.

Xiangdong Zhang

2014-11-19T23:59:59.000Z

259

Gravitational Entropy and the Second Law of Thermodynamics  

E-Print Network (OSTI)

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\

Moffat, J W

2014-01-01T23:59:59.000Z

260

Cosmology, Thermodynamics and Matter Creation  

E-Print Network (OSTI)

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.

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

2007-08-24T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Phenomenology of the Invisible Universe  

Science Journals Connector (OSTI)

Cosmology is operating now on a well established and tightly constraining empirical basis. The relativistic ?CDM hot big bang theory is consistent with all the present tests; it has become the benchmark. But the many open issues in this subject make it reasonable to expect that a more accurate cosmology will have more interesting physics in the invisible sector of the universe and maybe also in the visible part.

P. J. E. Peebles

2010-01-01T23:59:59.000Z

262

Inflation and the Higgs Scalar  

E-Print Network (OSTI)

This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A quartic scalar potential model of inflation is evaluated which provides the solution of those problems and makes predictions which will soon be definitively tested. The possibility that the recently discovered fundamental Higgs scalar field drives inflation is explored.

Dan Green

2014-12-05T23:59:59.000Z

263

Evaluation of the Pharmacokinetic Effects of Various Linking Group Using the 111In-DOTA-X-BBN(7?14)NH2 Structural Paradigm in a Prostate Cancer Model  

Science Journals Connector (OSTI)

For PC-3 tumor-bearing SCID mice, the tumor uptake was found to be 6.66 ± 2.00, 6.21 ± 1.57, 6.36 ± 1.60, 4.46 ± 0.81, and 7.76 ± 1.19 %ID/g for the 8-AOC, 8-ADS, AMBA, Gly-AMBA, and Gly-AM2BA radioconjugates, respectively, at 15 min postinjection. ... The natIn-labeled conjugates had IC50 values of 0.51 ± 0.05, 0.7 ± 0.1, 1.13 ± 0.07, 1.88 ± 0.06, 3.2 ± 0.3, and 6.2 ± 0.3 nM for the 8-AOC, Gly-AM2BA, AMBA, Gly-AMBA, 8-ADS, and 5-AOS, respectively. ...

Jered C. Garrison; Tammy L. Rold; Gary L. Sieckman; Farah Naz; Samantha V. Sublett; Said Daibes Figueroa; Wynn A. Volkert; Timothy J. Hoffman

2008-08-20T23:59:59.000Z

264

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

E-Print Network (OSTI)

. Roeder,2 E. Simmons,2 G. Tabacaru,2,? R. E. Tribble,2 P. J. Woods,4 and J. ?Aysto?1 1Department of Physics, University of Jyva?skyla?, P.O. Box 35 (YFL), FI-40014 Finland 2Cyclotron Institute, Texas A&M University, College Station, Texas 77843-3366, USA...?ja?rvi for their valuable comments. This work has been supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2006-2011 (Project No. 213503, Nuclear and Accelerator Based Physics Programme at JYFL) and by the US Department of Energy under...

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

265

Nucleosynthesis at the proton drip line a challenge for nuclear physics  

E-Print Network (OSTI)

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

Rauscher, Thomas

266

We investigate the nucleosynthesis in combustion events in stellar evolution. These are  

E-Print Network (OSTI)

predicted by this mixing-length theory based model is by far unable to account for the significantly non-solar abundance distribution observed in this shell- flash star (elements like RB, Sr and Y are overabundant

Herwig, Falk

267

Solar abundance of {sup 176}Lu and s-process nucleosynthesis  

SciTech Connect

The isotopic composition of lutetium has been measured with high precision using a thermal ionization mass spectrometer whose linearity was verified by measuring an isotopically certified reference material for potassium prepared by the National Institute of Standards and Technology (NIST 985). The abundance sensitivity of the mass spectrometer for the measured ion beams of Lu{sup +} was examined to ensure the absence of tailing effects and interfering ion beams. The isotope fractionation of the measured {sup 176}Lu/{sup 175}Lu ratio was estimated with reference to the isotope fractionation of ytterbium (whose isotopes are in the same mass region as lutetium), which was recently measured in this laboratory using gravimetrically prepared solutions of the enriched isotopes {sup 171}Yb and {sup 176}Yb. This is the first reported publication in which the measured isotope ratio of Lu has been corrected for isotope fractionation. An accurate determination of the abundance of {sup 176}Lu is required because of the importance of this isotope in cosmochronometry, cosmothermometry, and s-process branching studies. An accurate abundance of {sup 176}Lu is also required as it is the parent nuclide of the {sup 176}Lu/{sup 176}Hf geochronometer. The measured isotopic composition of Lu, corrected for isotope fractionation, is {sup 176}Lu/{sup 175}Lu = 0.026680 {+-} 0.000013, which gives isotope abundances for {sup 175}Lu of 97.4013 {+-} 0.0012% and of {sup 176}Lu of 2.5987 {+-} 0.0012%. The isotope abundances and relative atomic masses of the two isotopes give an atomic weight of 174.9668 {+-} 0.0001, which is in good agreement with the present Standard Atomic Weight A{sub r}(Lu) = 174.967 {+-} 0.001, but with improved accuracy. An accurate assessment of the {sup 176}Lu/{sup 175}Lu ratio is important in order to calculate the Solar System abundances of {sup 175}Lu and {sup 176}Lu for astrophysical evaluations. The experimentally determined Solar System abundances for {sup 175}Lu and {sup 176}Lu of 0.0347918 {+-} 0.0000004 and 0.0009282 {+-} 0.0000004, respectively (as compared to silicon equals 10{sup 6} atoms), should now be used for these purposes. This determination of the isotopic composition of Lu also demonstrates that the presently accepted half-life of {sup 176}Lu needs to be reevaluated.

Laeter, J.R. de; Bukilic, N. [Department of Applied Physics, Curtin University of Technology, GPO Box U1987, Perth, Western Australia, 6845 (Australia)

2006-04-15T23:59:59.000Z

268

Shedding New Light on Exploding Stars: Terascale Simulations of Nuetrino-Dreiven Supernovas and Their Nucleosynthesis  

SciTech Connect

Project Abstract This project was a continuation of work begun under a subcontract issued off of TSI-DOE Grant 1528746, awarded to the University of Illinois Urbana-Champaign. Dr. Anthony Mezzacappa is the Principal Investigator on the Illinois award. A separate award was issued to Santa Clara University to continue the collaboration during the time period May 2003 ? 2004. Smolarski continued to work on preconditioner technology and its interface with various iterative methods. He worked primarily with F. Dough Swesty (SUNY-Stony Brook) in continuing software development started in the 2002-03 academic year. Special attention was paid to the development and testing of difference sparse approximate inverse preconditioners and their use in the solution of linear systems arising from radiation transport equations. The target was a high performance platform on which efficient implementation is a critical component of the overall effort. Smolarski also focused on the integration of the adaptive iterative algorithm, Chebycode, developed by Tom Manteuffel and Steve Ashby and adapted by Ryan Szypowski for parallel platforms, into the radiation transport code being developed at SUNY-Stony Brook.

Dennis C. Smolarski, S.J.

2004-11-10T23:59:59.000Z

269

Cross-section measurement of the $^{130}$Ba(p,$?$)$^{131}$La reaction for $?$-process nucleosynthesis  

E-Print Network (OSTI)

A measurement of total cross-section values of the $^{130}$Ba(p,$\\gamma$)$^{131}$La reaction at low proton energies allows a stringent test of statistical model predictions with different proton+nucleus optical model potentials. Since no experimental data are available for proton-capture reactions in this mass region around A~$\\approx$~130, this measurement can be an important input to test the global applicability of proton+nucleus optical model potentials. The total reaction cross-section values were measured by means of the activation method. After the irradiation with protons, the reaction yield was determined by use of $\\gamma$-ray spectroscopy using two clover-type high-purity germanium detectors. In total, cross-section values for eight different proton energies could be determined in the energy range between 3.6 MeV $\\leq E_p \\leq$ 5.0 MeV, thus, inside the astrophysically relevant energy region. The measured cross-section values were compared to Hauser-Feshbach calculations using the statistical model codes TALYS and SMARAGD with different proton+nucleus optical model potentials. With the semi-microscopic JLM proton+nucleus optical model potential used in the SMARAGD code, the absolute cross-section values are reproduced well, but the energy dependence is too steep at the lowest energies. The best description is given by a TALYS calculation using the semi-microscopic Bauge proton+nucleus optical model potential using a constant renormalization factor.

L. Netterdon; A. Endres; G. G. Kiss; J. Mayer; T. Rauscher; P. Scholz; K. Sonnabend; Zs. Török; A. Zilges

2014-09-27T23:59:59.000Z

270

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

SciTech Connect

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.

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

271

Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the  

E-Print Network (OSTI)

evolution (which is discussed in detail in section IV). c fl 1995 American Institute of Physics 1 #12; 2 A Basic Evolution at 1 Solar Mass We make the usual assumption that a star reaches the zero­age main se. Core H­burning occurs radiatively, and the central temperature and density grow in response

Lattanzio, John

272

The r-process nucleosynthesis during the decompression of neutronised matter  

SciTech Connect

The rapid neutron-capture process, or r-process, is known to be of fundamental importance for explaining the origin of approximately half of the A>60 stable nuclei observed in nature. In recent years nuclear astrophysicists have developed more and more sophisticated r-process models, eagerly trying to add new astrophysical or nuclear physics ingredients to explain the solar system composition in a satisfactory way.We show here that the decompression of the neutron star matter may provide suitable conditions for a robust r-processing. After decompression, the inner crust material gives rise to an abundance distribution for A>130 nuclei similar to the one observed in the solar system. Similarly, the outer crust if heated at a temperature of about 8 10{sup 9} K before decompression is made of exotic neutron-rich nuclei with a mass distribution close to the 80{<=}A{<=}130 solar one. During the decompression, the free neutrons (initially liberated by the high temperatures) are re-captured leading to a final pattern similar to the solar system distribution.

Goriely, S.; Chamel, N. [IAA-ULB, Campus de la Plaine, CP 226, 1050 Brussels (Belgium); Pearson, J. M. [Dept. de Physique, Universite de Montreal, Montreal (Quebec), H3C 3J7 (Canada)

2011-10-28T23:59:59.000Z

273

Targeting BB2 receptor expression in prostate cancer using promethium-149 labeled peptides  

Science Journals Connector (OSTI)

...expressed on human PC-3 cells. DOTA-8-Aoc-BBN[7-14]NH2 (BBN[7-14]NH2...BB2 receptor subtype. 149Pm-DOTA-8-Aoc-BBN[7-14]NH2 was prepared by dissolving...incubated at 80C for 1 hr. 149Pm-DOTA-8-Aoc-BBN[7-14]NH2 was obtained in 98...

Tammy L. Rold; Jered C. Garrison; Gary L. Sieckman; Serena N. Carter; Nicholas R. Bell; Cathy S. Cutler; Charles J. Smith; Timothy J. Hoffman

2006-04-15T23:59:59.000Z

274

BB2 receptor targeted radiotherapy combined with chemotherapy for the treatment of pre-clinical xenograft models of breast cancer  

Science Journals Connector (OSTI)

...with 5X106 cells per flank. DOTA-8-AOC-BBN(7-14)NH2 was synthesized via...nanomole affinity. Lu-177-DOTA-8-AOC-BBN(7-14)NH2 was prepared and purified...sensitizer. Combination Lu-177-DOTA-8-AOC-BBN(7-14)NH2/DOC studies were...

Timothy J. Hoffman; Tammy L. Rold; Gary L. Sieckman; Charles J. Smith; Wynn A. Volkert; Michael C. Perry

2006-04-15T23:59:59.000Z

275

Abstract 3264: Preclinical multi-modal therapy of metastatic androgen independent prostate cancer using docetaxel, capecitabine, and a Lu-177-BB2r targeting peptide  

Science Journals Connector (OSTI)

...demonstrated that 177Lu-177-DOTA-8-AOC-BBN(7-14)NH2, when administered...related to the use of 177Lu-177-DOTA-8-AOC-BBN(7-14)NH2 and chemotherapy for...SCID mouse model. Methods: DOTA-8-AOC-BBN(7-14)NH2 was synthesized in...

Christopher A. Manuel; Tammy L. Rold; Gary L. Sieckman; Ashley F. Szczodroski; Timothy J. Hoffman

2011-07-12T23:59:59.000Z

276

Physics | More Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics Physics ORNL Physics More Science Home | Science & Discovery | More Science | Physics SHARE Physics Bottom view of the 25 million volt tandem electrostatic accelerator of the Holifield Heavy Ion Research Facility. Physics researchers at ORNL seek to answer fascinating questions about our Universe: What are the nuclear reactions that drive stellar explosions? How does nuclear matter organize itself? What are the properties of nuclear interactions? Why is there more matter than antimatter in the universe? Is the neutrino its own antiparticle? What are the properties of matter that existed just after the Big Bang? Our research staff address these questions by developing experimental techniques and detector systems, performing experiments at national and

277

hepreqrev.pptx  

NLE Websites -- All DOE Office Websites (Extended Search)

Microwave Background Microwave Background Data Analysis Julian Borrill Computational Cosmology Center, LBNL Space Sciences Laboratory, UCB A History Of The Universe Planck CMB Science * Past: - Existence => evidence of Big Bang over Steady State - Temperature anisotropies => fundamental parameters of cosmology, complementary constraints (SN1a) * Present: - Temperature & E-mode polarization anisotropies => precision cosmology, complementary constraints (DE) * Future: - B-mode polarization anisotropies => measurement of lensing potential, evidence of & constraints on Inflation 2 Nobel Prizes awarded, 1 supported, 1 anticipated! The CMB Data Challenge * Extracting fainter signals (polarization, high resolution) from the data requires: - larger data volumes to provide higher signal-to-noise.

278

Distinguished Lecturers Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Videos Videos Lawrence Berkeley National Laboratory Environmental Energy Technologies Division Distinguished Lecture Series Environmental Energy Technologies Division Distinguished Lecture Series Videos Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon, October 22, 2012 Climate Change Hits Home: Impacts on the Built Environment and Health John Spengler, June 18, 2012 High Comfort-Low Impact, From Buildings to Cities Matthias Schuler, April 30, 2012 Emissions Trading and Climate Finance: Is 2012 the Dead End or the Crossroads? Marc Stuart, January 27, 2012 Advances in Global Climate Modeling for Scientific Understanding and Predictability V. Ramaswamy, October 7, 2011 How is Building Energy Use Related to Occupant Behaviors and Building Usage

279

Distinguished Lecturers Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Past Seminars Past Seminars Lawrence Berkeley National Laboratory Environmental Energy Technologies Division Distinguished Lecture Series Environmental Energy Technologies Division Distinguished Lecture Series Andrew Hargadon October 22, 2012 Long Fuse, Big Bang: Thomas Edison, Electricity, and the Locus of Innovation Andrew Hargadon Charles J. Soderquist Chair in Entrepreneurship Professor of Technology Management at the Graduate School of Management University of California, Davis John Spengler June 18, 2012 Climate Change Hits Home: Impacts on the Built Environment and Health John Spengler Akira Yamaguchi Professor of Environmental Health & Human Habitation Harvard School of Public Health and Director of the Sustainability and Environmental Management Program Harvard Extension School

280

Nuclear Fusion Drives Present-Day Accelerated Cosmic Expansion  

SciTech Connect

The widely accepted model of our cosmos is that it began from a Big Bang event some 13.7 billion years ago from a single point source. From a twin universe perspective, the standard stellar model of nuclear fusion can account for the Dark Energy needed to explain the mechanism for our present-day accelerated expansion. The same theories can also be used to account for the rapid inflationary expansion at the earliest time of creation, and predict the future cosmic expansion rate.

Ying, Leong [Princeton Gamma-Tech Instruments, 303C College Road East, Princeton, NJ 07030 (United States)

2010-09-30T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Quintessence and phantom cosmology with nonminimal derivative coupling  

SciTech Connect

We investigate cosmological scenarios with a nonminimal derivative coupling between the scalar field and the curvature, examining both the quintessence and the phantom cases in zero and constant potentials. In general, we find that the universe transits from one de Sitter solution to another, determined by the coupling parameter. Furthermore, according to the parameter choices and without the need for matter, we can obtain a big bang, an expanding universe with no beginning, a cosmological turnaround, an eternally contracting universe, a big crunch, a big rip avoidance, and a cosmological bounce. This variety of behaviors reveals the capabilities of the present scenario.

Saridakis, Emmanuel N. [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Sushkov, Sergey V. [Department of General Relativity and Gravitation, Kazan State University, Kremlevskaya Street 18, Kazan 420008 (Russian Federation); Department of Mathematics, Tatar State University of Humanities and Education, Tatarstan Street 2, Kazan 420021 (Russian Federation)

2010-04-15T23:59:59.000Z

282

Designing Cyclic Universe Models  

E-Print Network (OSTI)

Recent advances in understanding the propagation of perturbations through the transition from big crunch to big bang (esp. Tolley et al. hep-th/0306109) make it possible for the first time to consider the full set of phenomenological constraints on the scalar field potential in cyclic models of the universe. We show that cyclic models require a comparable degree of tuning to that needed for inflationary models. The constraints are reduced to a set of simple design rules including "fast-roll" parameters analogous to the "slow-roll" parameters in inflation.

Justin Khoury; Paul J. Steinhardt; Neil Turok

2003-07-15T23:59:59.000Z

283

Density Perturbations in the Ekpyrotic Scenario  

E-Print Network (OSTI)

We study the generation of density perturbations in the ekpyrotic scenario for the early universe, including gravitational backreaction. We expose interesting subtleties that apply to both inflationary and ekpyrotic models. Our analysis includes a detailed proposal of how the perturbations generated in a contracting phase may be matched across a `bounce' to those in an expanding hot big bang phase. For the physical conditions relevant to the ekpyrotic scenario, we re-obtain our earlier result of a nearly scale-invariant spectrum of energy density perturbations. We find that the perturbation amplitude is typically small, as desired to match observation.

Justin Khoury; Burt A. Ovrut; Paul J. Steinhardt; Neil Turok

2001-09-06T23:59:59.000Z

284

Russian Military and Security Forces: A Postulated Reaction to a Nuclear Detonation  

SciTech Connect

In this paper, we will examine how Russia's military and security forces might react to the detonation of a 10-kiloton nuclear weapon placed next to the walls surrounding the Kremlin. At the time of this 'big bang,' Putin is situated outside Moscow and survives the explosion. No one claims responsibility for the detonation. No other information is known. Numerous variables will determine how events ultimately unfold and how the military and security forces will respond. Prior to examining these variables in greater detail, it is imperative to elucidate first what we mean by Russia's military and security forces.

Ball, D

2005-04-29T23:59:59.000Z

285

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

E-Print Network (OSTI)

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... whether this was due to flat-fielding errors by constructing a corrective flat-field from our pipelined images. All 25 ACS images were scaled to the same sky level, and this stack was median filtered before the small-scale structure was removed...

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

2014-07-02T23:59:59.000Z

286

Constraining supersymmetric SO(10) models through cosmology  

Science Journals Connector (OSTI)

We study the impact of the symmetry-breaking patterns from supersymmetric SO(10) down to the standard model on the standard big-bang cosmology through the formation of topological defects. None of the models is consistent with the standard cosmology without invoking any mechanism to solve the monopole problem. For this purpose, we use a hybrid false vacuum inflationary scenario. Only two symmetry-breaking patterns are consistent with these topological considerations and with the actual data on the proton lifetime. © 1995 The American Physical Society.

Rachel Jeannerot and Anne-Christine Davis

1995-12-15T23:59:59.000Z

287

What the inflaton might tell us about RHIC/LHC  

E-Print Network (OSTI)

Topical phenomena in high-energy physics related to collision experiments of heavy nuclei ("Little Bang") and early universe cosmology ("Big Bang") involve far-from-equilibrium dynamics described by quantum field theory. One example concerns the role of plasma instabilities for the process of thermalization in heavy-ion collisions. The reheating of the early universe after inflation may exhibit rather similar phenomena following a tachyonic or parametric resonance instability. Certain universal aspects associated to nonthermal fixed points even quantitatively agree, and considering these phenomena from a common perspective can be fruitful.

J. Berges

2008-11-26T23:59:59.000Z

288

Planck Surveyor On Its Way to Orbit  

ScienceCinema (OSTI)

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.

Borrill, Julian

2013-05-29T23:59:59.000Z

289

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

E-Print Network (OSTI)

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.

Raymond Y. Chiao

2007-02-19T23:59:59.000Z

290

A Simple Cosmological Model with Decreasing Light Speed  

E-Print Network (OSTI)

An alternative model describing the dynamics of a flat Universe without cosmological constant and allowing a gradual change of c with time is proposed. New relationships of redshift vs. distance and cosmic background radiation temperature are given. Values for the Universal radius, matter density, Hubble parameter, light deceleration, cosmic age and recombination time are obtained. Distant SNeIa faintness is explained within this decelerating, matter-dominated Universe without invoking dark energy. Horizon, flatness and other problems of standard Big Bang cosmology are solved without the need of inflation. The top speed of any signal, force, particle or wave at any time is limited by the expansion speed of the Universe itself.

Juan Casado Gimenez

2003-10-07T23:59:59.000Z

291

Massive star evolution and nucleosynthesis: Lower end of Fe-core-collapse supernova progenitors and remnant neutron star mass distribution  

Science Journals Connector (OSTI)

......low-mass core-collapse SNe with updated input physics are interesting and important...code [23]. In the UN code, the input physics such as the equation of state...known that, inside these massive stars, nuclear fusion takes place up to Fe synthesis. Before......

Hideyuki Umeda; Takashi Yoshida; Koh Takahashi

2012-01-01T23:59:59.000Z

292

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

E-Print Network (OSTI)

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.

Alex Kaivarainen

2006-07-14T23:59:59.000Z

293

Neutron-capture elements in the s- and r-process-rich stars: Constraints on neutron-capture nucleosynthesis processes  

E-Print Network (OSTI)

The chemical abundances of the very metal-poor double-enhanced stars are excellent information for setting new constraints on models of neutron-capture processes at low metallicity. These stars are known as s+r stars, since they show enhancements of both s-process and r-process elements. The observed abundance ratios for the double-enhanced stars can be explained by those of stars that were polluted by an AGB star and subsequently accreted very significant amounts of r-process material out of an AIC (accretion-induced collapse) or Type 1.5 supernova. In this paper we present for the first time an attempt to fit the elemental abundances observed in the s- and r-rich, very metal-poor stars using a parametric model and suggest a new concept of component coefficients to describe the contributions of the individual neutron-capture processes to double-enhanced stars. We find that the abundance ratios of these stars are best fitted by enrichments of s- and r-process material. The overlap factor in the AGB stars where the observed s-process elements were produced lies between 0.1 and 0.81. Taking into account the dependence of the initial-final mass relations on metallicity, this wide range of values could possibly be explained by a wide range of core-mass values of AGB stars at low metallicity. The component coefficient of the r-process is strongly correlated with the component coefficient of the s-process for the double-enhanced stars. This is significant evidence that the r-process material in double-enhanced stars comes from an AIC or Type 1.5 supernova.

