National Library of Energy BETA

Sample records for oxford big-bang nucleosynthesis

  1. Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Keith A. Olive

    1997-12-11

    The concordance of standard big bang nucleosynthesis theory and the related observations of the light element isotopes (including some new higher \\he4 abundances) will be reviewed. Implications of BBN on chemical evolution, dark matter and constraints on particle properties will be discussed.

  2. Big Bang Nucleosynthesis: 2015

    E-Print Network [OSTI]

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

    2015-01-01

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

  3. Neutrinos and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    A. D. Dolgov

    2002-03-18

    The role of neutrinos in big bang nucleosynthesis is discussed. The bounds on the number of neutrino families, neutrino degeneracy, parameters of neutrino oscillations are presented. A model of chemically inhomogeneous, while energetically smooth, universe created by inhomogeneous cosmological neutrino asymmetry is described. Nucleosynthesis limits on production of right-handed neutrinos are considered.

  4. Big bang nucleosynthesis: An update

    SciTech Connect (OSTI)

    Olive, Keith A. [William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)] [William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2013-07-23

    An update on the standard model of big bang nucleosynthesis (BBN) is presented. With the value of the baryon-tophoton ratio determined to high precision by WMAP, standard BBN is a parameter-free theory. In this context, the theoretical prediction for the abundances of D, {sup 4}He, and {sup 7}Li is discussed and compared to their observational determination. While concordance for D and {sup 4}He is satisfactory, the prediction for {sup 7}Li exceeds the observational determination by a factor of about four. Possible solutions to this problem are discussed.

  5. Quark mass variation constraints from Big Bang nucleosynthesis...

    Office of Scientific and Technical Information (OSTI)

    Quark mass variation constraints from Big Bang nucleosynthesis Citation Details In-Document Search Title: Quark mass variation constraints from Big Bang nucleosynthesis We study...

  6. IMPLICATIONS OF NON-MAXWELLIAN DISTRIBUTIONS ON BIG BANG NUCLEOSYNTHESIS

    E-Print Network [OSTI]

    Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

    #12;IMPLICATIONS OF NON-MAXWELLIAN DISTRIBUTIONS ON BIG BANG NUCLEOSYNTHESIS A Thesis by JOHN FUQUA ON BIG BANG NUCLEOSYNTHESIS A Thesis by JOHN FUQUA Approved by: Advisor: Carlos Bertulani Committee-MAXWELLIAN DISTRIBUTIONS ON BIG BANG NUCLEOSYNTHESIS John Fuqua, MS Texas A&M University-Commerce, 2013 Advisor: Carlos

  7. Dark Radiation Emerging After Big Bang Nucleosynthesis?

    E-Print Network [OSTI]

    Willy Fischler; Joel Meyers

    2011-02-28

    We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could be produced from the decay of non-relativistic matter, we place constraints on the properties of such matter, and we give specific examples of scenarios in which this general scheme may be realized.

  8. Dark radiation emerging after big bang nucleosynthesis?

    SciTech Connect (OSTI)

    Fischler, Willy; Meyers, Joel [Theory Group, Department of Physics, University of Texas, Austin, Texas 78712 (United States) and Texas Cosmology Center, University of Texas, Austin, Texas 78712 (United States)

    2011-03-15

    We show how recent data from observations of the cosmic microwave background may suggest the presence of additional radiation density which appeared after big bang nucleosynthesis. We propose a general scheme by which this radiation could be produced from the decay of nonrelativistic matter, we place constraints on the properties of such matter, and we give specific examples of scenarios in which this general scheme may be realized.

  9. Big Bang Nucleosynthesis and Primordial Black Holes

    E-Print Network [OSTI]

    C. Sivaram; Kenath Arun

    2010-06-28

    There are ongoing efforts in detecting Hawking radiation from primordial black holes (PBH) formed during the early universe. Here we put an upper limit on the PBH number density that could have been formed prior to the big bang nucleosynthesis era, based on the constraint that the PBH evaporation energy consisting of high energy radiation not affect the observed abundances' of elements, by disintegrating the nuclei.

  10. New Nuclear Physics for Big Bang Nucleosynthesis

    E-Print Network [OSTI]

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

    2010-08-04

    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.

  11. LiBeB and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Keith A. Olive; Brian D. Fields

    1999-02-20

    The dual origin of population II Li7, in both big bang nucleosynthesis and galactic cosmic-ray nucleosynthesis is discussed. It is argued that with additional Li6 data, stringent limits on the degree of Li7 depletion can be obtained. Li7 depletion is also constrained by the concordance of big bang predictions with observational determinations of light element abundances. Stringent limits can also be obtained for a fixed primordial D/H abundance.

  12. Dirac Fields in Loop Quantum Gravity and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Martin Bojowald; Rupam Das; Robert J. Scherrer

    2008-03-19

    Big Bang nucleosynthesis requires a fine balance between equations of state for photons and relativistic fermions. Several corrections to equation of state parameters arise from classical and quantum physics, which are derived here from a canonical perspective. In particular, loop quantum gravity allows one to compute quantum gravity corrections for Maxwell and Dirac fields. Although the classical actions are very different, quantum corrections to the equation of state are remarkably similar. To lowest order, these corrections take the form of an overall expansion-dependent multiplicative factor in the total density. We use these results, along with the predictions of Big Bang nucleosynthesis, to place bounds on these corrections.

  13. PHYSICAL REVIEW C 83, 018801 (2011) Electron screening and its effects on big-bang nucleosynthesis

    E-Print Network [OSTI]

    Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

    2011-01-01

    PHYSICAL REVIEW C 83, 018801 (2011) Electron screening and its effects on big-bang nucleosynthesis screening on nuclear reaction rates occurring during the big-bang nucleosynthesis epoch. The sensitivity. This work rules out electron screening as a relevant ingredient to big-bang nucleosynthesis, confirming

  14. Constraints on massive gravity theory from big bang nucleosynthesis

    E-Print Network [OSTI]

    G. Lambiase

    2012-08-27

    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also discussed in the framework of the PAMELA experiment.

  15. Long Lived Charged Massive Particles and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Kazunori Kohri; Fumihiro Takayama

    2006-11-06

    We consider Big Bang Nucleosynthesis(BBN) with long lived charged massive particles. Before decaying, the long lived massive particles recombines with a light element to form a bound state like a hydrogen atom. We discuss the possible change of primordial light element abundances due to formations of such bound states.

  16. Neutrino energy transport in weak decoupling and big bang nucleosynthesis

    E-Print Network [OSTI]

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

    2015-01-01

    We calculate the evolution of the early universe through the epochs of weak decoupling, weak freeze-out and big bang nucleosynthesis (BBN) by simultaneously coupling a full strong, electromagnetic, and weak nuclear reaction network with a multi-energy group Boltzmann neutrino energy transport scheme. Such an approach allows a detailed accounting of the evolution of the $\

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

    E-Print Network [OSTI]

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

    2014-08-15

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

  18. Electron screening and its effects on big-bang nucleosynthesis

    SciTech Connect (OSTI)

    Wang Biao; Bertulani, C. A.; Balantekin, A. B. [Department of Physics, Texas A and M University, Commerce, Texas 75429 (United States); Physics Department, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2011-01-15

    We study the effects of electron screening on nuclear reaction rates occurring during the big-bang nucleosynthesis epoch. The sensitivity of the predicted elemental abundances on electron screening is studied in detail. It is shown that electron screening does not produce noticeable results in the abundances unless the traditional Debye-Hueckel model for the treatment of electron screening in stellar environments is enhanced by several orders of magnitude. This work rules out electron screening as a relevant ingredient to big-bang nucleosynthesis, confirming a previous study [see Itoh et al., Astrophys. J. 488, 507 (1997)] and ruling out exotic possibilities for the treatment of screening beyond the mean-field theoretical approach.

  19. Possible evidence for "dark radiation" from Big Bang Nucleosynthesis Data

    E-Print Network [OSTI]

    V. V. Flambaum; E. V. Shuryak

    2006-02-06

    We address the emerging discrepancy between the Big Bang Nucleosynthesis data and standard cosmology, which asks for a bit longer evolution time. If this effect is real, one possible implication (in a framework of brane cosmology model) is that there is a ``dark radiation'' component which is negative and makes few percents of ordinary matter density. If so, all scales of this model can be fixed, provided brane-to-bulk leakage problem is solved.

  20. Constraints on massive gravity theory from big bang nucleosynthesis

    SciTech Connect (OSTI)

    Lambiase, G., E-mail: lambiase@sa.infn.it [Dipartimento di Fisica 'E. R.Caianiello', Università di Salerno, 84081 Baronissi (Italy)

    2012-10-01

    The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The cosmological consequences of the model are also analyzed in the framework of the PAMELA experiment, i.e. an excess of positron events, that the conventional cosmology and particle physics cannot explain.

  1. BIG BANG NUCLEOSYNTHESIS WITH A NON-MAXWELLIAN DISTRIBUTION

    SciTech Connect (OSTI)

    Bertulani, C. A. [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)] [GSI Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Fuqua, J. [Texas A and M University-Commerce, Commerce, TX 75429-3011 (United States)] [Texas A and M University-Commerce, Commerce, TX 75429-3011 (United States); Hussein, M. S. [Instituto de Estudos Avancados, Universidade de Sao Paulo, C.P. 72.012, 05508-970 Sao Paulo (Brazil)] [Instituto de Estudos Avancados, Universidade de Sao Paulo, C.P. 72.012, 05508-970 Sao Paulo (Brazil)

    2013-04-10

    The abundances of light elements based on the big bang nucleosynthesis model are calculated using the Tsallis non-extensive statistics. The impact of the variation of the non-extensive parameter q from the unity value is compared to observations and to the abundance yields from the standard big bang model. We find large differences between the reaction rates and the abundance of light elements calculated with the extensive and the non-extensive statistics. We found that the observations are consistent with a non-extensive parameter q = 1{sub -} {sub 0.12}{sup +0.05}, indicating that a large deviation from the Boltzmann-Gibbs statistics (q = 1) is highly unlikely.

  2. Neutrinos and Big-Bang Nucleosynthesis

    E-Print Network [OSTI]

    T. KAJINO; M. ORITO

    1998-04-17

    Observations of clusters and super clusters of galaxies have indicated that the Universe is more dominated by baryons than ever estimated in the homogeneous cosmological model for primordial nucleosynthesis. Recent detections of possibly low deuterium abundance in Lyman-$\\alpha$ clouds along the line of sight to high red-shift quasars have raised another potential difficulty that \\he4 is overproduced in any cosmological models which satisfy the low deuterium abundance constraint. We show that the inhomogeneous cosmological model with degenerate electron-neutrino can resolve these two difficulties.

  3. Constraints on Light Dark Matter from Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Brian Henning; Hitoshi Murayama

    2012-05-29

    We examine the effects of relic dark matter annihilations on big bang nucleosynthesis (BBN). The magnitude of these effects have scale simply with the dark matter mass and annihilation cross-section, which we derive. Estimates based on these scaling behaviors indicate that BBN severely constrains hadronic and radiative dark matter annihilation channels in the previously unconsidered dark matter mass region MeV $\\lesssim m_{\\chi} \\lesssim 10$ GeV. Interestingly, we find that BBN constraints on hadronic annihilation channels are competitive with similar bounds derived from the cosmic microwave background.