Bo Zhang; Kun Ma; Guide Zhou

2006-05-14T23:59:59.000Z

294

Complete calculation of evaluated Maxwellian-averaged cross sections and their uncertainties for s-process nucleosynthesis  

SciTech Connect

Present contribution represents a significant improvement of our previous calculation of Maxwellian-averaged cross sections and astrophysical reaction rates. Addition of newly-evaluated neutron reaction libraries, such as ROSFOND and Low-Fidelity Covariance Project, and improvements in data processing techniques allowed us to extend it for entire range of sprocess nuclei, calculate Maxwellian-averaged cross section uncertainties for the first time, and provide additional insights on all currently available neutron-induced reaction data. Nuclear reaction calculations using ENDF libraries and current Java technologies will be discussed and new results will be presented.

Pritychenko, B.

2010-07-19T23:59:59.000Z

295

Cosmology at the millennium  

Science Journals Connector (OSTI)

One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding universe comprising billions of galaxies, all held together by dark matter. With the hot big-bang model we can trace the evolution of the Universe from the hot soup of quarks and leptons that existed a fraction of a second after the beginning, to the formation of galaxies a few billion years later, and finally to the Universe we see today 13 billion years after the big bang, with its clusters of galaxies, superclusters, voids, and great walls. The attractive force of gravity acting on tiny primeval inhomogeneities in the distribution of matter gave rise to all the structure seen today. A paradigm based upon deep connections between cosmology and elementary particle physics—inflation+cold dark matter—holds the promise of extending our understanding to an even more fundamental level and much earlier times, as well as shedding light on the unification of the forces and particles of Nature. As we enter the 21st century, a flood of observations is testing this paradigm.

Michael S. Turner and J. Anthony Tyson

1999-03-01T23:59:59.000Z

296

Cosmology at the millennium  

SciTech Connect

One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding universe comprising billions of galaxies, all held together by dark matter. With the hot big-bang model we can trace the evolution of the Universe from the hot soup of quarks and leptons that existed a fraction of a second after the beginning, to the formation of galaxies a few billion years later, and finally to the Universe we see today 13 billion years after the big bang, with its clusters of galaxies, superclusters, voids, and great walls. The attractive force of gravity acting on tiny primeval inhomogeneities in the distribution of matter gave rise to all the structure seen today. A paradigm based upon deep connections between cosmology and elementary particle physics{emdash}inflation+cold dark matter{emdash}holds the promise of extending our understanding to an even more fundamental level and much earlier times, as well as shedding light on the unification of the forces and particles of Nature. As we enter the 21st century, a flood of observations is testing this paradigm. {copyright} {ital 1999} {ital The American Physical Society}

Turner, M.S. [Department of Astronomy Astrophysics and Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637-1433 (United States)] [Department of Astronomy Astrophysics and Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637-1433 (United States); [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States); Tyson, J.A. [Bell Labs, Lucent Technologies, Murray Hill, New Jersey 07974 (United States)] [Bell Labs, Lucent Technologies, Murray Hill, New Jersey 07974 (United States)

1999-03-01T23:59:59.000Z

297

Cosmology at the Millennium  

E-Print Network (OSTI)

One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding Universe comprising billions of galaxies, all held together by dark matter. With the hot big-bang model, we can trace the evolution of the Universe from the hot soup of quarks and leptons that existed a fraction of a second after the beginning to the formation of galaxies a few billion years later, and finally to the Universe we see today 13 billion years after the big bang, with its clusters of galaxies, superclusters, voids, and great walls. The attractive force of gravity acting on tiny primeval inhomogeneities in the distribution of matter gave rise to all the structure seen today. A paradigm based upon deep connections between cosmology and elementary particle physics -- inflation + cold dark matter -- holds the promise of extending our understanding to an even more fu...

Turner, M S; Turner, Michael S.

1999-01-01T23:59:59.000Z

298

Cosmology at the Millennium  

E-Print Network (OSTI)

One hundred years ago we did not know how stars generate energy, the age of the Universe was thought to be only millions of years, and our Milky Way galaxy was the only galaxy known. Today, we know that we live in an evolving and expanding Universe comprising billions of galaxies, all held together by dark matter. With the hot big-bang model, we can trace the evolution of the Universe from the hot soup of quarks and leptons that existed a fraction of a second after the beginning to the formation of galaxies a few billion years later, and finally to the Universe we see today 13 billion years after the big bang, with its clusters of galaxies, superclusters, voids, and great walls. The attractive force of gravity acting on tiny primeval inhomogeneities in the distribution of matter gave rise to all the structure seen today. A paradigm based upon deep connections between cosmology and elementary particle physics -- inflation + cold dark matter -- holds the promise of extending our understanding to an even more fundamental level and much earlier times, as well as shedding light on the unification of the forces and particles of nature. As we enter the 21st century, a flood of observations is testing this paradigm.

Michael S. Turner; J. Anthony Tyson

1999-01-11T23:59:59.000Z

299

Subtraction-noise projection in gravitational-wave detector networks  

SciTech Connect

In this paper, we present a successful implementation of a subtraction-noise projection method into a simple, simulated data analysis pipeline of a gravitational-wave search. We investigate the problem to reveal a weak stochastic background signal which is covered by a strong foreground of compact-binary coalescences. The foreground, which is estimated by matched filters, has to be subtracted from the data. Even an optimal analysis of foreground signals will leave subtraction noise due to estimation errors of template parameters which may corrupt the measurement of the background signal. The subtraction noise can be removed by a noise projection. We apply our analysis pipeline to the proposed future-generation space-borne Big Bang Observer mission which seeks for a stochastic background of primordial gravitational waves in the frequency range {approx}0.1 Hz--1 Hz covered by a foreground of black-hole and neutron-star binaries. Our analysis is based on a simulation code which provides a dynamical model of a time-delay interferometer network. It generates the data as time series and incorporates the analysis pipeline together with the noise projection. Our results confirm previous ad hoc predictions which say that the Big Bang Observer will be sensitive to backgrounds with fractional energy densities below {omega}=10{sup -16}.

Harms, Jan; Mahrdt, Christoph; Otto, Markus; Priess, Malte [Institut fuer Gravitationsphysik, Universitaet Hannover and Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Callinstrasse 38, 30167 Hannover (Germany)

2008-06-15T23:59:59.000Z

300

Bouncing Loop Quantum Cosmology from $F(T)$ gravity  

E-Print Network (OSTI)

The big bang singularity could be understood as a breakdown of Einstein's General Relativity at very high energies. Adopting this viewpoint, other theories, that implement Einstein Cosmology at high energies, might solve the problem of the primeval singularity. One of them is Loop Quantum Cosmology (LQC) with a small cosmological constant that models a universe moving along an ellipse, which prevents singularities like the big bang or the big rip, in the phase space $(H,\\rho)$, where $H$ is the Hubble parameter and $\\rho$ the energy density of the universe. Using LQC when one considers a model of universe filled by radiation and matter where, due to the cosmological constant, there are a de Sitter and an anti de Sitter solution. This means that one obtains a bouncing non-singular universe which is in the contracting phase at early times. After leaving this phase, i.e., after bouncing, it passes trough a radiation and matter dominated phase and finally at late times it expands in an accelerated way (current co...

Amorós, Jaume; Odintsov, Sergei D

2013-01-01T23:59:59.000Z

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While these samples are representative of the content of NLEBeta,
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301

Ramon Eritja Nucleic Acid Chemistry Group  

E-Print Network (OSTI)

, IQAC-CSIC, CIBER-BBN DNA and RNA in Biophysics #12;DNA and RNA Synthesis tetrazol + (CH2)2(CH2)2 R R R

Ritort, Felix

302

PREPRINT An Efficient Algorithm for Geocentric to Geodetic Coordinate...  

Office of Scientific and Technical Information (OSTI)

Conference, pp. 610-615, (1976). 29. Wise, B., Geocentric to Geodetic Coordinate Conversions, BBN Report NO. 7756, May 1992. 19. Military Standard (Final Draft) Protocol...

303

The Secretary of Energy Advisory Board (SEAB) Task Force on Next...  

Energy Savers (EERE)

Raytheon BBN Technologies Dan Reed, University of Iowa Ram Shenoy, ConocoPhillips* Kord Smith, Massachusetts Institute of Technology John Tracy, Boeing *SEAB Member Designated...

304

64Cu-1,4,7-Triazacyclononane-1,4-diacetic acid-para-aminobenzoic acid-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2  

E-Print Network (OSTI)

, 14). Prasanphanich et al. recently reported that the NOTA-based 64Cu-NOTA-8-Aoc-BBN(7­14) NH2 conjugate (where 8-Aoc = 8-aminooctanoic acid) exhibited decreased accumulation in hepatic tissue and maintain the good pharmacokinetic properties of the 64Cu-NOTA-8-Aoc-BBN(7­14)NH2 conjugate, Lane et al

Levin, Judith G.

305

Making the World (of Communications) a Different Place David D. Clark, Craig Partridge, Robert T. Braden, Bruce Davie, Sally Floyd,  

E-Print Network (OSTI)

. Braden, Bruce Davie, Sally Floyd, Van Jacobson, Dina Katabi, Greg Minshall, K.K. Ramakrishnan, Timothy' Affilations: David D. Clark (MIT CSAIL), Craig Partridge (BBN Technologies), Robert T. Braden (USC ISI), Bruce@bbn.com This report is the product of a discussion held at the January 2005 meeting of the End-to-End Research Group

Chen, Yuanzhu Peter

306

Fermilab Cultural Events in Chicago's Far West Side  

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Art Gallery Header Public Access current show schedule contact us cultural events archive General Information Art Gallery Header Public Access current show schedule contact us cultural events archive General Information "I have always felt that science, technology, and art are importantly connected, indeed science and technology seem to many scholars to have grown out of art." -Robert Rathbun Wilson This convergence of art and science occurs daily in the Fermilab Art Gallery. It is a space for art exhibitions, chamber music concerts and where the top quark and big bang are debated over coffee. It is also a quiet space for contemplation and beauty. Current Status of Access to Fermilab Fermilab Examined – a Juried Exhibition by members of the Fermilab Photography Club 11/18/13-1/26/14 Artist Reception 11/20/13 Current Exhibition Upcoming Exhibition

307

NEWTON, Ask a Scientist at Argonne National Labs  

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Number of Galaxies and Expansion Number of Galaxies and Expansion Name: Kurt Status: other Grade: other Location: CA Country: Austria Date: Fall 2011 Question: Our telescopes show us that in the far reaches of space seem to be more galaxies and they are moving away from each other with ever increasing speed. scientists say that the moving away from each other is actually "stretching of space," should we not see fewer galaxies for that reason? Replies: Dear Kurt, I think that Hubble's idea of the expanding Universe means that the superclusters of galaxies -- not the galaxies or clusters,. but the clusters of clusters, are actually moving apart from each other. They have been doing this since the Big Bang. We do not see the farthest galaxies because their light has not reached us yet,

308

Research Highlights | ORNL Neutron Sciences  

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Neutron/Proton Capture Neutron/Proton Capture Beam Line 13 Fuels Discovery Fever for Fundamental Physicists Research Contact: Geoff Greene June 2011, Written by Agatha Bardoel Serpil Kucuker Dogan (left) and Matthew Musgrave prepare a helium-3 cooling cell that is used to measure the angle at which the neutron beam strikes the liquid hydrogen sample. The simplest, most sensible " Big Bang" universe, theoretical physicists believe, would be one in which equal numbers of particles and antiparticles are formed in pairs. As the universe cools, most of these particles would encounter their antiparticles, and they would annihilate. "In many ways, the most reasonable universe would be one in which there is no matter," says the University of Tennessee's Dr. Geoff Greene.

309

The supernova that destroyed a galaxy  

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The supernova that destroyed a galaxy The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the centers of some galaxies less then a billion years after the Big Bang. August 5, 2013 Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) The Los Alamos simulation is the most realistic cosmological supernova simulation ever performed of this process. New supercomputer simulations by Los Alamos scientists and collaborators capture in unprecedented detail extremely powerful supernovae explosions in the early universe and their effect on the nascent galaxies that gave birth

310

U.S. CMS - 2009 News Archive  

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9 News Archive 9 News Archive In This Section: CMS in the News Press Releases Press Kit CMS Result of the Month Other News Sources: US LHC Interactions.org U.S. CMS Past News Archives: 2012 News Archive 2011 News Archive 2010 News Archive 2009 News Archive 2008 News Archive 2007 News Archive Current news archive December 18, 2009 Interactions News Wire LHC ends 2009 run on a high note December 18, 2009 ABC News Big Bang Collider sets new record December 16, 2009 symmetry breaking Burst of LHC collision data a welcome birthday gift December 11, 2009 Fermilab Today CMS Result of the Month: Simply smashing December 9, 2009 New York Times Collider sets record, and Europe takes U.S.'s lead December 9, 2009 Fermilab Today CMS says hello to the π0 January 2010 Vanity Fair The Genesis 2.0 Project December 7, 2009

311

Page not found | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

11 - 11020 of 31,917 results. 11 - 11020 of 31,917 results. Article A Cure for the Valentine's Blues? Livermore Supercomputer Seeks to Mend Broken Hearts Cupid's arrows may help you find love, but an Energy Department supercomputer is working to help cure broken hearts. http://energy.gov/articles/cure-valentines-blues-livermore-supercomputer-seeks-mend-broken-hearts Article Sweet Sunbeams and Creative Catalysts Opening a new window on the way plants generate the oxygen we breathe, SLAC simultaneously looks at the structure and chemical behavior of photosynthesis. http://energy.gov/articles/sweet-sunbeams-and-creative-catalysts Article Supercomputing: A Toolbox to Simulate the Big Bang and Beyond Learn how three Energy Department National Labs are collaborating to peer deeper into the origins of our universe than ever before.

312

H O  

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O O I - * , TWl rrporl «lf pnpmd u u iccouni of work fponiortd by fbc Unfad Suirs Gomuncnl. KtHka U» Unllii s u m nor Ih. Vaiui SHIM Atomic EnotT Comminjon, oar cur or tncir cnptoynf. nor Mr of ihtk caatrutott, ubcoRtmuirB, or tlwk cmptorra. milMsuir w n a f r . «prM§orimp&cd.of iMnmauy _ { l i . UBl Ibbililr or raponiiMlitr ror Ui. n e o n , , cum- *** pUUuu or tmfol«B or W larornutloa. ippiniia. proaoct or procac rfiKlowd. or rtprucnu Out iu use would not fafrinf* pririirly owned rifntr. FAR INFRARED SPECTROMETRY OF THE COSMIC BACKGROUND RADIATION Contents Abstract iii I. Introduction 1 A. Theory of the Background Radiation 2 1. Big Bang Theory 2 2. Primeval Perturbations 3 3. Later Perturbations 5 4. Recent Perturbations 5 B. Observations 6 1. Long Wavelength Direct Observations 7

313

Argonne CNM: 2012 Colloquium Series  

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2 Colloquium Series 2 Colloquium Series 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | Date Title Special Colloquium December 13, 2012 "Pathways to Complex Matter Far-Away-From Equilibrium: Developing Spatiotemporal Tools," by Gopal Shenoy, Argonne National Laboratory, hostged by Daniel Lopez Abstract: From the Big Bang to the coming of humankind, every manifestation of nature has exhibited processes far-away-from equilibrium leading to increasingly complex structural orders from geological to atomic length and time scales. Examples include the evolution of galaxies, hurricanes, stars, and planets; prebiotic reactions; cyclical reactions; photosynthesis; and life itself. The organizational spatiotemporal evolution in soft, hard, and biological matter also follows the same path. It begins from a far-from-equilibrium state and develops over time into organizations with length scales between atoms and small molecules on the one hand and mesoscopic matter on the other.

314

Fermilab Today | Experiment Profiles Archive | DAMIC  

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DAMIC DAMIC photo FACT SHEET: Click here to download PDF. NAME: Dark Matter In CCDs, or DAMIC The ORIGIN OF THE NAME: DAMIC searches for dark matter using Charge Coupled Devices. These digital chips register light that gets converted into a digital value a computer can store. WHAT WILL THIS TELL? Everything you see, visible matter, makes up 4 percent of the universe. Dark matter and dark energy make up the rest of the universe. Physicists understand that dark matter acts as an invisible source of gravity, but little more. DAMIC seeks to pinpoint what particles make up dark matter, which will help explain how the universe came to exist. Without the added gravitational attraction of dark matter, stars and galaxies would have never formed. The expansion of the universe after the Big Bang would have dispersed visible

315

RHIC | Relativistic Heavy Ion Collider  

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Relativistic Heavy Ion Collider Relativistic Heavy Ion Collider Photo of LINAC The Relativistic Heavy Ion Collider (RHIC) is a world-class particle accelerator at Brookhaven National Laboratory where physicists are exploring the most fundamental forces and properties of matter and the early universe. RHIC accelerates beams of particles (e.g., the nuclei of heavy atoms such as gold) to nearly the speed of light, and smashes them together to recreate a state of matter thought to have existed immediately after the Big Bang some 13.8 billion years ago. STAR and PHENIX, two large detectors located around the 2.4-mile-circumference accelerator, take "snapshots" of these collisions to reveal a glimpse of the basic constituents of visible matter, quarks and gluons. Understanding matter at

316

Files for the 2012 booklet production  

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Files for the 2012 booklet production Files for the 2012 booklet production Name pages tar file PDF Comments Accelerator Physics of Colliders 1 accel.tar accel-db.pdf July 31, 2012 Big-Bang Cosmology 6 bigbang.tar bigbang-db.pdf July 31, 2012 CKM quark-mixing matrix 7 kmmix.tar kmmix-db.pdf July 31, 2012 Cosmic Microwave Background 3 microwave.tar microwave-db.pdf July 31, 2012 Cosmic Rays 1 cosmicray.tar cosmicray-db.pdf July 31, 2012 Cosmological Parameters, The 4 hubble.tar hubble-db.pdf July 31, 2012 CP violation 5 cpviol.tar cpviol-db.pdf July 31, 2012 Dark matter 3 darkmat.tar darkmat-db.pdf July 31, 2012 Electroweak model ... 9 stanmodel.tar stanmodel-db.pdf July 31, 2012 Grand Unified Theories 6 guts.tar guts-db.pdf August 14, 2012

317

Planetary formation theory developed, tested: predicts timeline for life  

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Planetary formation theory developed, tested: predicts timeline for Planetary formation theory developed, tested: predicts timeline for life After the Big Bang: Theory suggests first planets formed after first generations of stars The researchers' calculations predict properties of first planet and timeline for life. May 3, 2012 image description The researchers state that the formation of Earth-like planets is not itself a sufficient prerequisite for life. Early galaxies contained strong sources of life-threatening radiation, such as supernovae and black holes. Therefore, they conclude that the conditions for life emerged only after the earliest epoch of galaxy formation. Get Expertise Jarrett Johnson Nuclear and Particle Physics, Astrophysics and Cosmology Email Hui Li Nuclear and Particle Physics, Astrophysics and Cosmology

318

The supernova that destroyed a galaxy  

NLE Websites -- All DOE Office Websites (Extended Search)

August » August » The supernova that destroyed a galaxy The supernova that destroyed a galaxy The research may solve the long-standing puzzle of how supermassive black holes were formed in the centers of some galaxies less then a billion years after the Big Bang. August 5, 2013 Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) Supernova of a 55,000 solar-mass star in a primitive galaxy (explosion in a low-density region) The Los Alamos simulation is the most realistic cosmological supernova simulation ever performed of this process. New supercomputer simulations by Los Alamos scientists and collaborators capture in unprecedented detail extremely powerful supernovae explosions in the early universe and their effect on the nascent galaxies that gave birth

319

Particle Physics Education Sites  

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쭺-¶ 쭺-¶ Particle Physics Education Sites ¡]¥H¤U¬°¥~¤åºô¯¸¡^ quick reference Education and Information - National Laboratory Education Programs - Women and Minorities in Physics - Other Physics Sites - Physics Alliance - Accelerators at National Laboratories icon Particle Physics Education and Information sites: top Introduction: The Particle Adventure - an interactive tour of particle physics for everyone: the basics of theory and experiment. Virtual Visitor Center of the Stanford Linear Accelerator Center. Guided Tour of Fermilab, - overviews of several aspects of Particle Physics. Also check out Particle Physics concepts. Probing Particles - a comprehensive and straight-forward introduction to particle physics. Big Bang Science - approaches particle physics starting from the theoretical origin of the universe.