  4. Big bang nucleosynthesis as a probe of fundamental "constants"

    E-Print Network [OSTI]

    Thomas Dent; Steffen Stern

    2007-10-25

    Big Bang nucleosynthesis (BBN) is the earliest sensitive probe of the values of many fundamental particle physics parameters. We have found the leading linear dependences of primordial abundances on all relevant parameters of the standard BBN code, including binding energies and nuclear reaction rates. This enables us to set limits on possible variations of fundamental parameters. We find that 7Li is expected to be significantly more sensitive than other species to many fundamental parameters, a result which also holds for variations of coupling strengths in grand unified (GUT) models. Our work also indicates which areas of nuclear theory need further development if the values of ``constants'' are to be more accurately probed.

  5. Big bang nucleosynthesis revisited via Trojan Horse method measurements

    SciTech Connect (OSTI)

    Pizzone, R. G.; Spartá, R.; Spitaleri, C.; La Cognata, M.; Tumino, A. [INFN—Laboratori Nazionali del Sud, Via Santa Sofia 62, I-95123 Catania (Italy); Bertulani, C. A.; Lalmansingh, J. [Department of Physics and Astronomy, Texas A and M University, Commerce, TX 75025 (United States); Lamia, L. [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania, Via Santa Sofia 64, I-95123 Catania (Italy); Mukhamedzhanov, A., E-mail: rgpizzone@lns.infn.it [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States)

    2014-05-10

    Nuclear reaction rates are among the most important input for understanding primordial nucleosynthesis and, therefore, for a quantitative description of the early universe. An up-to-date compilation of direct cross-sections of {sup 2}H(d, p){sup 3}H, {sup 2}H(d, n){sup 3}He, {sup 7}Li(p, ?){sup 4}He, and {sup 3}He(d, p){sup 4}He reactions is given. These are among the most uncertain cross-sections used and input for big bang nucleosynthesis calculations. Their measurements through the Trojan Horse method are also reviewed and compared with direct data. The reaction rates and the corresponding recommended errors in this work were used as input for primordial nucleosynthesis calculations to evaluate their impact on the {sup 2}H, {sup 3,4}He, and {sup 7}Li primordial abundances, which are then compared with observations.

  6. Primordial Lithium Abundance in Catalyzed Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Chris Bird; Kristen Koopmans; Maxim Pospelov

    2008-05-19

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

  7. Dark/visible parallel universes and Big Bang nucleosynthesis

    SciTech Connect (OSTI)

    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)

    2012-11-20

    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.

  8. Big Bang Nucleosynthesis with Independent Neutrino Distribution Functions

    E-Print Network [OSTI]

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

    2008-12-06

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

  9. Standard big bang nucleosynthesis and primordial CNO abundances after Planck

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS/IN2P3, Université Paris Sud 11, UMR 8609, Bâtiment 104, F–91405 Orsay Campus (France); Uzan, Jean-Philippe; Vangioni, Elisabeth, E-mail: coc@csnsm.in2p3.fr, E-mail: uzan@iap.fr, E-mail: vangioni@iap.fr [Institut d'Astrophysique de Paris, UMR-7095 du CNRS, Université Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris (France)

    2014-10-01

    Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. The recent results by the Planck satellite mission have slightly changed the estimate of the baryonic density compared to the previous WMAP analysis. This article updates the BBN predictions for the light elements using the cosmological parameters determined by Planck, as well as an improvement of the nuclear network and new spectroscopic observations. There is a slight lowering of the primordial Li/H abundance, however, this lithium value still remains typically 3 times larger than its observed spectroscopic abundance in halo stars of the Galaxy. According to the importance of this ''lithium problem{sup ,} we trace the small changes in its BBN calculated abundance following updates of the baryonic density, neutron lifetime and networks. In addition, for the first time, we provide confidence limits for the production of {sup 6}Li, {sup 9}Be, {sup 11}B and CNO, resulting from our extensive Monte Carlo calculation with our extended network. A specific focus is cast on CNO primordial production. Considering uncertainties on the nuclear rates around the CNO formation, we obtain CNO/H ? (5-30)×10{sup -15}. We further improve this estimate by analyzing correlations between yields and reaction rates and identified new influential reaction rates. These uncertain rates, if simultaneously varied could lead to a significant increase of CNO production: CNO/H?10{sup -13}. This result is important for the study of population III star formation during the dark ages.

  10. Inhomogeneous big bang nucleosynthesis with late-decaying massive particles

    E-Print Network [OSTI]

    J. Lopez-Suarez; R. Canal

    1998-04-22

    We investigate the possibility of accounting for the currently inferred primordial abundances of D, 3He, 4He, and 7Li by big bang nucleosynthesis in the presence of baryon density inhomogeneities plus the effects of late-decaying massive particles (X), and we explore the allowed range of baryonic fraction of the closure density Omega_b in such context. We find that, depending on the parameters of this composite model (characteristic size and density contrast of the inhomogeneities; mass-density, lifetime, and effective baryon number in the decay of the X-particles), values as high as \\Omega_{b}h_{50}^{2}\\simeq 0.25-0.35 could be compatible with the primordial abundances of the light nuclides. We include diffusion of neutrons and protons at all stages, and we consider the contribution of the X particles to the energy density, the entropy production by their decay, the possibility that the X-products could photodissociate the light nuclei produced during the previous stages of nucleosynthesis, and also the possibility that the decay products of the X-particles would include a substantial fraction of hadrons. Specific predictions for the primordial abundance of Be are made.