320

BNL | Neutrino Research History  

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Brookhaven Neutrino Research Brookhaven Neutrino Research image of neutrinos Tens of billions of neutrinos are passing through every square centimeter of the Earth's surface right now. A Ghost-Particle Retrospective Neutrinos, ghostlike particles that flooded the universe just moments after the Big Bang, are born in the hearts of stars and other nuclear reactions. Untouched by electromagnetism and nearly as fast as light, neutrinos pass practically unhindered through everything from planets to people, only rarely responding to the weak nuclear force and the even weaker gravity. In fact, at any given moment, tens of billions of neutrinos are passing through every square centimeter of the Earth's surface. Neutrino Research News photomultiplier tubes New Results from Daya Bay: Tracking the Disappearance of Ghostlike

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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321

The Universe Adventure - Feedback  

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Contact Us Contact Us First Name (optional): Simpson Last Name (optional): Homer E-Mail Address (if you would like to hear back from us): How can we contact you? Occupation (high school student, physics teacher, cosmologist, et cetera): What is your occupation? Type: Type of Feedback Organization/Format Content Fundamentals of Cosmology Evidence for the Big Bang Eras of the Cosmos The Final Frontier Glossary Other Comments and Feedback: We appreciate your comments! - The Universe Adventure Team submit reset [ top ] Site Content National Science Foundation Department of Energy S.D. Bechtel, Jr. Foundation [ Site Map ] optimized for Firefox [ UC Berkeley ] [ UC Berkeley Physics ] [ Particle Adventure! ] [ Contact Us ] Copyright © 2005 Lawrence Berkeley National Laboratory Physics Division |

322

Top Science of 2013  

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RAPTOR telescope witnesses black hole birth RAPTOR telescope witnesses black hole birth /science-innovation/_assets/images/icon-science.jpg Top Science of 2013 Our strong interdisciplinary teaming and unique research facilities allow us to develop solutions to complex problems, and to support partners and collaborators, all with the goal of strengthening national security and making a safer world. RAPTOR telescope witnesses black hole birth placeholder The first "thinking telescope" RAPTOR found the 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 us when there's a discovery or a threat. In 2006, RAPTOR was the first of its kind to make a discovery: the birth of

323

LHC Workshop 2011  

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Matter / Antimatter Asymmetry Matter / Antimatter Asymmetry The big bang should have created equal amounts of matter and antimatter in the early universe. But today, everything we see from the smallest life forms on Earth to the largest stellar objects is made almost entirely of matter. Comparatively, there is not much antimatter to be found. Something must have happened to tip the balance. One of the greatest challenges in physics is to figure out what happened to the antimatter, or why we see matter/antimatter asymmetry. Read More Antimatter particles share the same mass as their matter counterparts, but they carry an opposite electric charge. The positively charged positron, for example, is the anti-particle to the negatively charged electron. Matter and antimatter particles are always produced as a pair and, if they

324

Fermilab | Science at Fermilab | Questions for the Universe | The Birth of  

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Tevatron, Fermilab, Batavia, IL Tevatron, Fermilab, Batavia, IL Large Hadron Collider, CERN, Geneva, Switzerland BaBar, SLAC, Menlo Park, CA Further reading courtesy of Symmetry magazine Explain it in 60 Seconds: Antimatter Explain it in 60 Seconds: CP violation BaBar's Window on the Weak Force Persis Drell Where has all the antimatter gone? Persis Drell, director of SLAC National Accelerator Laboratory, explains how answering questions about antimatter may shed light on what happened in the early universe. View the Video What happened to the antimatter? Experiments teach us that for every fundamental particle there exists an antiparticle. The big bang and its aftermath almost certainly produced particles and antiparticles in equal numbers. However, for as far out in the universe as we can probe, our observations indicate that we live in a

325

The Universe Adventure - The Modern Universe  

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Modern Universe Modern Universe Like astronomers throughout history, modern cosmologists are interested in making an accurate model of the Universe. Starting with the laws of physics which explain how fundamental particles and forces interact, physicists derive general equations describing the evolution of the Universe's structure. Cosmologists use experimental evidence to select a set of initial conditions enabling them to solve the general equations, and calculate the state of the Universe at times in the past, present, or future. This generates a possible model, which can be tested by comparing the phenomena it predicts with observational data. In this manner, following the rigorous scientific method, cosmologists work to build a successful Universal model. In the next section we will examine evidence for the current Big Bang

326

Sandia National Laboratories: News: Publications: Lab News  

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Sept. 21, 2012 Sept. 21, 2012 Sandia's Explosives Technology Group discovers key detonation behavior in common explosive NOT SO BIG BANG - Alex Tappan (left) and Rob Knepper (both 2554) watch the detonation of a Sandia critical thickness experiment. The experiment typically uses less explosive material than the size of one-tenth of an aspirin tablet to determine small-scale detonation properties. The bench-top experiment is so small, researchers can stand next to the firing chamber with eye and ear protection. (Photo by Randy Montoya) by Sue Major Holmes The explosive PETN (pentaerythritol tetranitrate) has been around for a century and is used by everyone from miners to the military, but it took new research by Sandia to begin to discover key mechanisms behind what causes it to fail at very small scales.

327

 

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Stellar Fusion Cross Sections Underground Stellar Fusion Cross Sections Underground Daniel Bemmerer Forschungszentrum Dresden-Rossendorf (FZD) Abstract: Due to the suppression by the Coulomb barrier, the cross sections of astrophysically relevant nuclear reactions are very low at the stellar energy. Therefore they can only be directly measured in a low-background environment. For more than a decade now, the LUNA collaboration has pursued this approach with a 0.4 MV accelerator in the Gran Sasso underground laboratory in Italy. It was highly successful in studying the nuclear physics of the Sun and of the Big Bang. However, the energy range of LUNA is not sufficient to address the nuclear reactions of stellar helium and carbon burning and the neutron source reactions for the astrophysical s-process. Therefore, in the 2010 NuPECC

328

DOE Research and Development Accomplishments RSS Archive 2005-2006  

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5-2006 5-2006 2007 · 2008 · 2009 George Smoot Courtesy of Lawrence Berkeley National Laboratory "Blackbody Form" Research Yields 2006 Nobel Prize George Smoot made an announcement in 1992 that "essentially silenced all the scientific critics of the Big Bang theory." (See the October 3, 2006 edition of Today at Berkeley Lab.) For research leading up to that announcement, Smoot was awarded the Nobel Prize in Physics 2006. Smoot, an astrophysicist at Berkeley Lab since 1974 and a UC Berkeley physics professor since 1994, shared the award with John C. Mather of NASA Goddard Space Flight Center. Together they discovered the blackbody form and anisotropy of the cosmic microwave background radiation. Read more on this discovery at the DOE R&D Accomplishments Featured Scientists page.

329

Experiment Profile: COUPP NAME: Chicagoland Observatory for Underground Particle  

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COUPP COUPP NAME: Chicagoland Observatory for Underground Particle Physics, or COUPP WHAT WILL THIS TELL US ABOUT THE WORLD? Everything you see, visible matter, makes up 4 percent of the universe. Dark matter and dark energy makes up the rest of the universe. Physicists understand that dark matter acts as an invisible source of gravity, but little more. COUPP seeks to pinpoint what particles make up dark matter, which will help explain how the universe came to exist. Without the added gravitational attraction of dark matter, stars and galaxies would never have formed. The expansion of the universe after the Big Bang would have dispersed visible matter too quickly. WHY IS THIS EXPERIMENT NEEDED NOW? Physicists have narrowed the hunt for what particles constitute dark

330

COBE Sky Map  

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COBE sky map COBE sky map This map of the ancient sky shows the minute variations in the microwave background discovered by the team led by Lawrence Berkeley Laboratory astrophysicist George Smoot. As seen in the map, vast regions of space have minute variations in temperature. Over billions of years, gravity magnified these small differences into the clusters of galaxies we observe today. Displayed horizontally across the middle of the map is the Milky Way galaxy. The image, a 360-degree map of the whole sky, shows the relic radiation from the Big Bang. The map was derived from one year of data taken by the Differential Microwave Radiometers onboard NASA's Cosmic Background Explorer satellite. Using Galactic coordinates, the map shows the plane of the Milky Way galaxy horizontally and the center of our galaxy at its

331

Brookhaven National Laboratory The Relativistic Heavy Ion Collider (RHIC)  

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Relativistic Heavy Ion Collider (RHIC) Relativistic Heavy Ion Collider (RHIC) An Exciting Beginning and a Compelling Future At the Relativistic Heavy Ion Collider (RHIC), a world-class particle accelerator at Brookhaven National Laboratory, physicists are exploring the most fundamental forces and properties of matter and the early universe, with important implications for our understanding of the world around us. Operated with funding from the U.S. Department of Energy's Office of Science, the Relativistic Heavy Ion Collider (RHIC), was designed to recreate a state of matter thought to have existed immediately after the Big Bang some 13 billion years ago, and to investigate how the proton gets its spin and intrinsic magnetism from its quark and gluon constituents. Large detectors located

332

The Universe Adventure - Current Research  

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Current Research Current Research When launched, the Supernova Acceleration Probe (SNAP) will study the effects of dark energy by surveying distant type Ia supernovae and making detailed measurements of weak gravitational lensing. With the new Large Hadron Collider (LHC) at CERN nearing full completion, experimentalists will soon be able to test certain elements of String Theory. While not definitive, these tests will cast some light upon the theory's parameters and may even provide clues into the identity of dark matter. Meanwhile, theorists continue to investigate the implications of String Theory for Big Bang cosmology, particularly the effects of strings on cosmic inflation. As particle physicists eagerly await the results from the new LHC, observational cosmologists are busy developing astronomical experiments,

333

SciDAC Visualization and Analytics Center for EnablingTechnologies  

SciTech Connect

The Visualization and Analytics Center for EnablingTechnologies (VACET) focuses on leveraging scientific visualization andanalytics software technology as an enabling technology for increasingscientific productivity and insight. Advances in computational technologyhave resulted in an 'information big bang,' which in turn has created asignificant data understanding challenge. This challenge is widelyacknowledged to be one of the primary bottlenecks in contemporaryscience. The vision of VACET is to adapt, extend, create when necessary,and deploy visual data analysis solutions that are responsive to theneeds of DOE'scomputational and experimental scientists. Our center isengineered to be directly responsive to those needs and to deliversolutions for use in DOE's large open computing facilities. The researchand development directly target data understanding problems provided byour scientific application stakeholders. VACET draws from a diverse setof visualization technology ranging from production quality applicationsand application frameworks to state-of-the-art algorithms forvisualization, analysis, analytics, data manipulation, and datamanagement.

Bethel, E. Wes; Johnson, Chris; Joy, Ken; Ahern, Sean; Pascucci,Valerio; Childs, Hank; Cohen, Jonathan; Duchaineau, Mark; Hamann, Bernd; Hansen, Charles; Laney, Dan; Lindstrom, Peter; Meredith, Jermey; Ostrouchov, George; Parker, Steven; Silva, Claudio; Sanderson, Allen; Tricoche, Xavier.

2007-06-30T23:59:59.000Z

334

Reconstruction of a nonminimal coupling theory with scale-invariant power spectrum  

SciTech Connect

A nonminimal coupling single scalar field theory, when transformed from Jordan frame to Einstein frame, can act like a minimal coupling one. Making use of this property, we investigate how a nonminimal coupling theory with scale-invariant power spectrum could be reconstructed from its minimal coupling counterpart, which can be applied in the early universe. Thanks to the coupling to gravity, the equation of state of our universe for a scale-invariant power spectrum can be relaxed, and the relation between the parameters in the action can be obtained. This approach also provides a means to address the Big-Bang puzzles and anisotropy problem in the nonminimal coupling model within Jordan frame. Due to the equivalence between the two frames, one may be able to find models that are free of the horizon, flatness, singularity as well as anisotropy problems.

Qiu, Taotao, E-mail: qiutt@ntu.edu.tw [Leung Center for Cosmology and Particle Astrophysics National Taiwan University, Taipei 106, Taiwan (China)

2012-06-01T23:59:59.000Z

335

The string wave function across a Kasner singularity  

E-Print Network (OSTI)

A collision of orbifold planes in eleven dimensions has been proposed as an explanation of the hot big bang. When the two planes are close to each other, the winding membranes become the lightest modes of the theory, and can be effectively described in terms of fundamental strings in a ten dimensional background. Near the brane collision, the eleven-dimensional metric is an Euclidean space times a 1+1-dimensional Milne universe. However, one may expect small perturbations to lead into a more general Kasner background. In this paper we extend the previous classical analysis of winding membranes to Kasner backgrounds, and using the Hamiltonian equations, solve for the wave function of loops with circular symmetry. The evolution across the singularity is regular, and explained in terms of the excitement of higher oscillation modes. We also show there is finite particle production and unitarity is preserved.

Edmund J. Copeland; Gustavo Niz; Neil Turok

2010-01-28T23:59:59.000Z

336

Local Conformal Symmetry in Physics and Cosmology  

E-Print Network (OSTI)

We show how to lift a generic non-scale invariant action in Einstein frame into a locally conformally-invariant (or Weyl-invariant) theory and present a new general form for Lagrangians consistent with Weyl symmetry. Advantages of such a conformally invariant formulation of particle physics and gravity include the possibility of constructing geodesically complete cosmologies. We present a conformal-invariant version of the standard model coupled to gravity, and show how Weyl symmetry may be used to obtain unprecedented analytic control over its cosmological solutions. Within this new framework, generic FRW cosmologies are geodesically complete through a series of big crunch - big bang transitions. We discuss a new scenario of cosmic evolution driven by the Higgs field in a \\textquotedblleft minimal\\textquotedblright% \\ conformal standard model, in which there is no new physics beyond the standard model at low energies, and the current Higgs vacuum is metastable as indicated by the latest LHC data.

Itzhak Bars; Paul Steinhardt; Neil Turok

2013-07-07T23:59:59.000Z

337

Energy density fluctuations in early universe  

SciTech Connect

The primordial nucleosinthesys of the element can be influenced by the transitions of phase that take place after the Big Bang, such as the QCD transition. In order to study the effect of this phase transition, in this work we compute the time evolution of thermodynamical quantities of the early universe, focusing on temperature and energy density fluctuations, by solving the relevant equations of motion using as input the lattice QCD equation of state to describe the strongly interacting matter in the early universe plasma. We also study the effect of a primordial strong magnetic field by means of a phenomenological equation of state. Our results show that small inhomogeneities of strongly interacting matter in the early Universe are moderately damped during the crossover.

Guardo, G. L.; Ruggieri, M. [Department of Physics and Astronomy, University of Catania, Catania (Italy); Greco, V. [Department of Physics and Astronomy, University of Catania, Catania, Italy and INFN - Laboratori Nazionali del Sud, Catania (Italy)

2014-05-09T23:59:59.000Z

338

Recombinant Science: The Birth of the Relativistic Heavy Ion Collider (431st Brookhaven Lecture)  

SciTech Connect

As part of the celebration of Brookhaven Lab's 60th anniversary, Robert P. Crease, the Chair of the Philosophy Department at Stony Brook University and BNL's historian, will present the second of two talks on the Lab's history. In "Recombinant Science: The Birth of the Relativistic Heavy Ion Collider," Dr. Crease will focus on the creation of the world's most powerful colliding accelerator for nuclear physics. Known as RHIC, the collider, as Dr. Crease will recount, was formally proposed in 1984, received initial construction funding from the U.S. Department of Energy in 1991, and started operating in 2000. In 2005, the discovery at RHIC of the world's most perfect liquid, a state of matter that last existed just moments after the Big Bang, was announced, and, since then, this perfect liquid of quarks and gluons has been the subject of intense study.

Crease, Robert P. (Ph.D, Department of Philosophy, Stony Brook University) [Ph.D, Department of Philosophy, Stony Brook University

2007-12-12T23:59:59.000Z

339

Review of Particle Physics, 2010-2011  

E-Print Network (OSTI)

This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2158 new measurements from 551 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on neutrino mass, mixing, and oscillations, QCD, top quark, CKM quark-mixing matrix, Vud & Vus, Vcb & Vub, fragmentation functions, particle detectors for accelerator and non-accelerator physics, magnetic monopoles, cosmological parameters, and big bang cosmology.

Nakamura, K; Hikasa, K; Murayama, H; Tanabashi, M; Watari, T; Amsler, C; Antonelli, M; Asner, D M; Baer, H; Band, H R; Barnett, R M; Basaglia, T; Bergren, E; Beringer, J; Bernardi, G; Bertl, W; Bichsel, H; Biebel, O; Blucher, E; Blusk, S; Cahn, R N; Carena, M; Ceccucci, A; Chakraborty, D; Chen, M-C; Chivukula, R S; Cowan, G; Dahl, O; D’Ambrosio, G; Damour, T; de Florian, D; de Gouvêa, A; DeGrand, T; Dissertori, G; Dobrescu, B; Doser, M; Drees, M; Edwards, D A; Eidelman, S; Erler, J; Ezhela, V V; Fetscher, W; Fields, B D; Foster, B; Gaisser, T K; Garren, L; Gerber, H-J; Gerbier, G; Gherghetta, T; Giudice, G F; Golwala, S; Goodman, M; Grab, C; Gritsan, A V; Grivaz, J-F; Groom, D E; Grünewald, M; Gurtu, A; Gutsche, T; Haber, H E; Hagmann, C; Hayes, K G; Heffner, M; Heltsley, B; Hernández-Rey, J J; Höcker, A; Holder, J; Huston, J; Jackson, J D; Johnson, K F; Junk, T; Karle, A; Karlen, D; Kayser, B; Kirkby, D; Klein, S R; Kolda, C; Kowalewski, R V; Krusche, B; Kuyanov, Yu V; Kwon, Y; Lahav, O; Langacker, P; Liddle, A; Ligeti, Z; Lin, C-J; Liss, T M; Littenberg, L; Lugovsky, K S; Lugovsky, S B; Lys, J; Mahlke, H; Mannel, T; Manohar, A V; Marciano, W J; Martin, A D; Masoni, A; Milstead, D; Miquel, R; Mönig, K; Narain, M; Nason, P; Navas, S; Nevski, P; Nir, Y; Olive, K A; Pape, L; Patrignani, C; Peacock, J A; Petcov, S T; Piepke, A; Punzi, G; Quadt, A; Raby, S; Raffelt, G; Ratcliff, B N; Richardson, P; Roesler, S; Rolli, S; Romaniouk, A; Rosenberg, L J; Rosner, J L; Sachrajda, C T; Sakai, Y; Salam, G P; Sarkar, S; Sauli, F; Schneider, O; Scholberg, K; Scott, D; Seligman, W G; Shaevitz, M H; Silari, M; Sjöstrand, T; Smith, J G; Smoot, G F; Spanier, S; Spieler, H; Stahl, A; Stanev, T; Stone, S L; Sumiyoshi, T; Syphers, M J; Terning, J; Titov, M; Tkachenko, N P; Törnqvist, N A; Tovey, D; Trippe, T G; Valencia, G; van Bibber, K; Venanzoni, G; Vincter, M G; Vogel, P; Vogt, A; Walkowiak, W; Walter, C W; Ward, D R; Webber, B R; Weiglein, G; Weinberg, E J; Wells, J D; Wheeler, A; Wiencke, L R; Wohl, C G; Wolfenstein, L; Womersley, J; Woody, C L; Workman, R L; Yamamoto, A; Yao, W-M; Zenin, O V; Zhang, J; Zhu, R-Y; Zyla, P A; Harper, G; Lugovsky, V S; Schaffner, P

2010-01-01T23:59:59.000Z

340

Big Questions: Missing Antimatter  

SciTech Connect

Einstein's equation E = mc2 is often said to mean that energy can be converted into matter. More accurately, energy can be converted to matter and antimatter. During the first moments of the Big Bang, the universe was smaller, hotter and energy was everywhere. As the universe expanded and cooled, the energy converted into matter and antimatter. According to our best understanding, these two substances should have been created in equal quantities. However when we look out into the cosmos we see only matter and no antimatter. The absence of antimatter is one of the Big Mysteries of modern physics. In this video, Fermilab's Dr. Don Lincoln explains the problem, although doesn't answer it. The answer, as in all Big Mysteries, is still unknown and one of the leading research topics of contemporary science.

Lincoln, Don

2013-08-27T23:59:59.000Z

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341

Observation of an Antimatter Hypernucleus  

SciTech Connect

Nuclear collisions recreate conditions in the universe microseconds after the Big Bang. Only a very small fraction of the emitted fragments are light nuclei, but these states are of fundamental interest. We report the observation of antihypertritons - composed of an antiproton, antineutron, and antilambda hyperon - produced by colliding gold nuclei at high energy. Our analysis yields 70 {+-} 17 antihypertritons ({sub {bar {Lambda}}}{sup 3}{bar H}) and 157 {+-} 30 hypertritons ({sub {Lambda}}{sup 3}H). The measured yields of {sub {Lambda}}{sup 3}H ({sub {bar {Lambda}}}{sup 3}{bar H}) and {sup 3}He ({sup 3}{ovr He}) are similar, suggesting an equilibrium in coordinate and momentum space populations of up, down, and strange quarks and antiquarks, unlike the pattern observed at lower collision energies. The production and properties of antinuclei, and nuclei containing strange quarks, have implications spanning nuclear/particle physics, astrophysics, and cosmology.

STAR Collaboration; Abelev, Betty

2010-07-05T23:59:59.000Z

342

Analytic solutions to Riemann-squared gravity with background isotropic torsion  

E-Print Network (OSTI)

Motivated by conventional gauge theories, we consider a theory of gravity in which the Einstein-Hilbert action is replaced by a term that is quadratic in the Riemann tensor. We focus on cosmological solutions to the field equations in flat, open and closed universes. The gravitational action is scale invariant, so the only matter source considered is radiation. The theory can also accommodate isotropic torsion and this generically removes singularities from the evolution equations. For general initial conditions the Hubble parameter H(t) is driven in a seemingly chaotic fashion by torsion to produce irregularly occuring inflationary regions. In the absence of torsion, the theory reproduces the standard cosmological solutions of a simple big bang model. A satisfying feature is that a cosmological constant arises naturally as a constant of integration, and does not have to be put into the Lagrangian by hand.

A. N. Lasenby; C. J. L. Doran; R. Heineke

2005-09-02T23:59:59.000Z

343

A Cosmological Model of Thermodynamic Open Universe  

E-Print Network (OSTI)

In this paper we have given a generalisation of the earlier work by Prigogine et al. who have constructed a phenomenological model of entropy production via particle creation in the very early universe generated out of the vacuum rather than from a singularity, by including radiation also as the energy source and tried to develop an alternative cosmological model in which particle creation prevents the big bang. We developed Radiation dominated model of the universe which shows a general tendency that (i) it originates from instability of vacuum rather than from a singularity. (ii) Up to a characteristic time cosmological quantities like density, pressure, Hubble constant and expansion parameter vary rapidly with time. (iii) After the characteristic time these quantities settles down and the models are turned into de-sitter type model with uniform matter, radiation, creation densities and Hubble's constant H. The de-sitter regime survives during a decay time then connects continuously to a usual adiabatic mat...

Goswami, G K

2012-01-01T23:59:59.000Z

344

Supermassive Black Holes  

E-Print Network (OSTI)

Supermassive black holes have generally been recognized as the most destructive force in nature. But in recent years, they have undergone a dramatic shift in paradigm. These objects may have been critical to the formation of structure in the early universe, spawning bursts of star formation and nucleating proto-galactic condensations. Possibly half of all the radiation produced after the Big Bang may be attributed to them, whose number is now known to exceed 300 million. The most accessible among them is situated at the Center of Our Galaxy. In the following pages, we will examine the evidence that has brought us to this point, and we will understand why many expect to actually image the event horizon of the Galaxy's central black hole within this decade.

Fulvio Melia

2007-05-10T23:59:59.000Z

345

A modest proposal to solve the "missing mass" problem and related cosmological paradoxes  

E-Print Network (OSTI)

Properly interpreted data from nearby galaxies $(z\\simeq 0.01)$ lead to $\\Omega \\simeq 0.082$. Data from farther away galaxies $(z\\simeq 1)$ with type Ia supernovae to $\\Omega =0.153$. Data to be expected from very high redshifted galaxies $(z\\simeq 10.1)$ to $\\Omega =0.500$. And actual data from the CBR, emitted at the time at which the universe became transparent $(z\\simeq 1422)$ to $\\Omega \\simeq 0.992$. All these data are simultaneously consistent with the standard big-bang picture (no inflation), in which $ \\Omega $ is time dependent and it is given by $\\Omega (y)=1/\\cosh ^{2}(y)$, being $y\\equiv \\sinh ^{-1}(T_{+}/T)^{1/2}$

J. A. Gonzalo

2000-10-26T23:59:59.000Z

346

Correspondence Between $5D$ Ricci-Flat Cosmological Models and Quintessence Dark Energy Models  

E-Print Network (OSTI)

We study the accelerating expansion and the induced dark energy of the $5D$ Ricci-flat universe which is characterized by having a big bounce as opposed to a big bang. We show that the arbitrary function $\\mu(t)$ contained in the $5D$ solutions can be rewritten in terms of the redshift $z$ as a new arbitrary function $f(z)$, and we find that there is a correspondence between this $f(z)$ and the potential $V(\\phi)$ of the 4D quintessence models. Using this correspondence, the arbitrary function $f(z)$ and the $5D$ solution could be specified for a given form of the potential $V(\\phi)$.