  11. Effect of quark-mass variation on big bang nucleosynthesis

    E-Print Network [OSTI]

    J. C. Berengut; V. F. Dmitriev; V. V. Flambaum

    2009-07-14

    We calculate the effect of variation in the light-current quark mass, $m_q$, on standard big bang nucleosynthesis. A change in $m_q$ at during the era of nucleosynthesis affects nuclear reaction rates, and hence primordial abundances, via changes the binding energies of light nuclei. It is found that a relative variation of $\\delta m_q/m_q = 0.016 \\pm 0.005$ provides better agreement between observed primordial abundances and those predicted by theory. This is largely due to resolution of the existing discrepancies for 7Li. However this method ignores possible changes in the position of resonances in nuclear reactions. The predicted 7Li abundance has a strong dependence on the cross-section of the resonant reactions 3He(d,p)4He and t(d,n)4He. We show that changes in $m_q$ at the time of BBN could shift the position of these resonances away from the Gamow window and lead to an increased production of 7Li, exacerbating the lithium problem.

  12. Dark Radiation from Particle Decays during Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Menestrina, Justin L

    2011-01-01

    Cosmic microwave background (CMB) observations suggest the possibility of an extra dark radiation component, while the current evidence from big bang nucleosynthesis (BBN) is more ambiguous. Dark radiation from a decaying particle can affect these two processes differently. Early decays add an additional radiation component to both the CMB and BBN, while late decays can alter the radiation content seen in the CMB while having a negligible effect on BBN. Here we quantify this difference and explore the intermediate regime by examining particles decaying during BBN, i.e., particle lifetimes \\tau_X satisfying 0.1 sec 1000 sec), \\Delta N_{BBN} is dominated by the energy density of the nonrelativistic particles before they decay, so that \\Delta N_{BBN} remains nonzero and becomes independent of the particle lifetime. By varying both the particle energy density and lifetime, one can obtain any desired combination of \\Delta N_{BBN} and \\Delta N_{CMB}, subject to the constraint that \\Delta N_{CMB} >= \\Delta N_{BBN}.

  13. The NACRE Thermonuclear Reaction Compilation and Big Bang Nucleosynthesis

    E-Print Network [OSTI]

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

    2001-05-17

    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.

  14. Constraint on slepton intergenerational mixing from big-bang nucleosynthesis

    SciTech Connect (OSTI)

    Kohri, Kazunori; Ohta, Shingo; Sato, Joe; Shimomura, Takashi; Yamanaka, Masato [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Department of Physics, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570 (Japan); Department of Physics, Niigata University, Niigata, 950-8502 (Japan) and Max-Planck-Institut fur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Maskawa Institute for Science and Culture, Kyoto Sangyo University, Kyoto 603-8555 (Japan)

    2012-07-27

    We find constraint on intergenerational mixing of slepton from big-bang nucleosynthesis (BBN). Today, we know that there exist lepton flavor violation (LFV) from the observation of neutrino oscillation, though there do not exist LFV in the standard model of particle physics (SM). LFV in charged lepton sector (cLFV) have also been expected to exist. From theoretical point of view, the effects of long-lived stau on BBN have been investigated and it is known that the stau can solve the cosmological 7Li problem. However, in the study so far, tau flavor is exactly conserved and it contradict with the existence of cLFV. In this study, we generalize the flavor to be violated and call the stau as slepton. Even if the violation is tiny, it drastically changes the lifetime and the evolution of relic density of the slepton. Thus we analyze the effects of the long-lived slepton on BBN, and constrain the magnitude of the cLFV.

  15. Big Bang Nucleosynthesis and the Helium Isotope Ratio

    E-Print Network [OSTI]

    Cooke, Ryan

    2015-01-01

    The conventional approach to search for departures from the standard model of physics during Big Bang Nucleosynthesis involves a careful, and subtle measurement of the mass fraction of baryons consisting of helium. Recent measurements of this quantity tentatively support new physics beyond the standard model but, historically, this method has suffered from hidden systematic uncertainties. In this letter, I show that a combined measurement of the primordial deuterium abundance and the primordial helium isotope ratio has the potential to provide a complementary and reliable probe of new physics beyond the standard model. Using the recent determination of the primordial deuterium abundance and assuming that the measured pre-solar 3He/4He meteoritic abundance reflects the primordial value, a bound can be placed on the effective number of neutrino species, Neff(BBN) = 3.01 (+0.95 -0.76, with 95 per cent confidence). Although this value of Neff supports the standard model, it is presently unclear if the pre-solar 3...

  16. Big Bang Nucleosynthesis and the Helium Isotope Ratio

    E-Print Network [OSTI]

    Ryan Cooke

    2015-10-09

    The conventional approach to search for departures from the standard model of physics during Big Bang Nucleosynthesis involves a careful, and subtle measurement of the mass fraction of baryons consisting of helium. Recent measurements of this quantity tentatively support new physics beyond the standard model but, historically, this method has suffered from hidden systematic uncertainties. In this letter, I show that a combined measurement of the primordial deuterium abundance and the primordial helium isotope ratio has the potential to provide a complementary and reliable probe of new physics beyond the standard model. Using the recent determination of the primordial deuterium abundance and assuming that the measured pre-solar 3He/4He meteoritic abundance reflects the primordial value, a bound can be placed on the effective number of neutrino species, Neff(BBN) = 3.01 (+0.95 -0.76, with 95 per cent confidence). Although this value of Neff supports the standard model, it is presently unclear if the pre-solar 3He/4He ratio reflects the primordial value. New astrophysical measurements of the helium isotope ratio in near-pristine environments, together with updated calculations and experimental values of several important nuclear reactions (some of which are already being attempted), will lead to much improved limits on possible departures from the standard model. To this end, I describe an analysis strategy to measure the 3He I flux emitted from nearby low metallicity H II regions. The proposed technique can be attempted with the next generation of large telescopes, and will be easier to realize in metal-poor H II regions with quiescent kinematics.