Lixin Xu; Hongya Liu; Baorong Chang

2005-12-26T23:59:59.000Z

347

Protein folding and cosmology  

E-Print Network (OSTI)

Protein denaturing induced by supercooling is interpreted as a process where some or all internal symmetries of the native protein are spontaneously broken. Hence, the free-energy potential corresponding to a folding-funnel landscape becomes temperature-dependent and describes a phase transition. The idea that deformed vortices could be produced in the transition induced by temperature quenching, from native proteins to unfolded conformations is discussed in terms of the Zurek mechanism that implements the analogy between vortices, created in the laboratory at low energy, and the cosmic strings which are thought to have been left after symmetry breaking phase transitions in the early universe. An experiment is proposed to test the above idea which generalizes the cosmological analogy to also encompass biological systems and push a step ahead the view that protein folding is a biological equivalent of the big bang.

González-Diáz, P F

1997-01-01T23:59:59.000Z

348

Optimal allocation of stochastically dependent renewable energy based distributed generators in unbalanced distribution networks  

Science Journals Connector (OSTI)

Abstract This paper proposes an algorithm for modeling stochastically dependent renewable energy based distributed generators for the purpose of proper planning of unbalanced distribution networks. The proposed algorithm integrate the diagonal band Copula and sequential Monte Carlo method in order to accurately consider the multivariate stochastic dependence between wind power, photovoltaic power and the system demand. Secondly, an efficient algorithm based on modification of the traditional Big Bang-Big crunch method is proposed for optimal placement of renewable energy based distributed generators in the presence of dispatchable distributed generation. The proposed optimization algorithm aims to minimize the energy loss in unbalanced distribution systems by determining the optimal locations of non-dispatchable distributed generators and the optimal hourly power schedule of dispatchable distributed generators. The proposed algorithms are implemented in MATLAB environment and tested on the IEEE 37-node feeder. Several case studies are done and the subsequent discussions show the effectiveness of the proposed algorithms.

A.Y. Abdelaziz; Y.G. Hegazy; Walid El-Khattam; M.M. Othman

2015-01-01T23:59:59.000Z

349

Generally covariant model of a scalar field with high frequency dispersion and the cosmological horizon problem  

E-Print Network (OSTI)

Short distance structure of spacetime may show up in the form of high freqency dispersion. Although such dispersion is not locally Lorentz invariant, we show in a scalar field model how it can nevertheless be incorporated into a generally covariant metric theory of gravity provided the locally preferred frame is dynamical. We evaluate the resulting energy-momentum tensor and compute its expectation value for a quantum field in a thermal state. The equation of state differs at high temperatures from the usual one, but not by enough to impact the problems of a hot big bang cosmology. We show that a superluminal dispersion relation can solve the horizon problem via superluminal equilibration, however it cannot do so while remaining outside the Planck regime unless the dispersion relation is artificially chosen to have a rather steep dependence on wavevector.

Ted Jacobson; David Mattingly

2000-09-11T23:59:59.000Z

350

G-Bounce Inflation: Towards Nonsingular Inflation Cosmology with Galileon Field  

E-Print Network (OSTI)

We study a nonsingular bounce inflation model, which can drive the early universe from a contracting phase, bounce into an ordinary inflationary phase, followed by the reheating process. Besides the bounce that avoided the Big-Bang singularity which appears in the standard cosmological scenario, we make use of the Horndesky theory and design the kinetic and potential forms of the lagrangian, so that neither of the two big problems in bouncing cosmology, namely the ghost and the anisotropy problems, will appear. The cosmological perturbations can be generated either in the contracting phase or in the inflationary phase, where in the latter the power spectrum will be scale-invariant and fit the observational data, while in the former the perturbations will have nontrivial features that will be tested by the large scale structure experiments. We also fit our model to the CMB TT power spectrum.

Qiu, Taotao

2015-01-01T23:59:59.000Z

351

Investigation of rare particle production in high energy nuclear collisions. Progress report, December 15, 1997--December 14, 1998  

SciTech Connect

The program is an investigation of the hadronization process through experimental measurement of rare particle production in high energy nuclear interactions. These interactions provide an environment similar in energy density to the conditions in the Big Bang. The authors are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. They have completed the first physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. They have prototyped the STAR trigger and are in the process of fabricating its components and installing them in the STAR detector.

Crawford, H.J.; Engelage, J.

1998-11-01T23:59:59.000Z

352

Protein folding and cosmology  

E-Print Network (OSTI)

Protein denaturing induced by supercooling is interpreted as a process where some or all internal symmetries of the native protein are spontaneously broken. Hence, the free-energy potential corresponding to a folding-funnel landscape becomes temperature-dependent and describes a phase transition. The idea that deformed vortices could be produced in the transition induced by temperature quenching, from native proteins to unfolded conformations is discussed in terms of the Zurek mechanism that implements the analogy between vortices, created in the laboratory at low energy, and the cosmic strings which are thought to have been left after symmetry breaking phase transitions in the early universe. An experiment is proposed to test the above idea which generalizes the cosmological analogy to also encompass biological systems and push a step ahead the view that protein folding is a biological equivalent of the big bang.

P. F. Gonzalez-Diaz; C. L. Siguenza

1997-06-04T23:59:59.000Z

353

Thermodynamics of the Transformation of Gravitational Waves into Matter Quantums for a Vacuum Space Model  

E-Print Network (OSTI)

It is shown that the entropy of low density monochromatic gravitational waves, waves required for the stabilization of the crystalline structure of vacuum cosmic space, varies with the volume in the same manner as the entropy of an ideal gas formed by particles. This implies that close enough to the big-bang event the energy of all the 10 to the 120 power gravitational waves, under an adiabatic compression process, which stabilizes the crystalline structure of vacuum space behaves thermodynamically as though it is consisted of a number nB = 10 to the 80 power of independent energy or matter quanta (neutrons). PACS numbers: 03.50.De, 03.65.-w, 04.20.-q, 61.50.-f, 65.50.+m, 98.80.Ft, 97.60.Lf

J. A. Montemayor-Aldrete; M. Lopez de Haro; J. R. Morones-Ibarra; A. Morales-Mori; Mendoza-Allende; E. Cabrera-Bravo; A. Montemayor-Varela

2005-09-06T23:59:59.000Z

354

Energy density fluctuations in Early Universe  

E-Print Network (OSTI)

The primordial nucleosinthesys of the element can be influenced by the transitions of phase that take place after the Big Bang, such as the QCD transition. In order to study the effect of this phase transition, in this work we compute the time evolution of thermodynamical quantities of the early universe, focusing on temperature and energy density fluctuations, by solving the relevant equations of motion using as input the lattice QCD equation of state to describe the strongly interacting matter in the early universe plasma. We also study the effect of a primordial strong magnetic field by means of a phenomenological equation of state. Our results show that small inhomogeneities of strongly interacting matter in the early Universe are moderately damped during the crossover.

Guardo, G L; Ruggieri, M

2014-01-01T23:59:59.000Z

355

Doppler-like effect and doubtful expansion of universe  

E-Print Network (OSTI)

The distance contraction, as observed in electrical soundings over horizontally stratified earth (static system), is identified as a counterpart of Doppler shift in dynamical systems. Identification of Doppler-like effect in a stock-still systems makes it possible to give an al-ternative answer to the question about an effective cause of the Doppler shift, which sounds: the inhomogeneities. This answer opens different static as well as kinematic possibilities, which challenge established theories of expanding universe and energizing big bang.The energy propagating in stratified universe of layers exhibits a shift which could be at-tributed not only to the expansion (Hubble's theory) but alternatively to fluctuations in material properties (inhomogeneities).

Edward Szaraniec

2003-10-01T23:59:59.000Z

356

Island Cosmology in the Landscape  

E-Print Network (OSTI)

In the eternally inflationary background driven by the metastable vacua of the landscape, it is possible that some local quantum fluctuations with the null energy condition violation can be large enough to stride over the barriers among different vacua, so that create some islands full of radiation in new vacua, and then these emergently thermalized islands will enter into the evolution of standard big bang cosmology. In this paper, we calculate the spectrum of curvature perturbation generated during the emergence of island. We find that generally the spectrum obtained is nearly scale invariant, which can be well related to that of slow roll inflation by a simple duality. This in some sense suggests a degeneracy between their scalar spectra. In addition, we also simply estimate the non-Gaussianity of perturbation, which is naturally large, yet, can lie well in the observational bound. The results shown here indicate that the island emergently thermalized in the landscape can be consistent with our observable universe.

Yun-Song Piao

2008-06-11T23:59:59.000Z

357

Experiment Profile: DAMIC NAME: Dark Matter In CCDs, or DAMIC  

NLE Websites -- All DOE Office Websites (Extended Search)

DAMIC DAMIC NAME: Dark Matter In CCDs, or DAMIC ThE ORIGIN OF ThE NAME: DAMIC searches for dark matter using Charge Coupled Devices. These digital chips register light that gets converted into a digital value a computer can store. WHAT WILL THIS TELL? Everything you see, visible matter, makes up 4 percent of the universe. Dark matter and dark energy make up the rest of the universe. Physicists understand that dark matter acts as an invisible source of gravity, but little more. DAMIC seeks to pinpoint what particles make up dark matter, which will help explain how the universe came to exist. Without the added gravitational attraction of dark matter, stars and galaxies would have never formed. The expansion of the universe after the Big Bang would have dispersed visible

358

The Universe Adventure - Fundamental Particles  

NLE Websites -- All DOE Office Websites (Extended Search)

Fundamental Particles Fundamental Particles Chart of Fundamental Particles All matter in the universe is comprised of fundamental particles. So what exactly makes up this matter? All matter is made of fundamental particles that came into being at the birth of the Universe. Quarks experience the strong force which is carried by massless particles called gluons. They bond together in specific combinations to form protons, neutrons, and other hadrons. Leptons do not experience the strong force but may interact via the electromagnetic force, the weak force, or both. Anti-quarks and anti-leptons are exactly the same as their quark and lepton counterparts, but have an opposite charge. All massive particles are influenced by the force of gravity. Quark-Gluon Plasma: 10-12 Seconds After the Big Bang

359

Inquiring Minds - Questions About Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics of the universe Physics of the universe From the big bang to black holes, extra dimensions, space and time Centrifugal Force From smaller than atoms to larger than galaxies structures spin and in doing so the centrifugal force throws things outward. Might not the Universe as a whole be spinning on an axis and what we currently ascribe to a mysterious repulsive force be a centrifugal force throwing things outward? Thrown out rather than pushed or drawn? Motion in the Universe I have been attempting to calculate the speed at which an individual is traveling through the universe when standing 'still'. i.e., the rotation speed of the earth, the speed of the orbit of the earth around the sun, the solar system withing our galaxy, the galaxy...etc. Is there such a measurement or 'thing' as absolute STILL?

360

microwaverpp.dvi  

NLE Websites -- All DOE Office Websites (Extended Search)

microwave microwave background 1 26. COSMIC MICROWAVE BACKGROUND Revised September 2013 by D. Scott (University of British Columbia) and G.F. Smoot (UCB/LBNL). 26.1. Introduction The energy content in radiation from beyond our Galaxy is dominated by the cosmic microwave background (CMB), discovered in 1965 [1]. The spectrum of the CMB is well described by a blackbody function with T = 2.7255 K, this spectral form being one of the main pillars of the hot Big Bang model for the early Universe. The lack of any observed deviations from a blackbody spectrum constrains physical processes over cosmic history at redshifts z ∼ < 10 7 (see earlier versions of this review). All viable cosmological models predict a very nearly Planckian spectrum inside the current observational limits (although that could change with more sensitive spectral experiments in the future [2]). Currently the key CMB observable

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361

Energy Blog | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

9, 2013 9, 2013 VIDEO: Watch the Solar Decathlon 2013 Google+ Hangout Miss the Solar Decathlon 2013 Google+ Hangout? Watch a recording of it now. September 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 how three Energy Department National Labs are collaborating to peer deeper into the origins of our universe than ever before. September 19, 2013 Innovating to Meet the Evolving Cyber Challenge Protecting the critical energy infrastructure that supports America's economy and security is vital -- and is a top Energy Department priority. September 17, 2013 An Update on Fisker Automotive and the Energy Department's Loan Portfolio The continued success of America's auto industry depends on innovation

362

Exploring a matter-dominated model with bulk viscosity to drive the accelerated expansion of the Universe  

SciTech Connect

We explore the viability of a bulk viscous matter-dominated Universe to explain the present accelerated expansion of the Universe. The model is composed by a pressureless fluid with bulk viscosity of the form ? = ?{sub 0}+?{sub 1}H where ?{sub 0} and ?{sub 1} are constants and H is the Hubble parameter. The pressureless fluid characterizes both the baryon and dark matter components. We study the behavior of the Universe according to this model analyzing the scale factor as well as some curvature scalars and the matter density. On the other hand, we compute the best estimated values of ?{sub 0} and ?{sub 1} using the type Ia Supernovae (SNe Ia) probe. We find that from all the possible scenarios for the Universe, the preferred one by the best estimated values of (?{sub 0},?{sub 1}) is that of an expanding Universe beginning with a Big-Bang, followed by a decelerated expansion at early times, and with a smooth transition in recent times to an accelerated expansion epoch that is going to continue forever. The predicted age of the Universe is a little smaller than the mean value of the observational constraint coming from the oldest globular clusters but it is still inside of the confidence interval of this constraint. A drawback of the model is the violation of the local second law of thermodynamics in redshifts z?>1. However, when we assume ?{sub 1} = 0, the simple model ? = ?{sub 0} evaluated at the best estimated value for ?{sub 0} satisfies the local second law of thermodynamics, the age of the Universe is in perfect agreement with the constraint of globular clusters, and it also has a Big-Bang, followed by a decelerated expansion with the smooth transition to an accelerated expansion epoch in late times, that is going to continue forever.

Avelino, Arturo; Nucamendi, Ulises, E-mail: avelino@ifm.umich.mx, E-mail: ulises@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, CP. 58040, Morelia, Michoacán (Mexico)

2010-08-01T23:59:59.000Z

363

NEW DETERMINATION OF THE {sup 13}C({alpha}, n){sup 16}O REACTION RATE AND ITS INFLUENCE ON THE s-PROCESS NUCLEOSYNTHESIS IN AGB STARS  

SciTech Connect

We present a new measurement of the {alpha}-spectroscopic factor (S{sub {alpha}}) and the asymptotic normalization coefficient for the 6.356 MeV 1/2{sup +} subthreshold state of {sup 17}O through the {sup 13}C({sup 11}B, {sup 7}Li){sup 17}O transfer reaction and we determine the {alpha}-width of this state. This is believed to have a strong effect on the rate of the {sup 13}C({alpha}, n){sup 16}O reaction, the main neutron source for slow neutron captures (the s-process) in asymptotic giant branch (AGB) stars. Based on the new width we derive the astrophysical S-factor and the stellar rate of the {sup 13}C({alpha}, n){sup 16}O reaction. At a temperature of 100 MK, our rate is roughly two times larger than that by Caughlan and Fowler and two times smaller than that recommended by the NACRE compilation. We use the new rate and different rates available in the literature as input in simulations of AGB stars to study their influence on the abundances of selected s-process elements and isotopic ratios. There are no changes in the final results using the different rates for the {sup 13}C({alpha}, n){sup 16}O reaction when the {sup 13}C burns completely in radiative conditions. When the {sup 13}C burns in convective conditions, as in stars of initial mass lower than {approx}2 M{sub Sun} and in post-AGB stars, some changes are to be expected, e.g., of up to 25% for Pb in our models. These variations will have to be carefully analyzed when more accurate stellar mixing models and more precise observational constraints are available.

Guo, B.; Li, Z. H.; Li, Y. J.; Su, J.; Yan, S. Q.; Bai, X. X.; Chen, Y. S.; Fan, Q. W.; Jin, S. J.; Li, E. T.; Li, Z. C.; Lian, G.; Liu, J. C.; Liu, X.; Shu, N. C. [China Institute of Atomic Energy, P.O. Box 275(1), Beijing 102413 (China); Lugaro, M.; Buntain, J. [Monash Centre for Astrophysics, Monash University, Clayton 3800, Victoria (Australia); Pang, D. Y. [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Karakas, A. I. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Weston Creek ACT 2611 (Australia); Shi, J. R., E-mail: wpliu@ciae.ac.cn, E-mail: guobing@ciae.ac.cn [National Astronomical Observatories, Chinese Academy of Science, Beijing 100012 (China); and others

2012-09-10T23:59:59.000Z

364

64Cu-1,4,7-Triazacyclononane-1,4-diacetic acid-6-aminohexanoic acid-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2  

E-Print Network (OSTI)

. recently reported that the NOTA-based 64Cu-NOTA-8-Aoc-BBN(7­14) NH2 conjugate (where 8-Aoc = 8 pharmacokinetic properties of the 64Cu-NOTA-8-Aoc-BBN(7­14)NH2 conjugate, Lane et al. synthesized a new group of conjugates with the NOTA derivative NO2A and replaced the spacer 8-Aoc with an aliphatic or aromatic linking

Levin, Judith G.

365

64Cu-1,4,7-Triazacyclononane-1,4-diacetic acid-9-aminonanoic acid-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2  

E-Print Network (OSTI)

. recently reported that the NOTA-based 64Cu-NOTA-8-Aoc-BBN(7­14) NH2 conjugate (where 8-Aoc = 8 pharmacokinetic properties of the 64Cu-NOTA-8-Aoc-BBN(7­14)NH2 conjugate, Lane et al. synthesized a new group of conjugates with the NOTA derivative NO2A and replaced the spacer 8-Aoc with an aliphatic or aromatic linking

Levin, Judith G.

366

CRD Report  

E-Print Network (OSTI)

of supernovae, gamma ray bursts and nucleosynthesis. “HighBlack Holes to Gamma Ray Bursts. ” A book launch party is

Wang, Ucilia

2006-01-01T23:59:59.000Z

367

SNAP  

NLE Websites -- All DOE Office Websites (Extended Search)

Mission Home Page Mission Home Page - Spacecraft / Instruments - Science - E/PO - People cutaway image of SNAP The Universe is a big place... and it's getting bigger every day. Our current model of the Universe, called the Big Bang Model, is that the Universe originated approximately 13.7 billion years ago and has been expanding ever since. It was always assumed that expansion was slowing, with the gravity of the Universe itself applying the brakes. But shortly before the end of the 20th century astronomers got a big surprise: the Universe was not slowing down, it was speeding up, the expansion ever accelerating. Very little is known about this accelerated expansion, and less is known about its cause. The SuperNova Acceleration Probe, or SNAP, will fill the wide gaps in our knowledge. It will study exploding stars called supernovae, as well as the gentle smearing of the light from distant galaxies due to gravity - called weak gravitational lensing - and put limits on what may or may not be the force driving the outward pull on the Universe. SNAP will investigate over one thousand square degrees of sky - more than 5000 times the size of the full Moon! - with a 500 megapixel camera.

368

SNAP  

NLE Websites -- All DOE Office Websites (Extended Search)

Expansion Discovered Expansion Discovered - The Big Bang, Modified - Dark Energy - How Will SNAP do it? - Why Do This From Space? - Why Do We Want to Know? - Detailed Overview - Spacecraft / Instruments - Resources Dark Energy Expansion Discovered Astronomers in the early 20th Century got the shocks of their lives when they discovered that galaxies appeared to be rushing away from us. They did this by taking spectra of the galaxies, and then measuring the shift in their spectrum due to their motion. diagram of red shift from astronomynotes.com Credit: Astronomynotes.com You're probably already familiar with this phenomenon, called the Doppler Shift -it's the same principle that makes a car horn change in pitch from high to low as it approaches and passes you. The sound waves are compressed as the car approaches you (resulting in a higher pitch) and are stretched as it recedes (which lowers the pitch). With light, an object approaching you has its light waves compressed, shortening the wavelength. This is called a blue shift ("blue" in this sense doesn't necessarily mean the object gets bluer; astronomers the word as a kind of shorthand, since in visible light the shorter wavelengths are blue). If the object is moving away, the wavelengths are stretched, resulting in a red shift of the spectrum.

369

Special Event/Tour Detail: Ask-a-Scientist Guided Tour of Fermilab  

NLE Websites -- All DOE Office Websites (Extended Search)

Special Event/Tour Detail: Ask-a-Scientist Guided Tour of Fermilab Special Event/Tour Detail: Ask-a-Scientist Guided Tour of Fermilab Tour Info Public Tours Registrar Calendar Special Event/Tours Audience: Public, Teachers, Students, Grades 6 - Adult Description: Take science questions straight to experts. Physicists answer questions and explain everything from the Big Bang to how a particle accelerator works. Ask a Scientist is held from 1 PM to 4 PM on the first Sunday of the month (except holiday weekends when we delay by one week and in the month of the Family Open House). Each three-hour session includes a presentation by a scientist, a tour, and a Q & A period. The docent-led tour includes visiting the 1st and 15th floor of Wilson Hall, the Linac building with the first two accelerators, the neutron therapy area and the Main Control Room. There is no charge for the session, but advance registration is required. The minimum age for the tour is 10 years old. No exceptions.

370

Falsification of dark energy by fluid mechanics  

E-Print Network (OSTI)

The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies and merge to form their stars. Dark energy is a systematic dimming error for Supernovae Ia caused by dark matter planets near hot white dwarf stars at the Chandrasekhar carbon limit. Evaporated planet atmospheres may or may not scatter light from the events depending on the line of sight.

Carl H. Gibson

2012-03-23T23:59:59.000Z

371

Probing Neutrino Dark Energy with Extremely High-Energy Cosmic Neutrinos  

E-Print Network (OSTI)

Recently, a new non-Standard Model neutrino interaction mediated by a light scalar field was proposed, which renders the big-bang relic neutrinos of the cosmic neutrino background a natural dark energy candidate, the so-called Neutrino Dark Energy. As a further consequence of this interaction, the neutrino masses become functions of the neutrino energy densities and are thus promoted to dynamical, time/redshift dependent quantities. Such a possible neutrino mass variation introduces a redshift dependence into the resonance energies associated with the annihilation of extremely high-energy cosmic neutrinos on relic anti-neutrinos and vice versa into Z-bosons. In general, this annihilation process is expected to lead to sizeable absorption dips in the spectra to be observed on earth by neutrino observatories operating in the relevant energy region above 10^13 GeV. In our analysis, we contrast the characteristic absorption features produced by constant and varying neutrino masses, including all thermal background effects caused by the relic neutrino motion. We firstly consider neutrinos from astrophysical sources and secondly neutrinos originating from the decomposition of topological defects using the appropriate fragmentation functions. On the one hand, independent of the nature of neutrino masses, our results illustrate the discovery potential for the cosmic neutrino background by means of relic neutrino absorption spectroscopy. On the other hand, they allow to estimate the prospects for testing its possible interpretation as source of Neutrino Dark Energy within the next decade by the neutrino observatories ANITA and LOFAR.

Andreas Ringwald; Lily Schrempp

2006-06-13T23:59:59.000Z

372

Static Universe: Infinite, Eternal and Self-Sustainable  

E-Print Network (OSTI)

In this work, we present a study like a "stellar dynamics" model of an infinite Universe, in which the matter distribution follow a relationship inversely proportional to the square power with respect to the distance from the center of rotation of cluster and supercluster of galaxies (that have a common centre of rotation). In this study, we considered that the Universe have infinite centers similar in structure and in dynamic equilibrium between them. The stars in the galaxies are supposed to be homogeneously distributed with a spherical symmetry and with an average radius and, in turn, the galaxies in the Universe. Also, we consider a smoothed potential of this kind of universe and study the effect of gravity in the radiation of the stars: applying the equivalence principle we obtain a mathematical expression for the Hubble's law and a formula for its redshift that could explain this phenomenon like a gravitational effect. Also we obtain an approximated calculation of the Cosmic Background Radiation (CBR), taking as hypothesis that this radiation is the light of all stars in the Universe that arrive until us with an extreme gravitational redshift. In conclusion, we present here an alternative explanation for the redshift and CBR, like an alternative to the presented by the Big Bang theory, or Steady State theory, postulating in consequence a new theory about the structure of the Universe: static, infinite, eternal and self-sustainable.

E. Lopez Sandoval

2012-06-25T23:59:59.000Z

373

Le LHC, un tunnel cosmique  

ScienceCinema (OSTI)

Et si la lumière au bout du tunnel du LHC était cosmique ? En d?autres termes, qu?est-ce que le LHC peut nous apporter dans la connaissance de l?Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l?univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l?Univers ? La matière noire est-elle détectable au LHC ? L?énergie noire ? Pourquoi l?antimatière accumulée au CERN est-elle si rare dans l?Univers ? Et si le CERN a bâti sa réputation sur l?exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l?évolution cosmique ? Depuis une trentaine d?années, notre compréhension de l?univers dans ses plus grandes dimensions et l?appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

None

2011-10-06T23:59:59.000Z

374

Cosmic Perturbations Through the Cyclic Ages  

E-Print Network (OSTI)

We analyze the evolution of cosmological perturbations in the cyclic model, paying particular attention to their behavior and interplay over multiple cycles. Our key results are: (1) galaxies and large scale structure present in one cycle are generated by the quantum fluctuations in the preceding cycle without interference from perturbations or structure generated in earlier cycles and without interfering with structure generated in later cycles; (2) the ekpyrotic phase, an epoch of gentle contraction with equation of state $w\\gg 1$ preceding the hot big bang, makes the universe homogeneous, isotropic and flat within any given observer's horizon; and, (3) although the universe is uniform within each observer's horizon, the global structure of the cyclic universe is more complex, owing to the effects of superhorizon length perturbations, and cannot be described in a uniform Friedmann-Robertson-Walker picture. In particular, we show that the ekpyrotic phase is so effective in smoothing, flattening and isotropizing the universe within the horizon that this phase alone suffices to solve the horizon and flatness problems even without an extended period of dark energy domination (a kind of low energy inflation). Instead, the cyclic model rests on a genuinely novel, non-inflationary mechanism (ekpyrotic contraction) for resolving the classic cosmological conundrums.

Joel K. Erickson; Steven Gratton; Paul J. Steinhardt; Neil Turok

2006-07-23T23:59:59.000Z

375

On the ultra high energy cosmic rays and the origin of the cosmic microwave background radiation  

E-Print Network (OSTI)

Some inconsistencies to the assumption of a cosmological origin of the cosmic microwave background CMB, such as the absence of gravitational lensing in the WMAP data, open the doors to some speculations such as a local origin to the CMB. We argue here that this assumption agrees with the absence of the GZK cutoff (at least according to AGASA data) in the energy spectrum of the cosmic ray due to the cosmic interaction with the CMB at $6\\times 10^{19} eV$ or above. Within 50 Mpc from Earth, the matter and light distributions are close to an anisotropic distribution, where the local cluster and local super-clusters of galaxies can be identified. In contrast, the ultra high energy comic rays data is consistent to an almost isotropic distribution, and there is no correlation between their arrival direction and astronomical sources within our local cluster. This means that the events above the GZK cutoff come from distances above 50 Mpc, without an apparent energy loss. This scenario is plausible under the assumption of the CMB concentrated only within 3-4 Mpc from Earth. In other words, the CMB has a local origin linked only to the local super-cluster of galaxies. In addition, the galactic and extragalactic energy spectra index within the energy equipartition theorem strongly constrains the dark matter and dark energy hypothesis, essential in the Big Bang cosmology.

C. E. Navia; C. R. A. Augusto; K. H. Tsui

2007-07-12T23:59:59.000Z

376

Primordial Magnetic Field Effects on the CMB and Large Scale Structure  

E-Print Network (OSTI)

Magnetic fields are everywhere in nature and they play an important role in every astronomical environment which involves the formation of plasma and currents. It is natural therefore to suppose that magnetic fields could be present in the turbulent high temperature environment of the big bang. Such a primordial magnetic field (PMF) would be expected to manifest itself in the cosmic microwave background (CMB) temperature and polarization anisotropies, and also in the formation of large- scale structure. In this review we summarize the theoretical framework which we have developed to calculate the PMF power spectrum to high precision. Using this formulation, we summarize calculations of the effects of a PMF which take accurate quantitative account of the time evolution of the cut off scale. We review the constructed numerical program, which is without approximation, and an improvement over the approach used in a number of previous works for studying the effect of the PMF on the cosmological perturbations. We demonstrate how the PMF is an important cosmological physical process on small scales. We also summarize the current constraints on the PMF amplitude $B_\\lambda$ and the power spectral index $n_B$ which have been deduced from the available CMB observational data by using our computational framework.

Dai G. Yamazaki; Kiyotomo Ichiki; Toshitaka Kajino; Grant J. Mathew

2011-12-21T23:59:59.000Z

377

The Premature Formation of High Redshift Galaxies  

E-Print Network (OSTI)

Observations with WFC3/IR on the Hubble Space Telescope and the use of gravitational lensing techniques have facilitated the discovery of galaxies as far back as z ~ 10-12, a truly remarkable achievement. However, this rapid emergence of high-z galaxies, barely ~ 200 Myr after the transition from Population III star formation to Population II, appears to be in conflict with the standard view of how the early Universe evolved. This problem has much in common with the better known (and probably related) premature appearance of supermassive black holes at z ~ 6. It is difficult to understand how ~ 10^9 solar-mass black holes could have appeared so quickly after the big bang without invoking non-standard accretion physics and the formation of massive seeds, neither of which is seen in the local Universe. In earlier work, we showed that the appearance of high-z quasars could instead be understood more reasonably in the context of the R_h=ct Universe, which does not suffer from the same time compression issues as L...

Melia, Fulvio

2014-01-01T23:59:59.000Z

378

Macroscopic theory of dark sector  

E-Print Network (OSTI)

A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant. Massive fields {\\phi}_{I} with {\\phi}^{K}{\\phi}_{K}0 describe two different forms of dark matter. The space-like ({\\phi}^{K}{\\phi}_{K}0) massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating non-singular scenarios of evolution of the universe. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerate expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution is a particular limiting case at the boundary of existence of regular oscillating solutions in the absence of vector fields. The simplicity of the general covariant expression for the energy-momentum tensor allows to display the main properties of the dark sector analytically and avoid unnecessary model assumptions.

Boris E. Meierovich

2014-10-06T23:59:59.000Z

379

Confronting the relaxation mechanism for a large cosmological constant with observations  

E-Print Network (OSTI)

In order to deal with a large cosmological constant a relaxation mechanism based on modified gravity has been proposed recently. By virtue of this mechanism the effect of the vacuum energy density of a given quantum field/string theory (no matter how big is its initial value in the early universe) can be neutralized dynamically, i.e. without fine tuning, and hence a Big Bang-like evolution of the cosmos becomes possible. Remarkably, a large class F^n_m of models of this kind, namely capable of dynamically adjusting the vacuum energy irrespective of its value and size, has been identified. In this paper, we carefully put them to the experimental test. By performing a joint likelihood analysis we confront these models with the most recent observational data on type Ia supernovae (SNIa), the Cosmic Microwave Background (CMB), the Baryonic Acoustic Oscillations (BAO) and the high redshift data on the expansion rate, so as to determine which ones are the most favored by observations. We compare the optimal relaxation models F^n_m found by this method with the standard or concordance LambdaCDM model, and find that some of these models may appear as almost indistinguishable from it. Interestingly enough, this shows that it is possible to construct viable solutions to the tough cosmological fine tuning problem with models that display the same basic phenomenological features as the concordance model.

Spyros Basilakos; Florian Bauer; Joan Sola

2012-01-03T23:59:59.000Z

380

Is Hubble's Expansion due to Dark Energy  

E-Print Network (OSTI)

{\\it The universe is expanding} is known (through Galaxy observations) since 1929 through Hubble's discovery ($V = H D$). Recently in 1999, it is found (through Supernovae observations) that the universe is not simply expanding but is accelerating too. We, however, hardly know only $4\\%$ of the universe. The Wilkinson Microwave Anisotropy Probe (WMAP) satellite observational data suggest $73\\%$ content of the universe in the form of dark-energy, $23\\%$ in the form of non-baryonic dark-matter and the rest $4\\%$ in the form of the usual baryonic matter. The acceleration of the universe is ascribed to this dark-energy with bizarre properties (repulsive-gravity). The question is that whether Hubble's expansion is just due to the shock of big-bang & inflation or it is due to the repulsive-gravity of dark-energy? Now, it is believed to be due to dark-energy, say, by re-introducing the once-discarded cosmological-constant $\\Lambda$. In the present paper, it is shown that `the formula for acceleration due to dark-energy' is (almost) exactly of same-form as `the acceleration formula from the Hubble's law'. Hence, it is concluded that: yes, `indeed it is the dark-energy responsible for the Hubble's expansion too, in-addition to the current on-going acceleration of the universe'.

R. C. Gupta; Anirudh Pradhan

2010-10-19T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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381

Observational evidence favors a static universe  

E-Print Network (OSTI)

The common attribute of all Big Bang cosmologies is that they are based on the assumption that the universe is expanding. However examination of the evidence for this expansion clearly favours a static universe. The major topics considered are: Tolman surface brightness, angular size, type 1a supernovae, gamma ray bursts, galaxy distributions, quasar distributions, X-ray background radiation, cosmic microwave background radiation, radio source counts, quasar variability and the Butcher--Oemler effect. An analysis of the best raw data for these topics shows that they are consistent with expansion only if there is evolution that cancels the effects of expansion. An alternate cosmology, curvature cosmology, is in full agreement with the raw data. This tired-light cosmology predicts a well defined static and stable universe and is fully described. It not only predicts accurate values for the Hubble constant and the temperature of cosmic microwave background radiation but shows excellent agreement with most of the topics considered. Curvature cosmology also predicts the deficiency in solar neutrino production rate and can explain the anomalous acceleration of {\\it Pioneer} 10.

David F. Crawford

2014-07-09T23:59:59.000Z

382

The origin of matter and structure in the universe  

E-Print Network (OSTI)

Cosmology is nowadays going through a true revolution in the quantity and quality of observations that are capable of providing crucial information about the origin and evolution of the universe. In the first years of the next millenium we will have, for the first time in the history of cosmology, a precise knowledge about a handful of parameters that determine our Standard Cosmological Model. This standard model is based on the inflationary paradigm, a period of exponential expansion in the early universe responsible for the large scale homogeneity and flatness of our observable patch of the universe. A spectrum of density perturbations, seen in the microwave background as temperature anisotropies, could have been produced during inflation from quantum fluctuations that were stretched to cosmological size by the expansion, and later gave rise, via gravitational collapse, to the observed large scale structure of clusters and superclusters of galaxies. Furthermore, the same theory predicts that all the matter and radiation in the universe today originated at the end of inflation from an explosive production of particles that could also have been the origin of the present baryon asymmetry, before the universe reached thermal equilibrium at a very large temperature. From there on, the universe cooled down as it expanded, in the way described by the standard hot big bang model. With the observations that will soon become available in the next millenium, we will be able to test the validity of the inflationary paradigm, and determine with unprecedented accuracy the parameters of a truly Standard Model of Cosmology.

Juan Garcia-Bellido

1999-06-30T23:59:59.000Z

383

Cosmic rays and tests of fundamental principles  

E-Print Network (OSTI)

It is now widely acknowledged that cosmic rays experiments can test possible new physics directly generated at the Planck scale or at some other fundamental scale. By studying particle properties at energies far beyond the reach of any man-made accelerator, they can yield unique checks of basic principles. A well-known example is provided by possible tests of special relativity at the highest cosmic-ray energies. But other essential ingredients of standard theories can in principle be tested: quantum mechanics, uncertainty principle, energy and momentum conservation, effective space-time dimensions, hamiltonian and lagrangian formalisms, postulates of cosmology, vacuum dynamics and particle propagation, quark and gluon confinement, elementariness of particles... Standard particle physics or string-like patterns may have a composite origin able to manifest itself through specific cosmic-ray signatures. Ultra-high energy cosmic rays, but also cosmic rays at lower energies, are probes of both "conventional" and new Physics. Status, prospects, new ideas, and open questions in the field are discussed. The Post Scriptum shows that several basic features of modern cosmology naturally appear in a SU(2) spinorial description of space-time without any need for matter, relativity or standard gravitation. New possible effects related to the spinorial space-time structure can also be foreseen. Similarly, the existence of spin-1/2 particles can be naturally related to physics beyond Planck scale and to a possible pre-Big Bang era.

Luis Gonzalez-Mestres

2010-11-22T23:59:59.000Z

384

Superconductivity The Structure Scale of the Universe (Twenty Second Edition)  

E-Print Network (OSTI)

A numerical and dimensional correlation supported by literature reported experimental evidence (Homes, Harshman along with Voyager, EGRET, FERMI, WMAP and Planck space platforms and other spacecraft) is presented which indicates that superconductivity is congruent with the Charge Conjugation, Parity Change and Time Reversal (CPT) theorem and scalable with Friedmann Lemaitre Robertson Walker (FLRW) cosmology within the concept of Schwinger pair production and the de Broglie hypothesis. This momentum and energy conserving (elastic) CPT resonant structural lattice is scalable over 15 orders of magnitude from nuclear to universe dimensions, from the universe Big Bang event to present and is consistent with nuclear (quark) weak and strong forces, electromagnetic and gravitational forces being mediated by a particle of constant mass (110.123 x electron mass or 56 MeV/c2) related to the Higgs mass. This isotropic homogeneous CPT structure filling the space vacuum presently defines an extremely cold dark energy condition that dictates an equally extremely cold baryonic dark matter. The model predicts a deceleration value consistent with flat galactic rotation curves and with observed Pioneer 10 and 11 deep space translational and rotational deceleration and is generally consistent with the notion that: An object moving through momentum space will decelerate. This deceleration concept allows Type 1A supernovae universe accelerated expansion data to be interpreted as if the local universe is slowing down with respect to the rest. The entire concept focuses towards engineering a critical optical volume energy (COVE) as a possible energy source.

Richard D. Saam

1999-05-05T23:59:59.000Z

385

High Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z~6 QSOs  

E-Print Network (OSTI)

New measurements of the z~6 intergalactic CIV abundance are presented, using moderate resolution IR spectra of two QSOs taken with GNIRS on Gemini South. These data were systematically searched for high redshift CIV absorption lines, using objective selection criteria. Comprehensive tests were performed to quantify sample incompleteness, as well as the rate of false positive CIV identifications. The trend of constant $\\Omega_{CIV}(z)$ observed at z~2-5 appears to continue to z~6, the highest observed redshift. The CIV sample is also consistent with the redshift-invariant form of the CIV column density distribution reported by Songaila (2001) at lower redshift, although with fairly large uncertainties due to a smaller sample size and noisier infrared data. The constant value of $\\Omega_{CIV}$ does not necessarily imply that the IGM was infused with an early metallicity ``floor,'' but the presence of early CIV does indicate that heavy-element enrichment began < 1 Gyr after the Big Bang. The lack of a decline...

Simcoe, R A

2006-01-01T23:59:59.000Z

386

High Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z~6 QSOs  

E-Print Network (OSTI)

New measurements of the z~6 intergalactic CIV abundance are presented, using moderate resolution IR spectra of two QSOs taken with GNIRS on Gemini South. These data were systematically searched for high redshift CIV absorption lines, using objective selection criteria. Comprehensive tests were performed to quantify sample incompleteness, as well as the rate of false positive CIV identifications. The trend of constant $\\Omega_{CIV}(z)$ observed at z~2-5 appears to continue to z~6, the highest observed redshift. The CIV sample is also consistent with the redshift-invariant form of the CIV column density distribution reported by Songaila (2001) at lower redshift, although with fairly large uncertainties due to a smaller sample size and noisier infrared data. The constant value of $\\Omega_{CIV}$ does not necessarily imply that the IGM was infused with an early metallicity ``floor,'' but the presence of early CIV does indicate that heavy-element enrichment began < 1 Gyr after the Big Bang. The lack of a decline in $\\Omega_{CIV}$ at high redshift may indicate that integrated CIV measurements are sensitive to the instantaneous rate of feedback from galaxy formation at each epoch. Alternatively, it could result from a balance in the evolution of the intergalactic gas density, ionization conditions, and heavy-element abundance over time.

Robert A. Simcoe

2006-05-30T23:59:59.000Z

387

The Shape and Flow of Heavy Ion Collisions (490th Brookhaven Lecture)  

SciTech Connect

The sun can’t do it, but colossal machines like the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab and Large Hadron Collider (LHC) in Europe sure can. Quarks and gluons make up protons and neutrons found in the nucleus of every atom in the universe. At heavy ion colliders like RHIC and the LHC, scientists can create matter more than 100,000 times hotter than the center of the sun—so hot that protons and neutrons melt into a plasma of quarks and gluons. The particle collisions and emerging quark-gluon plasma hold keys to understanding how these fundamental particles interact with each other, which helps explain how everything is held together—from atomic nuclei to human beings to the biggest stars—how all matter has mass, and what the universe looked like microseconds after the Big Bang. Dr. Schenke discusses theory that details the shape and structure of heavy ion collisions. He will also explain how this theory and data from experiments at RHIC and the LHC are being used to determine properties of the quark-gluon plasma.

Schenke, Bjoern [BNL Physics Department

2014-12-18T23:59:59.000Z

388

Non-commutative geometry as a realization of varying speed of light cosmology  

E-Print Network (OSTI)

We examine the cosmological implications of space-time non-commutativity, discovering yet another realization of the varying speed of light model. Our starting point is the well-known fact that non-commutativity leads to deformed dispersion relations, relating energy and momentum, implying a frequency dependent speed of light. A Hot Big Bang Universe therefore experiences a higher speed of light as it gets hotter. We study the statistical physics of this "deformed radiation", recovering standard results at low temperatures, but a number of novelties at high temperatures: a deformed Planck's spectrum, a temperature dependent equation of state $w=p/\\rho$ (ranging from 1/3 to infinity), a new Stephan-Boltzmann law, and a new entropy relation. These new photon properties closely mimic those of phonons in crystals, hardly a surprising analogy. They combine to solve the horizon and flatness problems, explaining also the large entropy of the Universe. We also show how one would find a direct imprint of non-commutativity in the spectrum of a cosmic graviton background, should it ever be detected.

Stephon H. S. Alexander; João Magueijo

2001-04-10T23:59:59.000Z

389

"Title","Creator/Author","Publication Date","OSTI Identifier...  

Office of Scientific and Technical Information (OSTI)

(NNSA); USDOE Office of Science (SC)","79 - ASTRONOMY AND ASTROPHYSICS Supernovae; Gamma Ray Bursts; Nucleosynthesis; SciDAC; Scientific Discovery through Advanced...

390

E-Print Network 3.0 - aspherical core-collapse supernovae Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

supernovae: New challenges and perspectives 12;Outline Introduction... Gamma-ray bursts Nucleosynthesis, etc.. Up to now only SN1987A TAMA300 Core-collapse Supernovae...

391

E-Print Network 3.0 - astrophysics gravitational waves Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

position in astrophysics 3D supercomputer simulation of the formation Summary: , Gamma-ray bursts, nucleosynthesis, sources of gravitational waves and computational methods....

392

TITLE AUTHORS SUBJECT SUBJECT RELATED DESCRIPTION PUBLISHER AVAILABILI...  

Office of Scientific and Technical Information (OSTI)

Stan University of California Santa Cruz ASTRONOMY AND ASTROPHYSICS Supernovae Gamma Ray Bursts Nucleosynthesis SciDAC Scientific Discovery through Advanced Computing...

393

Energy geothermal; San Emidio Geothermal Area; 3D Model geothermal...  

Office of Scientific and Technical Information (OSTI)

(University of California, Santa Cruz) 79 - ASTRONOMY AND ASTROPHYSICS Supernovae; Gamma Ray Bursts; Nucleosynthesis; SciDAC; Scientific Discovery through Advanced Computing...

394

Laser-Compton backscattering for nuclear astrophysics  

SciTech Connect

Using ?-ray beams for experimental nucleosynthesis study forms a new branch of nuclear astrophysics. I introduce typical experimental investigations and give a future prospect of this branch.