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

    E-Print Network [OSTI]

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

    2008-03-24

    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.

  18. Non-universal scalar-tensor theories and big bang nucleosynthesis

    E-Print Network [OSTI]

    Alain Coc; Keith A. Olive; Jean-Philippe Uzan; Elisabeth Vangioni

    2008-11-12

    We investigate the constraints that can be set from big-bang nucleosynthesis on two classes of models: extended quintessence and scalar-tensor theories of gravity in which the equivalence principle between standard matter and dark matter is violated. In the latter case, and for a massless dilaton with quadratic couplings, the phase space of theories is investigated. We delineate those theories where attraction toward general relativity occurs. It is shown that big-bang nucleosynthesis sets more stringent constraints than those obtained from Solar system tests.

  19. 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

  20. Big Bang Nucleosynthesis Constraints on the Self-Gravity of Pressure

    E-Print Network [OSTI]

    Saul Rappaport; Josiah Schwab; Scott Burles; Gary Steigman

    2007-10-28

    Using big bang nucleosynthesis and present, high-precision measurements of light element abundances, we constrain the self-gravity of radiation pressure in the early universe. The self-gravity of pressure is strictly non-Newtonian, and thus the constraints we set provide a direct test of this prediction of general relativity and of the standard, Robertson-Walker-Friedmann cosmology.

  1. Dark matter relic abundance and big bang nucleosynthesis in Horava's gravity

    SciTech Connect (OSTI)

    Lambiase, G. [University of Salerno (Italy); INFN, Sezione di Napoli (Italy)

    2011-05-15

    The cosmological consequences of Horava's gravity are reviewed in the frameworks of the PAMELA experiment (which has reported an excess of positron events that likely can be ascribed to weakly interacting massive particles dark matter) and of big bang nucleosynthesis. Constraints on parameters characterizing Horawa's cosmology are derived.

  2. Constraints on the Self-Gravity of Radiation Pressure via Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Saul Rappaport; Josiah Schwab; Scott Burles

    2007-07-24

    Using standard big-bang nucleosynthesis and present, high-precision measurements of light element abundances, we place constraints on the self-gravity of radiation pressure in the early universe. The self-gravity of pressure is strictly non-Newtonian, and thus the constraints we set are a direct test of this aspect of general relativity.

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

    SciTech Connect (OSTI)

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

    2014-05-02

    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.

  4. Constraints on unparticle long range forces from big bang nucleosynthesis bounds on the variation of the gravitational coupling

    E-Print Network [OSTI]

    O. Bertolami; N. M. C. Santos

    2009-06-18

    We use big bang nucleosynthesis bounds on the variation of the gravitational coupling to derive constraints on the strength of the deviation from the gravitational inverse-square law due to tensor and vector unparticle exchange.

  5. A Big-Bang Nucleosynthesis Limit on the Neutral Fermion Decays into Neutrinos

    E-Print Network [OSTI]

    Motohiko Kusakabe; A. B. Balantekin; Toshitaka Kajino; Y. Pehlivan

    2013-04-09

    Using the primordial helium abundance, an upper limit to the magnetic moments for Dirac neutrinos had been provided by imposing restrictions on the number of the additional helicity states. Considering non-thermal photons produced in the decay of the heavy sterile mass eigenstates due to the neutrino magnetic moment, we explore the constraints imposed by the observed abundances of all the light elements produced during the Big Bang nucleosynthesis.

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

    SciTech Connect (OSTI)

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

    2012-11-12

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

  7. n+p -> d+gamma for Big-Bang Nucleosynthesis

    E-Print Network [OSTI]

    Jiunn-Wei Chen; Martin J. Savage

    1999-07-09

    The cross section for n+p -> d+gamma is calculated at energies relevant to big bang nucleosynthesis using the recently developed effective field theory that describes the two-nucleon sector. The E1 amplitude is computed up to NNNLO and depends only upon nucleon-nucleon phase shift data. In contrast, the M1 contribution is computed up to NLO, and the four-nucleon-one-magnetic-photon counterterm that enters is determined by the cross section for cold neutron capture. The uncertainty in the calculation for nucleon energies up to E ~ 1 MeV is estimated to be < 4%.

  8. Corrected constraints on big bang nucleosynthesis in a modified gravity model of $f(R) \\propto R^n$

    E-Print Network [OSTI]

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

    2015-01-01

    Big bang nucleosynthesis in a modified gravity model of $f(R)\\propto R^n$ is investigated. The only free parameter of the model is a power-law index $n$. We find cosmological solutions in a parameter region of $1big bang nucleosynthesis. We compare the results with the latest observational data. It is then found that the power-law index is constrained to be $(n-1)=(-0.86\\pm 1.19)\\times 10^{-4}$ (95 % C.L.) mainly from observations of deuterium abundance as well as $^4$He abundance.

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

    SciTech Connect (OSTI)

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

    2012-01-10

    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.

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

    E-Print Network [OSTI]

    David L. Lambert

    2004-10-18

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

  11. Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles

    E-Print Network [OSTI]

    Karsten Jedamzik

    2006-11-10

    Big Bang nucleosynthesis in the presence of decaying relic neutral particles is examined in detail. All non-thermal processes important for the determination of light-element abundance yields of 2H, 3H, 3He, 4He, 6Li, and 7Li 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 < tau < 10^(12) sec. Decaying particles are typically constrained at early times by 4He or 2H, at intermediate times by 6Li, and at large times by the 3He/2H 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.

  12. Big bang nucleosynthesis constrains the total annihilation cross section of neutralino dark matter

    E-Print Network [OSTI]

    Xiao-Jun Bi

    2008-04-17

    Assuming the lightest neutralino forms dark matter, we study its residual annihilation after freeze-out at the early universe. If taking place after the big bang nucleosynthesis (BBN) the annihilation products, especially at the hadronic modes, may cause nonthermal nuclear reaction and change the prediction of the primordial abundance of light elements in the standard BBN scenario. We therefore put constraints on the neutralino annihilation cross section. These constraints are free of the uncertainties of the dark matter profile today suffered by direct or indirect detection of dark matter. We find the constraints by BBN is important, especially when taking large $\\tan\\beta$. If the light element abundances can be determined with higher precision in the future the constraint will become very strong, so that a majority of the parameter space allowed by the relic density requirement may be excluded.

  13. Constraining scalar dark matter with Big Bang nucleosynthesis and atomic spectroscopy

    E-Print Network [OSTI]

    Stadnik, Y V

    2015-01-01

    Scalar dark matter can interact with Standard Model (SM) particles, altering the fundamental constants of Nature in the process. Changes in the fundamental constants during and before Big Bang nucleosynthesis (BBN) produce changes in the primordial abundances of the light elements. In particular, the primordial abundance of $^{4}$He is predominantly determined by the ratio of the neutron-proton mass difference to freeze-out temperature at the time of the weak interaction freeze-out prior to BBN, which is a sensitive function of the fundamental constants. By comparing the measured and calculated (within the SM) primordial abundance of $^{4}$He, we are able to derive stringent constraints on the mass of a scalar dark matter particle $\\phi$ together with its interactions with photons, light quarks and massive vector bosons via linear and quadratic couplings in $\\phi$. We also derive constraints on the quadratic interaction of $\\phi$ with photons from recent atomic dysprosium spectroscopy measurements.

  14. Constraining scalar dark matter with Big Bang nucleosynthesis and atomic spectroscopy

    E-Print Network [OSTI]

    Y. V. Stadnik; V. V. Flambaum

    2015-04-12

    Scalar dark matter can interact with Standard Model (SM) particles, altering the fundamental constants of Nature in the process. Changes in the fundamental constants during and prior to Big Bang nucleosynthesis (BBN) produce changes in the primordial abundances of the light elements. By comparing the measured and calculated (within the SM) primordial abundance of $^{4}$He, which is predominantly determined by the ratio of the neutron-proton mass difference to freeze-out temperature at the time of weak interaction freeze-out prior to BBN, we are able to derive stringent constraints on the mass of a scalar dark matter particle $\\phi$ together with its interactions with the photon, light quarks and massive vector bosons via quadratic couplings in $\\phi$, as well as its interactions with massive vector bosons via linear couplings in $\\phi$. We also derive a stringent constraint on the quadratic interaction of $\\phi$ with the photon from recent atomic dysprosium spectroscopy measurements.

  15. Limits on Cosmological Variation of Strong Interaction and Quark Masses from Big Bang Nucleosynthesis, Cosmic, Laboratory and Oklo Data

    E-Print Network [OSTI]

    V. V. Flambaum; E. V. Shuryak

    2002-02-18

    Recent data on cosmological variation of the electromagnetic fine structure constant from distant quasar (QSO) absorption spectra have inspired a more general discussion of possible variation of other constants. We discuss variation of strong scale and quark masses. We derive the limits on their relative change from (i) primordial Big-Bang Nucleosynthesis (BBN); (ii) Oklo natural nuclear reactor, (iii) quasar absorption spectra, and (iv) laboratory measurements of hyperfine intervals.

  16. Constraints on modified Gauss-Bonnet gravity during big bang nucleosynthesis

    E-Print Network [OSTI]

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

    2015-01-01

    The modified gravity is considered to be one of possible explanations of the accelerated expansions of the present and the early universe. We study effects of the modified gravity on big bang nucleosynthesis (BBN). If effects of the modified gravity are significant during the BBN epoch, they should be observed as changes of primordial light element abundances. We assume a $f(G)$ term with the Gauss-Bonnet term $G$, during the BBN epoch. A power-law relation of $df/dG \\propto t^p$ where $t$ is the cosmic time was assumed for the function $f(G)$ as an example case. We solve time evolutions of physical variables during BBN in the $f(G)$ gravity model numerically, and analyzed calculated results. It is found that a proper solution for the cosmic expansion rate can be lost in some parameter region. In addition, we show that calculated results of primordial light element abundances can be significantly different from observational data. Especially, observational limits on primordial D abundance leads to the stronge...

  17. Big Bang nucleosynthesis in scalar tensor gravity: the key problem of the $^7$Li abundance

    E-Print Network [OSTI]

    Julien Larena; Jean-Michel Alimi; Arturo Serna

    2006-11-20

    Combined with other CMB experiments, the WMAP survey provides an accurate estimate of the baryon density of the Universe. In the framework of the standard Big Bang Nucleosynthesis (BBN), such a baryon density leads to predictions for the primordial abundances of $^{4}$He and D in good agreement with observations. However, it also leads to a significant discrepancy between the predicted and observed primordial abundance of $^{7}$Li. Such a discrepancy is often termed as 'the lithium problem'. In this paper, we analyze this problem in the framework of scalar-tensor theories of gravity. It is shown that an expansion of the Universe slightly slower than in General Relativity before BBN, but faster during BBN, solves the lithium problem and leads to $^4$He and D primordial abundances consistent with the observational constraints. This kind of behavior is obtained in numerous scalar-tensor models, both with and without a self-interaction potential for the scalar field. In models with a self-interacting scalar field, the convergence towards General Relativity is ensured without any condition, thanks to an attraction mechanism which starts to work during the radiation-dominated epoch.