Utsunomiya, Hiroaki [Department of Physics, Konan University, 8-9-1, Okamoto, Higashinada, Kobe 658-85-1, Japan and The Center for Nuclear Study, University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2014-05-09T23:59:59.000Z

395

A Bayesian Belief Network of Threat Anticipation and Terrorist Motivations  

SciTech Connect

Recent events highlight the need for efficient tools for anticipating the threat posed by terrorists, whether individual or groups. Antiterrorism includes fostering awareness of potential threats, deterring aggressors, developing security measures, planning for future events, halting an event in process, and ultimately mitigating and managing the consequences of an event. To analyze such components, one must understand various aspects of threat elements like physical assets and their economic and social impacts. To this aim, we developed a three-layer Bayesian belief network (BBN) model that takes into consideration the relative threat of an attack against a particular asset (physical layer) as well as the individual psychology and motivations that would induce a person to either act alone or join a terrorist group and commit terrorist acts (social and economic layers). After researching the many possible motivations to become a terrorist, the main factors are compiled and sorted into categories such as initial and personal indicators, exclusion factors, and predictive behaviors. Assessing such threats requires combining information from disparate data sources most of which involve uncertainties. BBN combines these data in a coherent, analytically defensible, and understandable manner. The developed BBN model takes into consideration the likelihood and consequence of a threat in order to draw inferences about the risk of a terrorist attack so that mitigation efforts can be optimally deployed. The model is constructed using a network engineering process that treats the probability distributions of all the BBN nodes within the broader context of the system development process.

Olama, Mohammed M [ORNL; Allgood, Glenn O [ORNL; Davenport, Kristen M [ORNL; Schryver, Jack C [ORNL

2010-01-01T23:59:59.000Z

396

A CLASS OF MARKOV PROCESSES ASSOCIATED WITH NONLINEAR PARABOLIC EQUATIONS  

Science Journals Connector (OSTI)

...bI=J [(1 -e-2')]-112eXp[_( a-21- 'm2fda. Now consider a more elaborate problem: au_ 1 62 2 - D*u = 2 a C2U a CIU with coefficients cl and c2 expressible as integrals C = C[UI = fRn c(axbl. . ..bbn)U. . . (u dbl ... dbn...

H. P. McKean; Jr.

1966-01-01T23:59:59.000Z

397

Seminar N 03301, Dynamically  

E-Print Network (OSTI)

Seminar Nº 03301, Dynamically Reconfigurable Architectures A Mead-&-Conway-like Break ·Ametek ·Applied Dynamics ·Astronautics ·BBN ·CDC ·Convex ·Cray Computer ·Cray Research ·Culler-Harris

Hartenstein, Reiner

398

MEMORY MANAGEMENT FOR LARGE-SCALE NUMA MULTIPROCESSORS  

E-Print Network (OSTI)

MEMORY MANAGEMENT FOR LARGE-SCALE NUMA MULTIPROCESSORS Thomas J. LeBlanc Brian D. Marsh Michael L@cs.rochester.edu marsh@cs.rochester.edu scott@cs.rochester.edu March 1989 Abstract Large-scale shared-memory multiprocessors such as the BBN Butterfly and IBM RP3 Introduce a new level In the memory hierarchy: multiple

Scott, Michael L.

399

THE AsntDPHYSiCAL : 294-2^7, 1986 April 1  

E-Print Network (OSTI)

into 22 Nc). Then neutrons are slowed down mainly due to their scattering on 4 Hc (f = Or425, . ENHANCEMENT OF NUCLEOSYNTHESIS REACTION RATES DUE TO NONTHERMALIZED FAST NEUTRONS Yu, V. PETROV AND A. I It is usually assumed in stellar nucleosynthesis calculations that neutrons art completely thcrmalizcd. Hence

Shlyakhter, Ilya

400

Flux  

NLE Websites -- All DOE Office Websites (Extended Search)

5000 5000 6000 7000 8000 Wavelength (Angstroms) Flux (in arbitrary units) SN 1990N SN 1989B SN 1993O SN 1981B SN 1994D SN 1997ap Iron Peak Blends Ca II Si II & Co II Fe II & III Day -7 Day -5 Day -4 Day -2 ± 2 Day 0 Day +2 * -50 0 50 100 150 Observed days from peak Observed I magnitude 27 26 25 24 23 Observed R magnitude 27 26 25 24 Observed I magnitude 27 26 25 24 23 R band Ground-based I band HST I band (b) (c) (a) Pre-SN observation 3.5 4.0 4.5 5.0 5.5 log(cz) 14 16 18 20 22 24 26 effective m B 0.02 0.05 0.1 0.2 0.5 1.0 redshift z Hamuy et al (A.J. 1996) Supernova Cosmology Project 6 8 % 9 0 % 0.5 1.0 1.5 2.0 2.5 3.0 ! M Age < 9.6 Gyr (H = 50 km s -1 Mpc -1 ) No Big Bang 0.0 0.5 1.0 1.5 2.0 2.5 3.0 -3 -2 -1 0 1 2 3 -3 -2 -1 0 1 2 3 ! " z ~ 0 . 4 z = 0 . 8 3 6 8 % 9 0 % 0.5 1.0 1.5 2.0 2.5 3.0 ! M Age < 9.6 Gyr (H=50 km/s/Mpc)

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

eLISA: Astrophysics and cosmology in the millihertz regime  

E-Print Network (OSTI)

This document introduces the exciting and fundamentally new science and astronomy that the European New Gravitational Wave Observatory (NGO) mission (derived from the previous LISA proposal) will deliver. The mission (which we will refer to by its informal name "eLISA") will survey for the first time the low-frequency gravitational wave band (about 0.1 mHz to 1 Hz), with sufficient sensitivity to detect interesting individual astrophysical sources out to z = 15. The eLISA mission will discover and study a variety of cosmic events and systems with high sensitivity: coalescences of massive black holes binaries, brought together by galaxy mergers; mergers of earlier, less-massive black holes during the epoch of hierarchical galaxy and black-hole growth; stellar-mass black holes and compact stars in orbits just skimming the horizons of massive black holes in galactic nuclei of the present era; extremely compact white dwarf binaries in our Galaxy, a rich source of information about binary evolution and about future Type Ia supernovae; and possibly most interesting of all, the uncertain and unpredicted sources, for example relics of inflation and of the symmetry-breaking epoch directly after the Big Bang. eLISA's measurements will allow detailed studies of these signals with high signal-to-noise ratio, addressing most of the key scientific questions raised by ESA's Cosmic Vision programme in the areas of astrophysics and cosmology. They will also provide stringent tests of general relativity in the strong-field dynamical regime, which cannot be probed in any other way. This document not only describes the science but also gives an overview on the mission design and orbits.

Pau Amaro-Seoane; Sofiane Aoudia; Stanislav Babak; Pierre Binétruy; Emanuele Berti; Alejandro Bohé; Chiara Caprini; Monica Colpi; Neil J. Cornish; Karsten Danzmann; Jean-François Dufaux; Jonathan Gair; Oliver Jennrich; Philippe Jetzer; Antoine Klein; Ryan N. Lang; Alberto Lobo; Tyson Littenberg; Sean T. McWilliams; Gijs Nelemans; Antoine Petiteau; Edward K. Porter; Bernard F. Schutz; Alberto Sesana; Robin Stebbins; Tim Sumner; Michele Vallisneri; Stefano Vitale; Marta Volonteri; Henry Ward

2012-01-17T23:59:59.000Z

402

Improving the design and analysis of superconducting magnets for particle accelerators  

SciTech Connect

High energy particle accelerators are now the primary means of discovering the basic building blocks of matter and understanding the forces between them. In order to minimize the cost of building these machines, superconducting magnets are used in essentially all present day high energy proton and heavy ion colliders. The cost of superconducting magnets is typically in the range of 20--30% of the total cost of building such machines. The circulating particle beam goes through these magnets a large number of times (over hundreds of millions). The luminosity performance and life time of the beam in these machines depends significantly on the field quality in these magnets. Therefore, even a small error in the magnetic field shape may create a large cumulative effect in the beam trajectory to throw the particles of the magnet aperture. The superconducting accelerator magnets must, therefore, be designed and constructed so that these errors are small. In this thesis the research and development work will be described 3which has resulted in significant improvements in the field quality of the superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). The design and the field quality improvements in the prototype of the main collider dipole magnet for the Superconducting Super Collider (SSC) will also be presented. RHIC will accelerate and collide two counter rotating beams of heavy ions up to 100 GeV/u and protons up to 250 GeV. It is expected that RHIC will create a hot, dense quark-gluon plasma and the conditions which, according to the Big Bang theory, existed in the early universe.

Gupta, R.C. [Univ. of Rajasthan, Jaipur (India). Dept. of Physics]|[Brookhaven National Lab., Upton, NY (United States). Magnet Div.

1996-11-01T23:59:59.000Z

403

Intensity-Frontier Antiproton Physics with The Antiproton Annihilation Spectrometer (TAPAS) at Fermilab  

SciTech Connect

The Fermilab Antiproton Source is the world's most intense source of antimatter. With the Tevatron program now behind us, this unique facility can help make the case for Fermilab's continued accelerator operations. The Antiproton Source can be used for unique, dedicated antimatter studies, including medium-energy {bar p}-annihilation experiments. We propose to assemble a powerful, yet cost-effective, solenoidal magnetic spectrometer for antiproton-annihilation events, and to use it at the Fermilab Antiproton Accumulator to measure the charm production cross section, study rare hyperon decays, search for hyperon CP asymmetry, precisely measure the properties of several charmonium and nearby states, and make the first measurements of the Drell-Yan continuum in medium-energy antiproton annihilation. Should the charm production cross section be as large as some have proposed, we will also be able to measure D{sup 0}-{bar D}{sup 0} mixing with high precision and discover (or sensitively limit) charm CP violation. The observation of charm or hyperon CP violation would be evidence for physics beyond the Standard Model, with possible implications for the origin of the baryon asymmetry of the universe - the question of what happened to all the antimatter that must have been produced in the Big Bang. The experiment will be carried out by an international collaboration and will require some four years of running time. As possibly the sole hadron experiment in progress at Fermilab during that time, it will play an important role in maintaining a broad particle physics program at Fermilab and in the U.S. It will thus help us to continue attracting creative and capable young people into science and technology, and introducing them to the important technologies of accelerators, detectors, and data acquisition and analysis - key roles in society that accelerator-based particle physics has historically played.

Apollinari, Giorgio; /Fermilab; Asner, David M.; /PNL, Richland; Baldini, Wander; /INFN, Ferrara; Bartoszek, Larry; Broemmelsiek, Daniel R.; Brown, Charles N.; /Fermilab; Chakravorty, Alak; /St. Xavier U., Chicago; Colas, Paul; /Saclay; Derwent, Paul; /Fermilab; Drutskoy, Alexey; /Moscow, ITEP; Fortner, Michael; /Northern Illinois U. /Saclay /Indian Inst. Tech., Hyderabad

2011-11-01T23:59:59.000Z

404

Dark Matter Gravitational Interactions  

E-Print Network (OSTI)

We argue that the conjectured dark mater in the Universe may be endowed with a new kind of gravitational charge that couples to a short range gravitational interaction mediated by a massive vector field. A model is constructed that assimilates this concept into ideas of current inflationary cosmology. The model is also consistent with the observed behaviour of galactic rotation curves according to Newtonian dynamics. The essential idea is that stars composed of ordinary (as opposed to dark matter) experience Newtonian forces due to the presence of an all pervading background of massive gravitationally charged cold dark matter. The novel gravitational interactions are predicted to have a significant influence on pre-inflationary cosmology. The precise details depend on the nature of a gravitational Proca interaction and the description of matter. A gravitational Proca field configuration that gives rise to attractive forces between dark matter charges of like polarity exhibits homogeneous isotropic eternal cosmologies that are free of cosmological curvature singularities thus eliminating the horizon problem associated with the standard big-bang scenario. Such solutions do however admit dense hot pre-inflationary epochs each with a characteristic scale factor that may be correlated with the dark matter density in the current era of expansion. The model is based on a theory in which a modification of Einsteinian gravity at very short distances can be expressed in terms of the gradient of the Einstein metric and the torsion of a non-Riemannian connection on the bundle of linear frames over spacetime. Indeed we demonstrate that the genesis of the model resides in a remarkable simplification that occurs when one analyses the variational equations associated with a broad class of non-Riemannian actions.

R. W. Tucker; C. Wang

1996-12-09T23:59:59.000Z

405

The Premature Formation of High Redshift Galaxies  

E-Print Network (OSTI)

Observations with WFC3/IR on the Hubble Space Telescope and the use of gravitational lensing techniques have facilitated the discovery of galaxies as far back as z ~ 10-12, a truly remarkable achievement. However, this rapid emergence of high-z galaxies, barely ~ 200 Myr after the transition from Population III star formation to Population II, appears to be in conflict with the standard view of how the early Universe evolved. This problem has much in common with the better known (and probably related) premature appearance of supermassive black holes at z ~ 6. It is difficult to understand how ~ 10^9 solar-mass black holes could have appeared so quickly after the big bang without invoking non-standard accretion physics and the formation of massive seeds, neither of which is seen in the local Universe. In earlier work, we showed that the appearance of high-z quasars could instead be understood more reasonably in the context of the R_h=ct Universe, which does not suffer from the same time compression issues as LCDM does at early epochs. Here, we build on that work by demonstrating that the evolutionary growth of primordial galaxies was consistent with the current view of how the first stars formed, but only with the timeline afforded by the R_h=ct cosmology. We also show that the growth of high-z quasars was mutually consistent with that of the earliest galaxies, though it is not yet clear whether the former grew from 5-20 solar-mass seeds created in Population III or Population II supernova explosions.

Fulvio Melia

2014-03-03T23:59:59.000Z

406

Power-Law NLED-Based Magnetic Universe Can Mimic Phantom Behavior  

E-Print Network (OSTI)

We study the cosmic dynamics of a magnetic universe supported by non-linear electrodynamics (NLED) Lagrangeans that are proportional to powers of the electromagnetic invariant $\\propto F^{1/(1-m)}$ ($m$ is an overall constant). For simplicity we focus in the case when $F$ depends on the magnetic field alone, a case dubbed in the bibliography as ''magnetic universe''. Our results demonstrate that, depending on the values of the free parameter $m$, the magnetic field can mimic phantom field behavior, an effect previously found in other contexts. It is demonstrated that, since there are found equilibrium points in the phase space of these models that can be associated with magnetic-dominated past and future attractors, a combination of positive and negative powers of $F$ may lead to interesting cosmological behavior. In particular, a cosmological scenario where the universe might evolve from a past NLED-driven (non-inflationary) state into a future (late-time) -- also NLED-driven -- inflationary stage, transiting through a matter-dominated solution, is envisioned. The impact of braneworld gravity on the dynamics driven by such NLED Lagrangeans is also investigated. It is demonstrated that, due to phantom property at late times, the non-linear electromagnetic effects may play an important role in deciding the fate of the cosmic evolution. Randall-Sundrum brane effects, in particular, modify the nature of the starting point of the cosmic evolution, as well as the fate of the expansion: both, the big bang singularity and the big rip event -- inherent in general relativity with phantom matter source --, may be avoided.

Ricardo García-Salcedo; Tame Gonzalez; Claudia Moreno; Israel Quiros

2010-06-11T23:59:59.000Z

407

Ultra High Energy Cosmic Rays, Z-Shower and Neutrino Astronomy by Horizontal-Upward Tau Air-Showers  

E-Print Network (OSTI)

Ultra High Cosmic Rays (UHECR) Astronomy may be correlated to a primary parental Neutrino Astronomy: indeed any far BL Lac Jet or GRB, sources of UHECR, located at cosmic edges, may send its signal, overcoming the severe GZK cut-off, by help of UHE ZeV energetic neutrino primary. These UHE neutrino scattering on relic light ones (spread on wide Hot Local Groups Halos) maybe fine-tuned : E_(nu) =(M_Z)^2/m_(nu) = 4 10^(22) eV *((0.1eV)/m_(nu)), to combine at once the observed light neutrino masses and the UHECR spectra, leading to a relativistic Z-Shower in Hot Dark Halos (e few tens Mpc wide) whose final nuclear component traces the UHECR event on Earth. Therefore UHECR (with no longer volme GZK constrains) may point to far BL Lac sources. This Z-Burst (Z-Shower) model calls for large neutrino fluxes. Even if Nature do not follow the present Z-model, UHECR while being cut-off by Big Bang Radiation, must produce a minimal UHE neutrino flux, the GZK neutrino secondaries. For both reasons such UHE Neutrino Astronomy must be tested on Earth. Lowest High Energy Astronomy is searched by AMANDA, ANTARES underground deterctors by muons tracks. We suggest a complementary higher energy Neutrino Tau Astronomy inducing Horizontal and Upward Tau AirShowers. Possible early evidence of such a New Neutrino UPTAUs (Upward Tau Showers at PeVs energies) Astronomy may be in BATSE records of Upward Terrestrial Gamma Flashes. Future signals must be found in detectors as EUSO, seeking Upward-Horizontal events: indeed even minimal, guaranteed, GZK neutrino fluxes may be better observed if EUSO threshold reaches 10^(19) eV by enlarging its telescope size.

D. Fargion

2003-06-24T23:59:59.000Z

408

Grand unified theories and supersymmetry in particle physics and cosmology  

Science Journals Connector (OSTI)

A review is given on the consistency checks of Grand Unified Theories (GUT), which unify the electroweak and strong nuclear forces into a single theory. Such theories predict a new kind of force, which could provide answers to several open questions in cosmology. The possible role of such a “primeval” force will be discussed in the framework of the Big Bang Theory. Although such a force cannot be observed directly, there are several predictions of GUT's, which can be verified at low energies. The Minimal Supersymmetric Standard Model (MSSM) distinguishes itself from other GUT's by a successful prediction of many unrelated phenomena with a minimum number of parameters. Among them: a) Unification of the couplings constants; b) Unification of the masses; c) Existence of dark matter; d) Proton decay; e) Electroweak symmetry breaking at a scale far below the unification scale. A fit of the free parameters in the MSSM to these low energy constraints predicts the masses of the as yet unobserved superpartners of the SM particles, constrains the unknown top mass to a range between 140 and 200 GeV, and requires the second order QCD coupling constant to be between 0.108 and 0.132. “The possibility that the universe was generated from nothing is very interesting and should be further studied. A most perplexing question relating to the singularity is this: what preceded the genesis of the universe? This question appears to be absolutely methaphysical, but our experience with metaphysics tells us that metaphysical questions are sometimes given answers by physics.” A. Linde (1982)

W De Boer

1994-01-01T23:59:59.000Z

409

Submitted to ApJ Letters, June 29, 2005 Are Presolar Silicon Carbide Grains from Novae Actually from Supernovae?  

E-Print Network (OSTI)

Submitted to ApJ Letters, June 29, 2005 Are Presolar Silicon Carbide Grains from Novae Actually stellar nucleosynthesis and mixing. The best-studied presolar phase, silicon carbide (SiC), exhibits

Nittler, Larry R.

410

Microwave cavity searches for dark-matter axions  

Science Journals Connector (OSTI)

Recent determinations of cosmological parameters point to a flat Universe, whose total energy density is composed of about two-thirds vacuum energy and one-third matter. Ordinary baryonic matter is relegated to a small fraction of the latter, within which the luminous part is an order of magnitude smaller yet. Particle dark matter, i.e., one or more relic particle species from the big bang, is thus strongly suggested as the dominant component of matter in the Universe. The axion, a hypothetical elementary pseudoscalar arising from the Peccei-Quinn solution to the strong-CP problem, is a well-motivated candidate. If the axion exists, it must be extremely light, in the mass range of 10-6–10-3 eV, and possess extraordinarily feeble couplings to matter and radiation. Nevertheless, as proposed by Sikivie in 1983, the axion’s two-photon coupling lends itself to a feasible search strategy with currently available technology. In this scheme, axions resonantly convert to single microwave photons by a Primakoff interaction, in a tunable microwave cavity permeated by a strong magnetic field. Present experiments utilizing heterostructure transistor microwave amplifiers have achieved total system noise temperatures of ?3 K and represent the world’s quietest spectral radio receivers. Exclusion regions have already been published well into the band of realistic axion model couplings, within the lowest decade of mass range. Recent breakthroughs in the development of near-quantum-limited superconducting quantum interference device amplifiers should reduce the system noise temperature to ?100 mK or less. Ongoing research into using Rydberg-atom single-quantum detectors as the detector in a microwave cavity experiment could further reduce the effective noise temperature. In parallel with improvements in amplifier technology, promising concepts for higher-frequency cavity resonators are being explored to open up the higher decades in mass range. Definitive experiments to find or exclude the axion may therefore be at hand in the next few years. As the microwave cavity technique measures the total energy of the axion, a positive discovery could well reveal fine structure of the signal due to flows of nonthermalized axions. Manifesting diurnal and sidereal modulation, such detailed features would contain a wealth of information about the history, structure, and dynamics of our Milky Way galaxy.

Richard Bradley; John Clarke; Darin Kinion; Leslie J Rosenberg; Karl van Bibber; Seishi Matsuki; Michael Mück; Pierre Sikivie

2003-06-12T23:59:59.000Z

411

Final Technical Report for "High Energy Physics at The University of Iowa"  

SciTech Connect

Particle Physics explores the very fundamental building blocks of our universe: the nature of forces, of space and time. By exploring very energetic collisions of sub-nuclear particles with sophisticated detectors at the colliding beam accelerators (as well as others), experimental particle physicists have established the current theory known as the Standard Model (SM), one of the several theoretical postulates to explain our everyday world. It explains all phenomena known up to a very small fraction of a second after the Big Bang to a high precision; the Higgs boson, discovered recently, was the last of the particle predicted by the SM. However, many other phenomena, like existence of dark energy, dark matter, absence of anti-matter, the parameters in the SM, neutrino masses etc. are not explained by the SM. So, in order to find out what lies beyond the SM, i.e., what conditions at the earliest fractions of the first second of the universe gave rise to the SM, we constructed the Large Hadron Collider (LHC) at CERN after the Tevatron collider at Fermi National Accelerator Laboratory. Each of these projects helped us push the boundary further with new insights as we explore a yet higher energy regime. The experiments are extremely complex, and as we push the boundaries of our existing knowledge, it also requires pushing the boundaries of our technical knowhow. So, not only do we pursue humankind’s most basic intellectual pursuit of knowledge, we help develop technology that benefits today’s highly technical society. Our trained Ph.D. students become experts at fast computing, manipulation of large data volumes and databases, developing cloud computing, fast electronics, advanced detector developments, and complex interfaces in several of these areas. Many of the Particle physics Ph.D.s build their careers at various technology and computing facilities, even financial institutions use some of their skills of simulation and statistical prowess. Additionally, last but not least, today’s discoveries make for tomorrow’s practical uses of an improved life style, case in point, internet technology, fiber optics, and many such things. At The University of Iowa we are involved in the LHC experiments, ATLAS and CMS, building equipment, with calibration and maintenance, supporting the infrastructure in hardware, software and analysis as well as participating in various aspects of data analyses. Our theory group works on fundamentals of field theories and on exploration of non-accelerator high energy neutrinos and possible dark matter searches.