  18. Effect of Long-lived Strongly Interacting Relic Particles on Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Motohiko Kusakabe; Toshitaka Kajino; Takashi Yoshida; Grant J. Mathews

    2009-06-18

    It has been suggested that relic long-lived strongly interacting massive particles (SIMPs, or $X$ particles) existed in the early universe. We study effects of such long-lived unstable SIMPs on big bang nucleosynthesis (BBN) assuming that such particles existed during the BBN epoch, but then decayed long before they could be detected. The interaction strength between an $X$ particle and a nucleon is assumed to be similar to that between nucleons. We then calculate BBN in the presence of the unstable neutral charged $X^0$ particles taking into account the capture of $X^0$ particles by nuclei to form $X$-nuclei. We also study the nuclear reactions and beta decays of $X$-nuclei. We find that SIMPs form bound states with normal nuclei during a relatively early epoch of BBN. This leads to the production of heavy elements which remain attached to them. Constraints on the abundance of $X^0$ particles during BBN are derived from observationally inferred limits on the primordial light element abundances. Particle models which predict long-lived colored particles with lifetimes longer than $\\sim$ 200 s are rejected based upon these constraints.

  19. Constraints on modified Gauss-Bonnet gravity during big bang nucleosynthesis

    E-Print Network [OSTI]

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

    2015-07-20

    The modified gravity is considered to be one of possible explanations of the accelerated expansions of the present and the early universe. We study effects of the modified gravity on big bang nucleosynthesis (BBN). If effects of the modified gravity are significant during the BBN epoch, they should be observed as changes of primordial light element abundances. We assume a $f(G)$ term with the Gauss-Bonnet term $G$, during the BBN epoch. A power-law relation of $df/dG \\propto t^p$ where $t$ is the cosmic time was assumed for the function $f(G)$ as an example case. We solve time evolutions of physical variables during BBN in the $f(G)$ gravity model numerically, and analyzed calculated results. It is found that a proper solution for the cosmic expansion rate can be lost in some parameter region. In addition, we show that calculated results of primordial light element abundances can be significantly different from observational data. Especially, observational limits on primordial D abundance leads to the strongest constraint on the $f(G)$ gravity. We then derive constraints on parameters of the $f(G)$ gravity taking into account the existence of the solution of expansion rate and final light element abundances.

  20. Effects of power law primordial magnetic field on big bang nucleosynthesis

    E-Print Network [OSTI]

    Dai G. Yamazaki; Motohiko Kusakabe

    2012-12-12

    Big bang nucleosynthesis (BBN) is affected by the energy density of a primordial magnetic field (PMF). For an easy derivation of constraints on models for PMF generations, we assume a PMF with a power law (PL) distribution in wave number defined with a field strength, a PL index, and maximum and minimum scales at a generation epoch. We then show a relation between PL-PMF parameters and the scale invariant (SI) strength of PMF for the first time. We perform a BBN calculation including PMF effects, and show abundances as a function of baryon to photon ratio $\\eta$. The SI strength of the PMF is constrained from observational constraints on abundances of $^4$He and D. The minimum abundance of $^7$Li/H as a function of $\\eta$ slightly moves to a higher $^7$Li/H value at a larger $\\eta$ value when a PMF exists during BBN. We then discuss degeneracies between the PL-PMF parameters in the PMF effect. In addition, we assume a general case in which both the existence and the dissipation of PMF are possible. It is then found that an upper limit on the SI strength of the PMF can be derived from a constraint on $^4$He abundance, and that a lower limit on the allowed $^7$Li abundance is significantly higher than those observed in metal-poor stars.

  1. Corrected constraints on big bang nucleosynthesis in a modified gravity model of $f(R) \\propto R^n$

    E-Print Network [OSTI]

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

    2015-06-29

    Big bang nucleosynthesis in a modified gravity model of $f(R)\\propto R^n$ is investigated. The only free parameter of the model is a power-law index $n$. We find cosmological solutions in a parameter region of $1nucleosynthesis. We compare the results with the latest observational data. It is then found that the power-law index is constrained to be $(n-1)=(-0.86\\pm 1.19)\\times 10^{-4}$ (95 % C.L.) mainly from observations of deuterium abundance as well as $^4$He abundance.

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

    SciTech Connect (OSTI)

    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)

    2014-05-02

    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.

  3. Arnett, D. 1996, Supernovae and Nucleosynthesis: An Investigation of the History of Matter, from the Big Bang to the Present. Princeton: Princeton University Press.

    E-Print Network [OSTI]

    Mamajek, Eric E.

    of Matter, from the Big Bang to the Present. Princeton: Princeton University Press. Carroll, B. W., & Ostlie, Principles of Stellar Evolution and Nucleosynthesis. Chicago: University of Chicago Press. Collins, G. W, The Observation and Analysis of Stellar Photospheres, 3rd ed. Cambridge, UK: Cambridge University Press. Hansen, C

  4. Bino Dark Matter and Big Bang Nucleosynthesis in the Constrained E6SSM with Massless Inert Singlinos

    E-Print Network [OSTI]

    Jonathan P. Hall; Stephen F. King

    2011-05-11

    We discuss a new variant of the E6 inspired supersymmetric standard model (E6SSM) in which the two inert singlinos are exactly massless and the dark matter candidate has a dominant bino component. A successful relic density is achieved via a novel mechanism in which the bino scatters inelastically into heavier inert Higgsinos during the time of thermal freeze-out. The two massless inert singlinos contribute to the effective number of neutrino species at the time of Big Bang Nucleosynthesis, where the precise contribution depends on the mass of the Z' which keeps them in equilibrium. For example for mZ' > 1300 GeV we find Neff \\approx 3.2, where the smallness of the additional contribution is due to entropy dilution. We study a few benchmark points in the constrained E6SSM with massless inert singlinos to illustrate this new scenario.