Mallik, Usha; Meurice, Yannick; Nachtman, Jane; Onel, Yasar; Reno, Mary

2013-07-31T23:59:59.000Z

412

Realistic fission model and the r-process in neutron star mergers  

SciTech Connect

About half of heavy elements are considered to be produced by the rapid neutron-capture process, r-process. The neutron star merger is one of the viable candidates for the astrophysical site of r-process nucleosynthesis. Nuclear fission reactions play an important role in the r-process of neutron star mergers. However theoretical predictions about fission properties of neutron-rich nuclei have some uncertainties. Especially, their fission fragment distributions are totally unknown and the phenomenologically extrapolated distribution was often applied to nucleosynthesis calculations. In this study, we have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions. We discuss the effects on the r-process in neutron star mergers from the nuclear fission of heavy neutron-rich actinide elements. We also discuss how variations in the fission fragment distributions affect the abundance pattern.

Shibagaki, S.; Kajino, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Chiba, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8850 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, IN 46556, U.S.A. and National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2014-05-09T23:59:59.000Z

413

I  

Gasoline and Diesel Fuel Update (EIA)

I 0'^TM^^^^^^^^^^^^^^^^^BBn~fi^H(iA w _ __--^^^^^^^^^^r I A ^^^^^^H^^^^fnffA^ ^^^^^^^^^^5!ii53^^^^^^^^^H~~~~f ^^^^^^^^^^^*^^^^^^^^^^^^^1~~~~A ^^^^^^^^^^^^^j^^^^^^^^^^^^^^^^^ ^^^^^^^^^HB|^B^^BI^^^^^^^^^H ^^^^^^^^^^^^^^^H xe^ ^^^^^^A^ This publication is available from the Superintendent of Documents, U.S. Government Printing Office (GPO). Ordering information and purchase of this and other Energy Information Administration (EIA) publications may be obtained from the GPO or the EIA's National Energy Information Center (NEIC). Questions on energy statistics should be directed to the NEIC. Addresses and telephone numbers appear below. National Energy Information Center, El-20 Energy Information Administration Forrestal Building Room 1 F-048 Washington, D C 20585

414

July 28, 2010, Partnerships of academia, industry, and government labs  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED * Interdisciplinary nature of research * Rapid transition from research to products One size does not fit all Partnerships of academia, industry, and government labs UNCLASSIFIED UNCLASSIFIED Network Science Collaborative Technology Alliance: an Interdisciplinary Collaboration Model Social/Cognitive Network ARC * Principal Member - Rensselaer Polytechnic Institute * General Members - CUNY, Northeastern Univ, IBM Communication Networks ARC * Principal Member - Penn State * General Members - CUNY, USC, UC-Davis, UC-Santa Cruz Information Networks ARC * Principal Member - Univ of Illinois, Urbana Champaign * General Members - CUNY, UC-Santa Barbara, IBM Interdisciplinary Research Center * Principal Member - BBN Tech * General Members - UC-Riverside,

415

Evaluation of 64Cu-Labeled Bifunctional Chelate–Bombesin Conjugates  

Science Journals Connector (OSTI)

DOTA-, NOTA-(1,4,7-triazacyclononane-1,4,7-triacetic acid), PCTA-(3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic ... acid), and Oxo-DO3A-(1-oxa-4,7,10-triazacyclododecane-4,7,10-triacetic acid) peptide conjugates were prepared using H2N-Aoc-[d-Tyr6,?Ala11,Thi13,Nle14]bombesin(6–14) (BBN) as a peptide template. ... Finally, data were analyzed with GraphPad Prism 5 software to determine the IC50 value. ...

Samia Ait-Mohand; Patrick Fournier; Ve?ronique Dumulon-Perreault; Garry E. Kiefer; Paul Jurek; Cara L. Ferreira; Franc?ois Be?nard; Brigitte Gue?rin

2011-07-18T23:59:59.000Z

416

Two-loop QED Operator Matrix Elements with Massive External Fermion Lines  

E-Print Network (OSTI)

The two-loop massive operator matrix elements for the fermionic local twist--2 operators with external massive fermion lines in Quantum Electrodynamics (QED) are calculated up to the constant terms in the dimensional parameter $\\epsilon = D - 4$. We investigate the hypothesis of Ref. \\cite{BBN} that the 2--loop QED initial state corrections to $e^+e^-$ annihilation into a virtual neutral gauge boson, except power corrections of $O((m_f^2/s)^k), k \\geq 1$, can be represented in terms of these matrix elements and the massless 2-loop Wilson coefficients of the Drell-Yan process.

Johannes Blümlein; Abilio De Freitas; Wilhelmus van Neerven

2011-07-22T23:59:59.000Z

417

Error analysis for resonant thermonuclear reaction rates  

Science Journals Connector (OSTI)

A detailed presentation is given of estimating uncertainties in thermonuclear reaction rates for stellar nucleosynthesis involving narrow resonances, starting from random errors in measured or calculated resonance and nuclear level properties. Special attention is given to statistical matters such as probability distributions, error propagation, and correlations between errors. Interpretation of resulting uncertainties in reaction rates and the distinction between symmetric and asymmetric errors are also discussed. Computing reaction rate uncertainties is described. We give examples from explosive nucleosynthesis by hydrogen burning on light nuclei.

William J. Thompson; C. Iliadis

1999-01-01T23:59:59.000Z

418

Coupling highly excited nuclei to the atomic shell in dense astrophysical plasmas  

E-Print Network (OSTI)

In dense astrophysical plasmas, neutron capture populates highly excited nuclear states close to the neutron threshold. The impact of additional low-energy nuclear excitations via coupling to the atomic shell on the ability of the so-formed compound nucleus to retain the captured neutron is investigated. We focus on the mechanism of nuclear excitation by electron capture in plasmas characterized by electron fluxes typical for the slow neutron capture process of stellar nucleosynthesis. The small effect of this further excitation on the neutron capture and gamma decay sequence relevant for nucleosynthesis is quantified and compared to the corresponding effect of an additional low-energy photoexcitation step.

Stephan Helmrich; Katja Spenneberg; Adriana Pálffy

2014-04-25T23:59:59.000Z

419

Coupling highly excited nuclei to the atomic shell in dense astrophysical plasmas  

E-Print Network (OSTI)

In dense astrophysical plasmas, neutron capture populates highly excited nuclear states close to the neutron threshold. The impact of additional low-energy nuclear excitations via coupling to the atomic shell on the ability of the so-formed compound nucleus to retain the captured neutron is investigated. We focus on the mechanism of nuclear excitation by electron capture in plasmas characterized by electron fluxes typical for the slow neutron capture process of stellar nucleosynthesis. The small effect of this further excitation on the neutron capture and gamma decay sequence relevant for nucleosynthesis is quantified and compared to the corresponding effect of an additional low-energy photoexcitation step.

Helmrich, Stephan; Pálffy, Adriana

2014-01-01T23:59:59.000Z

420

Contrasting copper evolution in Omega Centauri and the Milky Way  

E-Print Network (OSTI)

Despite the many studies on stellar nucleosynthesis published so far, the scenario for the production of Cu in stars remains elusive. In particular, it is still debated whether copper originates mostly in massive stars or type Ia supernovae. To answer this question, we compute self-consistent chemical evolution models taking into account the results of updated stellar nucleosynthesis. By contrasting copper evolution in Omega Cen and the Milky Way, we end up with a picture where massive stars are the major responsible for the production of Cu in Omega Cen as well as the Galactic disc.

Donatella Romano; Francesca Matteucci

2007-03-29T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
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421

Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No. 2 January 2003 - March 2003  

SciTech Connect

OAK A271 Hydroacoustic Studies Using HydroCAM - Station-centric Integration of Models and Observations Quarterly Report No. 2 January 2003 - March 2003. BBN's work from January through March of 2003 was focused on data collection, data analysis and software development. We continued our efforts to collect ground truth hydroacoustic data from sub-sea earthquakes in the Indian Ocean. These data are recorded on the International Monitoring System stations at Diego Garcia and Cape Leeuwin. The software development effort spanned two areas. Fixing problems and making small improvements to HydroCAM based on meetings at AFTAC in September 2002. We have also begun development of the software that will integrate local high-resolution bathymetry into lower-resolution global bathymetry for acoustic path predictions in HydroCAM. We hope that this will improve HydroCAM's ability to predict acoustic blockage. Unfortunately, due to corporate travel restrictions stemming from the war with Iraq, BBN will not be able to participate in the International Hydroacoustics Meeting in Hobart, Tasmania in May. However, we plan to provide Phil Harben with material to present and we plan to participate in the annual Seismic Research Review in Arizona this September.

Pulli, Jay J.; Upton, Zachary M.

2003-04-21T23:59:59.000Z

422

Overview of Neutrino-Nucleus Interactions  

Science Journals Connector (OSTI)

......at different energy ranges. Input into Astrophysics: This includes...core-collapse supernovae and also input into the r-process nucleosynthesis...nuclei. (A discus- sion of nuclear fusion cross sections that are important...requires at least three pieces of input: i) A one-body piece that......

A. B. Balantekin

2002-03-01T23:59:59.000Z

423

Measurements of neutron-induced reactions in inverse kinematics  

E-Print Network (OSTI)

Neutron capture cross sections of unstable isotopes are important for neutron induced nucleosynthesis as well as for technological applications. A combination of a radioactive beam facility, an ion storage ring and a high flux reactor would allow a direct measurement of neutron induced reactions over a wide energy range on isotopes with half lives down to minutes.

René Reifarth; Yuri A. Litvinov

2013-12-13T23:59:59.000Z

424

Reionization of the Universe  

Science Journals Connector (OSTI)

......and came earlier from high energy cosmic rays interacting with...understood by known high-energy physics. Most notably, nucleosynthesis...metallicity level of 10-4 in solar units). At this point the...reionization may be relatively economical, because the fraction of mass......

Renyue Cen

2005-02-01T23:59:59.000Z

425

(Experimental physics at Yale University: Research proposal and budget Proposal, 1 January 1992--31 December 1996)  

SciTech Connect

This report reviews the following topics: nuclear and quark matter; correlated pairs from heavy ion collisions-search for new low mass resonances coupled to electron-positron collisions; proposed light ion research program; experimental nuclear astrophysics (explosive nucleosynthesis); search for rare decay modes and rare processes in nuclei; and nuclear spectroscopy at the extremes of spin, isospin, and temperature. (LSP).

Not Available

1992-01-01T23:59:59.000Z

426

[Experimental physics at Yale University: Research proposal and budget Proposal, 1 January 1992--31 December 1996  

SciTech Connect

This report reviews the following topics: nuclear and quark matter; correlated pairs from heavy ion collisions-search for new low mass resonances coupled to electron-positron collisions; proposed light ion research program; experimental nuclear astrophysics (explosive nucleosynthesis); search for rare decay modes and rare processes in nuclei; and nuclear spectroscopy at the extremes of spin, isospin, and temperature. (LSP).

Not Available

1992-07-01T23:59:59.000Z

427

Radiative lifetime measurements of highly excited even-parity levels of Eu I  

Science Journals Connector (OSTI)

......in a laser-produced plasma. This work is the largest-scale...nucleosynthesis and stellar atmospheric processes (Bergstrom...in a laser-induced plasma. 2 EXPERIMENTAL SETUP...flight-out-of-view effect. A 500-MHz digital oscilloscope...recombination background from the plasma (Berzinsh et al. 1997......

Wei Zhang; Shan Du; Yanyan Feng; Liyun Jiang; Zhankui Jiang; Zhenwen Dai

2011-05-21T23:59:59.000Z

428

$^{180}$Ta production in the classical s-process  

E-Print Network (OSTI)

The production and survival of the quasistable isomer $^{180}$Ta during the stellar nucleosynthesis has remained a matter of discussion for years. A careful analysis of the available experimental data and theoretical calculations enabled us to reproduce the observed solar abundance of $^{180}$Ta in the classical s-process ($kT=28$ keV -- 33 keV).

Markus Loewe; Petr Alexa; Jorrit de Boer; Michael Wuerkner

2002-07-04T23:59:59.000Z

429

Thermal properties of light nuclei from 12 fusion-evaporation reactions2  

E-Print Network (OSTI)

applications of nuclear44 physics, from nucleosynthesis calculations to reactor science. Its direct measurement of two, a comparison to a dedicated Hauser-Feshbach calculation allows to24 select a set of dissipative from direct reactions and/or -clustering32 effects. These channels are studied in further details

Paris-Sud XI, Université de

430

Photonuclear reactions in astrophysics  

SciTech Connect

Direct determination of photodisintegration cross sections with quasi-monochromatic {gamma} rays from laser Compton scattering has shed new light on nucleosynthesis. Presented here are results of photoneutron cross-section measurements dedicated to investigating the origin of 180Tam, the only naturally occurring isomer and the rarest isotope in the solar system.

Utsunomiya, H. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan)

2006-11-02T23:59:59.000Z

431

ccsd-00009559,version1-5Oct2005 Astronomy & Astrophysics manuscript no. hal.hyper17418 October 5, 2005 (DOI: will be inserted by hand later)  

E-Print Network (OSTI)

is exposed to a temperature as high as 3.5 Ã? 108 K, which corresponds to an equilibrium den- sity of about the He-burning shell suffers recurrent ther- mal instabilities (thermal pulses or TPs). After each TP 1011 neutrons per cm-3 . However, due to such a high neutron density, the resulting nucleosynthesis

Paris-Sud XI, Université de

432

Direct Measurements of 22 Mg Resonances and Consequences  

E-Print Network (OSTI)

that depend on the thermonuclear rate of the 22Naðp; �23Mg reaction. We have measured the strengths of low A classical nova is a thermonuclear outburst on the surface of a white-dwarf star that is accreting hydrogen nucleosynthesis because most of the relevant thermonuclear reaction rates are based on experimental information [1

Garcia, Alejandro

433

834 NATURE PHYSICS | VOL 7 | NOVEMBER 2011 | www.nature.com/naturephysics news & views  

E-Print Network (OSTI)

-rays of sufficiently high energy to excite photonuclear reactions. Such a source would enable us to study exotic . But it suffers from low efficiency and requires a high-energy electron beam. Another alternative6 involves phenomena, such as the nucleosynthesis of atomic elements in supernovae and photo-induced nuclear fission

Loss, Daniel

434

The Astrophysical Journal, 740:8 (18pp), 2011 October 10 doi:10.1088/0004-637X/740/1/8 C 2011. The American Astronomical Society. All rights reserved. Printed in the U.S.A.  

E-Print Network (OSTI)

. Key words: convection ­ hydrodynamics ­ methods: numerical ­ nuclear reactions, nucleosynthesis transitioning into a detonation. The energy released from the reactions overcomes the gravitational binding hours of this convection using the low Mach number hydrodynamics code, MAESTRO. We present calculations

435

Absolute Time Radiometric Dating: the source of the dates on  

E-Print Network (OSTI)

Absolute Time Radiometric Dating: the source of the dates on the Geologic Time Scale Radiometric.g. uranium to lead. · The parent element is radioactive, the daughter element is stable. · The decay rate nucleosynthesis. Common Radioactive Elements, Parents and Daughters · Carbon-14, C14 Nitrogen-14, N14 · Uranium

Kammer, Thomas

436

B Flavour Tagging with Artificial Neural Networks for the CDF II Experiment  

SciTech Connect

One of the central questions arising from human curiosity has always been what matter is ultimately made of, with the idea of some kind of elementary building-block dating back to the ancient greek philosophers. Scientific activities of multiple generations have contributed to the current best knowledge about this question, the Standard Model of particle physics. According to it, the world around us is composed of a small number of stable elementary particles: Electrons and two different kinds of quarks, called up and down quarks. Quarks are never observed as free particles, but only as bound states of a quark-antiquark pair (mesons) or of three quarks (baryons), summarized as hadrons. Protons and Neutrons, the constituents forming the nuclei of all chemical elements, are baryons made of up and down quarks. The electron and the electron neutrino - a nearly massless particle without electric charge - belong to a group called leptons. These two quarks and two leptons represent the first generation of elementary particles. There are two other generations of particles, which seem to have similar properties as the first generation except for higher masses, so there are six quarks and six leptons altogether. They were around in large amounts shortly after the beginning of the universe, but today they are only produced in high energetic particle collisions. Properties of particles are described by quantum numbers, for example charge or spin. For every type of particle, a corresponding antiparticle exists with the sign of all charges swapped, but similar properties otherwise. The Standard Model is a very successful theory, describing the properties of all known particles and the interactions between them. Many of its aspects have been tested in various experiments at very high precision. Although none of these experimental tests has shown a significant deviation from the corresponding Standard Model prediction, the theory can not be complete yet: Cosmological aspects like gravity, dark matter and dark energy are not described, and open questions remain in the sector of neutrino masses and neutrino oscillations. Also no answer has been given to the question of matter-antimatter asymmetry observed in the contemporary universe. Assuming that the Big Bang created equal amounts of matter and antimatter, there must be effects where nature treats matter and antimatter somehow different. This can happen through a mechanism called CP violation, which has been observed within the Standard Model, but not in the necessary order of magnitude. For all these reasons, the search for New Physics - theories beyond the Standard Model - is one of the main objectives of modern particle physics. In this global effort, flavour physics is the field of transitions between the different types of quarks, called quark flavours, wherein the examination of B meson oscillations and the search for CP violation in B{sub s}{sup 0} meson decays set the stage for the work presented in this thesis.

Schmidt, Andreas; /Karlsruhe U., EKP

2010-01-01T23:59:59.000Z

437

Advanced Accelerator Concepts Final Report  

SciTech Connect

A major focus of research supported by this Grant has been on the ALPHA antihydrogen trap. We first trapped antihydrogen in 2010 and soon thereafter demonstrated trapping for 1000s. We now have observed resonant quantum interactions with antihydrogen. These papers in Nature and Nature Physics report the major milestones in anti-atom trapping. The success was only achieved through careful work that advanced our understanding of collective dynamics in charged particle systems, the development of new cooling and diagnostics, and in- novation in understanding how to make physics measurements with small numbers of anti-atoms. This research included evaporative cooling, autoresonant excitation of longitudinal motion, and centrifugal separation. Antihydrogen trapping by ALPHA is progressing towards the point when a important theories believed by most to hold for all physical systems, such as CPT (Charge-Parity-Time) invariance and the Weak Equivalence Principle (matter and antimatter behaving the same way under the influence of gravity) can be directly tested in a new regime. One motivation for this test is that most accepted theories of the Big Bang predict that we should observe equal amounts of matter and antimatter. However astrophysicists have found very little antimatter in the universe. Our experiment will, if successful over the next seven years, provide a new test of these ideas. Many earlier detailed and beautiful tests have been made, but the trapping of neutral antimatter allows us to explore the possibility of direct, model-independent tests. Successful cooling of the anti atoms, careful limits on systematics and increased trapping rates, all planned for our follow-up experiment (ALPHA-II) will reach unrivaled precision. CPT invariance implies that the spectra of hydrogen and antihydrogen should be identical. Spectra can be measured in principle with great precision, and any di#11;erences we might observe would revolutionize fundamental physics. This is the physics motivation for our experiment, one that requires only a few dozen researchers but must effectively integrate plasma, accelerator, atomic, and fundamental physics, as well as combine numerous technologies in the control, manipulation, and measurement of neutral and non-neutral particles. The ELENA ring (to which we hope to contribute, should funding be provided) is expect, when completed, to significantly enhance the performance of antihydrogen trapping by increasing by a factor of 100 the number of antiprotons that can be successfully trapped and cooled. ELENA operation is scheduled to commence in 2017. In collaboration with LBNL scientists, we proposed a frictional cooling scheme. This is an alternative cooling method to that used by ELENA. It is less complicated, experimentally unproven, and produces a lower yield of cold antiprotons. Students and postdoctoral researchers work on the trapping, cooling, transport, and nonlinear dynamics of antiprotons bunches that are provided by the AD to ALPHA; they contribute to the operation of the experiment, to software development, and to the design and operation of experiments. Students are expected to spend at summers at CERN while taking courses; after completion of courses they typically reside at CERN for most of the half-year run. The Antiproton Decelerator [AD] at CERN, along with its experiments, is the only facility in the world where antiprotons can be trapped and cooled and combined with positrons to form cold antihydrogen, with the ultimate goal of studying CPT violation and, subsequently, gravitational interactions of antimatter. Beyond the ALPHA experiment, the group worked on beam physics problems including limits on the average current in a time-dependent period cathode and new methods to create longitudinally coherent high repetition rate soft x-ray sources and wide bandwidth mode locked x-ray lasers. We completed a detailed study of quantum mechanical effects in the transit time cooling of muons.

Wurtele, Jonathan S.

2014-05-13T23:59:59.000Z

438

An Anticipatory and Deceptive AI Utilizing Bayesian Belief Networks  

SciTech Connect

The U.S. military defines antiterrorism as the defensive posture taken against terrorist threats. Antiterrorism includes fostering awareness of potential threats, deterring aggressors, developing security measures, planning for future events, interdicting an event in progress, and ultimately mitigating and managing the consequences of an event. Recent events highlight the need for efficient tools for training our military and homeland security officers for anticipating threats posed by terrorists. These tools need to be easy enough so that they are readily usable without substantial training, but still maintain the complexity to allow for a level of deceptive reasoning on the part of the opponent. To meet this need, we propose to integrate a Bayesian Belief Network (BBN) model for threat anticipation and deceptive reasoning into training simulation environments currently utilized by several organizations within the Department of Defense (DoD). BBNs have the ability to deal with various types of uncertainties; such as identities, capabilities, target attractiveness, and the combinations of the previous. They also allow for disparate types of data to be fused in a coherent, analytically defensible, and understandable manner. A BBN has been developed by ORNL uses a network engineering process that treats the probability distributions of each node with in the broader context of the system development effort as a whole, and not in isolation. The network will be integrated into the Research Network Inc,(RNI) developed Game Distributed Interactive Simulation (GDIS) as a smart artificial intelligence module. GDIS is utilized by several DoD and civilian organizations as a distributed training tool for a multiplicity of reasons. It has garnered several awards for its realism, ease of use, and popularity. One area that it still has room to excel in, as most video training tools do, is in the area of artificial intelligence of opponent combatants. It is believed that by utilizing BBN as the backbone of the artificial intelligence code, a more realistic and helpful training experience will be available and enemy combatants that move and strategize with purpose will be obtained.

Lake, Joe E [ORNL; Allgood, Glenn O [ORNL; Olama, Mohammed M [ORNL; Saffold, JAy [Research Network, Inc

2009-01-01T23:59:59.000Z

439

Fermilab Today  

NLE Websites -- All DOE Office Websites (Extended Search)

, 2006 , 2006 Calendar Monday, May 1 11:00 a.m. Academic Lecture Series - Curia II Speaker: S. Dodelson, Fermilab Title: The Clumpy Universe - Course 6b (3rd Lecture) 2:30 p.m. Particle Astrophysics Seminar - Curia II Speaker: G. Steigman, Ohio State University Title: Schrammfest: BBN: Successes and Challenges 3:30 p.m. DIRECTOR'S COFFEE BREAK - 2nd Flr X-Over 4:00 p.m. All Experimenters' Meeting - Curia II Special Topics: Recent Activity at the Test Beam; NuMI Horn Repair Tuesday, May 2 12:30 p.m. Lunchtime Video Presentation - Curia II Chernobyl: A BBC Dramatization 2:00 p.m. Research Techniques Seminar - West Wing (WH-10NW) Speaker: G. Deptuch, Brookhaven National Laboratory Title: Monolithic Active Pixel Sensors for Not Visible Light Applications: Advantages and Limitations

440

Cosmological and astrophysical constraints on superconducting cosmic strings  

SciTech Connect

We investigate the cosmological and astrophysical constraints on superconducting cosmic strings (SCSs). SCS loops emit strong bursts of electromagnetic waves, which might affect various cosmological and astrophysical observations. We take into account the effect on the CMB anisotropy, CMB blackbody spectrum, BBN, observational implications on radio wave burst and X-ray or ?-ray events, and stochastic gravitational wave background measured by pulsar timing experiments. We then derive constraints on the parameters of SCS from current observations and estimate prospects for detecting SCS signatures in on-going observations. As a result, we find that these constraints exclude broad parameter regions, and also that on-going radio wave observations can probe large parameter space.

Miyamoto, Koichi [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Nakayama, Kazunori, E-mail: miyamone@icrr.u-tokyo.ac.jp, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2013-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Progress in the physics of massive neutrinos  

E-Print Network (OSTI)

The current status of the physics of massive neutrinos is reviewed with a forward-looking emphasis. The article begins with the general phenomenology of neutrino oscillations in vacuum and matter and documents the experimental evidence for oscillations of solar, reactor, atmospheric and accelerator neutrinos. Both active and sterile oscillation possibilities are considered. The impact of cosmology (BBN, CMB, leptogenesis) and astrophysics (supernovae, highest energy cosmic rays) on neutrino observables and vice versa, is evaluated. The predictions of grand unified, radiative and other models of neutrino mass are discussed. Ways of determining the unknown parameters of three-neutrino oscillations are assessed, taking into account eight-fold degeneracies in parameters that yield the same oscillation probabilities, as well as ways to determine the absolute neutrino mass scale (from beta-decay, neutrinoless double-beta decay, large scale structure and Z-bursts). Critical unknowns at present are the amplitude of \

V. Barger; D. Marfatia; K. Whisnant

2003-09-16T23:59:59.000Z

442

Abstract for Carla Froehlich  

NLE Websites -- All DOE Office Websites (Extended Search)

Carla Froehlich Carla Froehlich University of Basel, Switzerland Core Collapse Supernovae: New Aspects of Nucleosynthesis and their Imprint on Galactic Evolution In 1D, a self-consistent treatment of core collapse supernovae with presently known input physics and computer simulations does not yet lead to successful explosions, while 2D models show promise. On the other hand there is a need to provide correct nucleosynthesis abundances for the quickly evolving field of galactic evolution and observations of low metallicity stars. The innermost ejecta are directly affected by the explosion mechanism, most strongly the yields of Fe-group nuclei for which an induced piston or thermal bomb treatment will not provide the correct yields because the neutrino interactions are not included. I will show how

443

The Universe Adventure - Galaxial Motion  

NLE Websites -- All DOE Office Websites (Extended Search)

Bulk Motions of Galaxies Bulk Motions of Galaxies Galaxy Diagram The Structure of a typical Spiral Galaxy. Galaxies are most often found in clusters and are thus subject to gravitational forces from their neighbors. The relative motion that results from these interactions causes deviations from the cosmological principle called bulk flow. Measuring the peculiar velocities enables cosmologists to calculate the masses of interacting galaxies. Using this technique scientists can estimate the total density of matter in the Universe. During the recombination epoch, the Universe had cooled sufficiently for nucleosynthesis to occur. However, this process produces only a few elements, and looking at the abundance of these elements today is indicative of the rate of nucleosynthesis and the amount of baryonic mass

444

Abstract for Khalil Farouqi  

NLE Websites -- All DOE Office Websites (Extended Search)

Farouqi Farouqi University of Chicago and Argonne Explosive nucleosynthesis in the high-entropy wind of core-collapse supernovae In an attempt to constrain the astrophysical conditions for the nucleosynthesis of the classical r-process elements beyond Fe, we have performed large-scale dynamical network calculations within the model of an adiabatically expanding high-entropy wind (HEW) of type II supernovae (SN II). A superposition of several entropy-components (S) with model-inherent weighting results in an excellent reproduction of the overall Solar System (SS) isotopic r-process residuals, as well as the more recent observations of elemental abundances of metal-poor, r-process-rich halo-stars in the early Galaxy. For the heavy r-process elements beyond Sn, our HEW model

445

Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances  

SciTech Connect

Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

Thompson, I J [Lawrence Livermore National Laboratory (LLNL)] [Lawrence Livermore National Laboratory (LLNL); Escher, Jutta E [ORNL] [ORNL; Arbanas, Goran [ORNL] [ORNL

2013-01-01T23:59:59.000Z

446

Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances  

Science Journals Connector (OSTI)

Abstract Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5–20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,?)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,?)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.

I.J. Thompson; J.E. Escher; G. Arbanas

2014-01-01T23:59:59.000Z

447

Theoretical models for Type I and Type II supernova  

SciTech Connect

Recent theoretical progress in understanding the origin and nature of Type I and Type II supernovae is discussed. New Type II presupernova models characterized by a variety of iron core masses at the time of collapse are presented and the sensitivity to the reaction rate /sup 12/C(..cap alpha..,..gamma..)/sup 16/O explained. Stars heavier than about 20 M/sub solar/ must explode by a ''delayed'' mechanism not directly related to the hydrodynamical core bounce and a subset is likely to leave black hole remnants. The isotopic nucleosynthesis expected from these massive stellar explosions is in striking agreement with the sun. Type I supernovae result when an accreting white dwarf undergoes a thermonuclear explosion. The critical role of the velocity of the deflagration front in determining the light curve, spectrum, and, especially, isotopic nucleosynthesis in these models is explored. 76 refs., 8 figs.

Woosley, S.E.; Weaver, T.A.

1985-01-01T23:59:59.000Z

448

Neutrino-driven wind and wind termination shock in supernova cores  

E-Print Network (OSTI)

The neutrino-driven wind from a nascent neutron star at the center of a supernova expands into the earlier ejecta of the explosion. Upon collision with this slower matter the wind material is decelerated in a wind termination shock. By means of hydrodynamic simulations in spherical symmetry we demonstrate that this can lead to a large increase of the wind entropy, density, and temperature, and to a strong deceleration of the wind expansion. The consequences of this phenomenon for the possible r-process nucleosynthesis in the late wind still need to be explored in detail. Two-dimensional models show that the wind-ejecta collision is highly anisotropic and could lead to a directional dependence of the nucleosynthesis even if the neutrino-driven wind itself is spherically symmetric.

A. Arcones; L. Scheck; H. -Th. Janka

2006-12-21T23:59:59.000Z

449

The Role of Fission in Neutron Star Mergers and the Position of the Third r-Process Peak  

E-Print Network (OSTI)

The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model (FRDM), the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral (ETFSI-Q), and the Hartee-Fock-Bogoliubov (HFB) mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which have been noticed in a number of merger ...

Eichler, Marius; Kelic, Alexandra; Korobkin, Oleg; Langanke, Karlheinz; Martinez-Pinedo, Gabriel; Panov, Igor V; Rauscher, Thomas; Rosswog, Stephan; Winteler, Christian; Zinner, Nikolaj T; Thielemann, Friedrich-Karl

2014-01-01T23:59:59.000Z

450

Possible discovery of the r-process characteristics in the abundances of metal-rich barium stars  

E-Print Network (OSTI)

We study the abundance distributions of a sample of metal-rich barium stars provided by Pereira et al. (2011) to investigate the s- and r-process nucleosynthesis in the metal-rich environment. We compared the theoretical results predicted by a parametric model with the observed abundances of the metal-rich barium stars. We found that six barium stars have a significant r-process characteristic, and we divided the barium stars into two groups: the r-rich barium stars ($C_r>5.0$, [La/Nd]\\,$pollution, although their abundance patterns can be fitted very well when the pre-enrichment hypothesis is included. The fact that we can not explain them well using the s-process nucleosynthesis alone may be due to our incomplete knowledge on the production of Nd, Eu, and other relevant elements by the ...

Cui, W Y; Shi, J R; Zhao, G; Wang, W J; Niu, P

2014-01-01T23:59:59.000Z

451

The impact of global nuclear mass model uncertainties on $r$-process abundance predictions  

E-Print Network (OSTI)

Rapid neutron capture or `$r$-process' nucleosynthesis may be responsible for half the production of heavy elements above iron on the periodic table. Masses are one of the most important nuclear physics ingredients that go into calculations of $r$-process nucleosynthesis as they enter into the calculations of reaction rates, decay rates, branching ratios and Q-values. We explore the impact of uncertainties in three nuclear mass models on $r$-process abundances by performing global monte carlo simulations. We show that root-mean-square (rms) errors of current mass models are large so that current $r$-process predictions are insufficient in predicting features found in solar residuals and in $r$-process enhanced metal poor stars. We conclude that the reduction of global rms errors below $100$ keV will allow for more robust $r$-process predictions.

Mumpower, M; Aprahamian, A

2014-01-01T23:59:59.000Z

452

Stars as thermonuclear reactors: their fuels and ashes  

E-Print Network (OSTI)

Atomic nuclei are transformed into each other in the cosmos by nuclear reactions inside stars: -- the process of nucleosynthesis. The basic concepts of determining nuclear reaction rates inside stars and how they manage to burn their fuel so slowly most of the time are discussed. Thermonuclear reactions involving protons in the hydrostatic burning of hydrogen in stars are discussed first. This is followed by triple alpha reactions in the helium burning stage and the issues of survival of carbon and oxygen in red giant stars connected with nuclear structure of oxygen and neon. Advanced stages of nuclear burning in quiescent reactions involving carbon, neon, oxygen and silicon are discussed. The role of neutron induced reactions in nucleosynthesis beyond iron is discussed briefly, as also the experimental detection of neutrinos from SN 1987A which confirmed broadly the ideas concerning gravitational collapse leading to a supernova.

A. Ray

2004-05-28T23:59:59.000Z

453

Neutron beta-decay, Standard Model and cosmology  

E-Print Network (OSTI)

The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. The neutron lifetime recently obtained, 878.5 +/- 0.7stat +/- 0.3sys s, is the most accurate one to date. The new result for the neutron lifetime differs from the world average value by 6.5 standard deviations. The impact of the new result on testing of Standard Model and on data analysis for the primordial nucleosynthesis model is scrutinized.

A. P. Serebrov

2006-11-22T23:59:59.000Z

454

Graviton emission from a Gauss-Bonnet brane  

E-Print Network (OSTI)

We study the emission of gravitons by a homogeneous brane with the Gauss-Bonnet term into an Anti de Sitter five dimensional bulk spacetime. It is found that the graviton emission depends on the curvature scale and the Gauss-Bonnnet coupling and that the amount of emission generally decreases. Therefore nucleosynthesis constraints are easier to satisfy by including the Gauss-Bonnet term.

Kenichiro Konya

2007-05-07T23:59:59.000Z

455

Total cross sections and thermonuclear reaction rates for C13(d,n) and C14(d,n)  

Science Journals Connector (OSTI)

The C13(d,n) and C14(d,n) cross sections have been measured for 0.2?Ec.m.?2.1 MeV and 0.2?Ec.m.?1.3 MeV, respectively, using a 4? neutron detector. The cross sections are used to calculate the thermonuclear reaction rates for temperatures below 10 GK. The implications of these and other new nuclear-physics results for inhomogeneous primordial nucleosynthesis are discussed.

C. R. Brune and R. W. Kavanagh

1992-03-01T23:59:59.000Z

456

Installation of a magnetic spectrometer on the  

E-Print Network (OSTI)

. HEDP facilities ­ The National Ignition Facility (NIF) ­ OMEGA laser 3. Known nuclear reactions used-36 cm-2 s-1) NIF OMEGA p p p d 3He p p p d 3He 4He p p 6Be ve e+ ve e+ g g Nucleosynthesis of light facilities ­ The National Ignition Facility (NIF) ­ OMEGA laser 3. Known nuclear reactions used to probe HEDP

457

The universe in the laboratory - Nuclear astrophysics opportunity at the facility for antiproton and ion research  

SciTech Connect

In the next years the Facility for Antiproton and Ion Research FAIR will be constructed at the GSI Helmholtzze-ntrum für Schwerionenforschung in Darmstadt, Germany. This new accelerator complex will allow for unprecedented and pathbreaking research in hadronic, nuclear, and atomic physics as well as in applied sciences. This manuscript will discuss some of these research opportunities, with a focus on supernova dynamics and nucleosynthesis.

Langanke, K. [GSI Helmholtzzentrum für Schwerionenforschung, Technische Universität Darmstadt, Frankfurt Institute of Advanced Studies, D-64291 Darmstadt (Germany)

2014-05-09T23:59:59.000Z

458

Thermonuclear Runaways on Accreting White Dwarfs: Models of Classical Novae Explosions  

E-Print Network (OSTI)

The mechanism of classical novae explosions is explained, together with some of their observational properties. The scarce but not null impact of novae in the chemical evolution of the Milky Way is analyzed, as well as their relevance for the radioactivity in the Galaxy. A special emphasis is given to the predicted gamma-ray emission from novae and its relationship with the thermonuclear model itself and its related nucleosynthesis.

Margarita Hernanz; Jordi Jose

2000-01-11T23:59:59.000Z

459

Direct measurement of the breakout reaction {sup 11}C({alpha},p){sup 14}N in explosive hydrogen-burning process  

SciTech Connect

We determined the {sup 11}C({alpha},p){sup 14}N reaction rate relevant to the nucleosynthesis in explosive hydrogen-burning stars. The measurement was performed by means of the thick target method in inverse kinematics with {sup 11}C RI beams. We derived the excitation functions for the ground-state transition and excited-state transitions using time-of-flight information for the first time. The present reaction rate is compared to the previous one.

Hayakawa, S.; Kubono, S.; Kahl, D.; Yamaguchi, H.; Binh, Dam N.; Hashimoto, T.; Wakabayashi, Y.; He, J. J.; Iwasa, N.; Kato, S.; Komatsubara, T.; Kwon, Y. K.; Teranishi, T.; Wanajo, S. [Center for Nuclear Study, Graduate of Science, University of Tokyo (Japan) and Institute of Physics (Japan); RCNP, Osaka University (Japan); Japan Atomic Energy Agency (Japan); Institute of Modern Physics (Japan); Department of Physics, Tohoku University (Japan); Department of Physics, Yamagata University (Japan); Department of Physics, University of Tsukuba (Japan); Department of Physics, Chung Ang University (Korea, Republic of); Department of Physics, Kyushu University (Japan); Institute for the Physics and Mathematics of the Universe, University of Tokyo (Japan)

2012-11-12T23:59:59.000Z

460

Moduli Decays and Gravitinos  

SciTech Connect

One proposed solution of the moduli problem of string cosmology requires that the moduli are quite heavy, their decays reheating the universe to temperatures above the scale of nucleosynthesis. In many of these scenarios, the moduli are approximately supersymmetric; it is then crucial that the decays to gravitinos are helicity suppressed. In this paper, we discuss situations where these decays are, and are not, suppressed. We also comment on a possible gravitino problem from inaton decay.

Dine, Michael; Kitano, Ryuichiro; Morisse, Alexander; Shirman, Yuri

2006-04-21T23:59:59.000Z

Note: This page contains sample records for the topic "big-bang nucleosynthesis bbn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

The Role of Fission in Neutron Star Mergers and the Position of the Third r-Process Peak  

E-Print Network (OSTI)

The comparison between observational abundance features and those obtained from nucleosynthesis predictions of stellar evolution and/or explosion simulations can scrutinize two aspects: (a) the conditions in the astrophysical production site and (b) the quality of the nuclear physics input utilized. Here we test the abundance features of r-process nucleosynthesis calculations for the dynamical ejecta of neutron star merger simulations based on three different nuclear mass models: The Finite Range Droplet Model (FRDM), the (quenched version of the) Extended Thomas Fermi Model with Strutinsky Integral (ETFSI-Q), and the Hartee-Fock-Bogoliubov (HFB) mass model. We make use of corresponding fission barrier heights and compare the impact of four different fission fragment distribution models on the final r-process abundance distribution. Furthermore, we explore the origin of a shift in the third r-process peak position in comparison with the solar r-process abundances which have been noticed in a number of merger nucleosynthesis predictions. We show that this shift occurs during the r-process freeze-out when neutron captures and beta-decays compete and an (n,g)-(g,n) equilibrium is not maintained anymore. During this phase neutrons originate mainly from fission of material above A = 240. We also demonstrate that a faster (and thus earlier) release of these neutrons, e.g., by shorter beta-decay half-lives of nuclei with Z > 80, as suggested by recent theoretical advances, can partially prevent this shift.

Marius Eichler; Almudena Arcones; Alexandra Kelic; Oleg Korobkin; Karlheinz Langanke; Gabriel Martinez-Pinedo; Igor V. Panov; Thomas Rauscher; Stephan Rosswog; Christian Winteler; Nikolaj T. Zinner; Friedrich-Karl Thielemann

2014-11-04T23:59:59.000Z

462

REPRODUCING THE OBSERVED ABUNDANCES IN RCB AND HdC STARS WITH POST-DOUBLE-DEGENERATE MERGER MODELS-CONSTRAINTS ON MERGER AND POST-MERGER SIMULATIONS AND PHYSICS PROCESSES  

SciTech Connect

The R Coronae Borealis (RCB) stars are hydrogen-deficient, variable stars that are most likely the result of He-CO WD mergers. They display extremely low oxygen isotopic ratios, {sup 16}O/{sup 18}O {approx_equal} 1-10, {sup 12}C/{sup 13}C {>=} 100, and enhancements up to 2.6 dex in F and in s-process elements from Zn to La, compared to solar. These abundances provide stringent constraints on the physical processes during and after the double-degenerate merger. As shown previously, O-isotopic ratios observed in RCB stars cannot result from the dynamic double-degenerate merger phase, and we now investigate the role of the long-term one-dimensional spherical post-merger evolution and nucleosynthesis based on realistic hydrodynamic merger progenitor models. We adopt a model for extra envelope mixing to represent processes driven by rotation originating in the dynamical merger. Comprehensive nucleosynthesis post-processing simulations for these stellar evolution models reproduce, for the first time, the full range of the observed abundances for almost all the elements measured in RCB stars: {sup 16}O/{sup 18}O ratios between 9 and 15, C-isotopic ratios above 100, and {approx}1.4-2.35 dex F enhancements, along with enrichments in s-process elements. The nucleosynthesis processes in our models constrain the length and temperature in the dynamic merger shell-of-fire feature as well as the envelope mixing in the post-merger phase. s-process elements originate either in the shell-of-fire merger feature or during the post-merger evolution, but the contribution from the asymptotic giant branch progenitors is negligible. The post-merger envelope mixing must eventually cease {approx}10{sup 6} yr after the dynamic merger phase before the star enters the RCB phase.

Menon, Athira; Herwig, Falk; Denissenkov, Pavel A. [Department of Physics and Astronomy, University of Victoria, Victoria, BC V8P5C2 (Canada); Clayton, Geoffrey C.; Staff, Jan [Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Tower Dr., Baton Rouge, LA 70803-4001 (United States); Pignatari, Marco [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Paxton, Bill [Kavli Institute for Theoretical Physics and Department of Physics, Kohn Hall, University of California, Santa Barbara, CA 93106 (United States)

2013-07-20T23:59:59.000Z

463

High-accuracy mass measurements of neutron-rich Kr isotopes  

Science Journals Connector (OSTI)

The atomic masses of the neutron-rich krypton isotopes Kr84,86-95 have been determined with the tandem Penning trap mass spectrometer ISOLTRAP with uncertainties ranging from 20 to 220 ppb. The masses of the short-lived isotopes Kr94 and Kr95 were measured for the first time. The masses of the radioactive nuclides Kr89 and Kr91 disagree by 4 and 6 standard deviations, respectively, from the present Atomic-Mass Evaluation database. The resulting modification of the mass surface with respect to the two-neutron separation energies as well as implications for mass models and stellar nucleosynthesis are discussed.

P. Delahaye; G. Audi; K. Blaum; F. Carrel; S. George; F. Herfurth; A. Herlert; A. Kellerbauer; H.-J. Kluge; D. Lunney; L. Schweikhard; C. Yazidjian

2006-09-28T23:59:59.000Z

464

Nuclear Masses in Astrophysics  

E-Print Network (OSTI)

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

465

Post-Newtonian parameters and constraints on Einstein-aether theory  

Science Journals Connector (OSTI)

We analyze the observational and theoretical constraints on “Einstein-aether theory,” a generally covariant theory of gravity coupled to a dynamical, unit, timelike vector field that breaks local Lorentz symmetry. The results of a computation of the remaining post-Newtonian parameters are reported. These are combined with other results to determine the joint post-Newtonian, vacuum-?erenkov, nucleosynthesis, stability, and positive-energy constraints. All of these constraints are satisfied by parameters in a large two-dimensional region in the four-dimensional parameter space defining the theory.

Brendan Z. Foster and Ted Jacobson

2006-03-15T23:59:59.000Z

466

Chemical Abundances in High-Redshift Neutral Clouds  

E-Print Network (OSTI)

Neutral hydrogen clouds with high column density detected towards distant quasars are unique probes of elemental nucleosynthesis and chemical evolution in the low metallicity regime. They provide measurements for several elements at very early times which are unfeasible in other astrophysical environments. Comparison between refractory and non-refractory elements provides evidence for the presence of dust, and the recently measured Ar probes photoionization. A prominent characteristic is the dominance of a solar abundance pattern, which is somewhat unexpected at low metallicities. It is argued that this property and Nitrogen observations can be used to constrain the age of the Damped Ly_alpha systems and the epoch of star formation.

Paolo Molaro

2001-11-30T23:59:59.000Z

467

On the solar abundance of indium  

E-Print Network (OSTI)

The generally adopted value for the solar abundance of indium is over six times higher than the meteoritic value. We address this discrepancy through numerical synthesis of the 451.13 nm line on which all indium abundance studies are based, both for the quiet-sun and the sunspot umbra spectrum, employing standard atmosphere models and accounting for hyperfine structure and Zeeman splitting in detail. The results, as well as a re-appraisal of indium nucleosynthesis, suggest that the solar indium abundance is close to the meteoritic value, and that some unidentified ion line causes the 451.13 nm feature in the quiet-sun spectrum.

N. Vitas; I. Vince; M. Lugaro; O. Andriyenko; M. Gosic; R. J. Rutten