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

    E-Print Network [OSTI]

    H. F. Santana Mota; Mark Hindmarsh

    2015-01-06

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

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

    E-Print Network [OSTI]

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

    2015-01-01

    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...

  7. Big Bang Nucleosynthesis with Bound States of Long-lived Charged Particles

    E-Print Network [OSTI]

    Manoj Kaplinghat; Arvind Rajaraman

    2007-01-18

    Charged particles (X) decaying after primordial nucleosynthesis are constrained by the requirement that their decay products should not change the light element abundances drastically. If the decaying particle is negatively charged (X-) then it will bind to the nuclei. We consider the effects of the decay of X when bound to Helium-4 and show that this will modify the Lithium abundances.

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

    E-Print Network [OSTI]

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

    2015-02-13

    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.

  9. Primordial nucleosynthesis and neutrino physics

    E-Print Network [OSTI]

    Smith, Christel Johanna

    2009-01-01

    Chapter 4 Big Bang Nucleosynthesis Weak Rate1 1.1.2 Big Bang Nucleosynthesis . . . . . . . . . . . . .5 1.1.3 Nucleosynthesis Predictions and Comparison to

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

    SciTech Connect (OSTI)

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

    2014-09-01

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

  11. Precision Measurements of d(d,p)t and d(d,n)^3He Total Cross Sections at Big-Bang Nucleosynthesis Energies

    E-Print Network [OSTI]

    D. S. Leonard; H. J. Karwowski; C. R. Brune; B. M. Fisher; E. J. Ludwig

    2006-06-01

    Recent Wilkinson Microwave Anisotropy Probe (WMAP) measurements have determined the baryon density of the Universe $\\Omega_b$ with a precision of about 4%. With $\\Omega_b$ tightly constrained, comparisons of Big Bang Nucleosynthesis (BBN) abundance predictions to primordial abundance observations can be made and used to test BBN models and/or to further constrain abundances of isotopes with weak observational limits. To push the limits and improve constraints on BBN models, uncertainties in key nuclear reaction rates must be minimized. To this end, we made new precise measurements of the d(d,p)t and d(d,n)^3He total cross sections at lab energies from 110 keV to 650 keV. A complete fit was performed in energy and angle to both angular distribution and normalization data for both reactions simultaneously. By including parameters for experimental variables in the fit, error correlations between detectors, reactions, and reaction energies were accurately tabulated by computational methods. With uncertainties around 2% +/- 1% scale error, these new measurements significantly improve on the existing data set. At relevant temperatures, using the data of the present work, both reaction rates are found to be about 7% higher than those in the widely used Nuclear Astrophysics Compilation of Reaction Rates (NACRE). These data will thus lead not only to reduced uncertainties, but also to modifications in the BBN abundance predictions.

  12. Destructions of {sup 7}Be and {sup 7}Li in Big Bang nucleosynthesis through reactions with exotic long-lived sub-strongly interacting massive particles

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Kawasaki, Masahiro [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan and Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan)

    2012-11-12

    An observed plateau abundance of {sup 7}Li in metal-poor halo stars indicates its primordial origin. The {sup 7}Li abundances are about a factor of three smaller than that predicted in standard big bang nucleosynthesis (BBN) model. In addition, some of the stars possibly contain {sup 6}Li in abundances larger than standard BBN prediction. Particle models sometimes include heavy longlived colored particles which are confined in exotic strongly interacting massive particles (SIMPs). We have found reactions which destroy {sup 7}Be and {sup 7}Li during BBN in the scenario of BBN affected by a long-lived sub-strongly interactingmassive particle (sub-SIMP, X). The reactions are non radiative X captures of {sup 7}Be and {sup 7}Li which can operate if the X particle interacts with nuclei strongly enough to drive {sup 7}Be destruction but not strongly enough to form a bound state with {sup 4}He of relative angular momentum L = 1. The processes can be a cause of the {sup 7}Li problem. In this paper we suggest new possible reactions for {sup 6}Li production. Especially, a {sup 6}Li production through the deuteron capture of {sup 4}He bound to X can operate in the parameter region solving the {sup 7}Li problem.

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

    E-Print Network [OSTI]

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

    2010-11-29

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

  14. A different Big Bang theory: Los Alamos

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

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

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

    E-Print Network [OSTI]

    David Thomas

    1994-12-11

    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.

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

    E-Print Network [OSTI]

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

    2015-01-01

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

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

    E-Print Network [OSTI]

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

    2004-07-06

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

  18. Space Time Quantization and the Big Bang

    E-Print Network [OSTI]

    B. G. Sidharth

    1998-06-21

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

  19. Meyer and Zinner: Nucleosynthesis 69 Nucleosynthesis

    E-Print Network [OSTI]

    Floss, Christine

    Meyer and Zinner: Nucleosynthesis 69 69 Nucleosynthesis Bradley S. Meyer Clemson University Ernst these topics in cosmochemistry and their implications for our ideas about stellar nucleosynthesis. 1 nucleosynthesis. After the Big Bang the universe consisted only of H and He and trace amounts of Li, Be, and B

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

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

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

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

    E-Print Network [OSTI]

    Alessandra Buonanno; Martin Lemoine; Keith A. Olive

    2000-09-27

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

  2. Big Bang Expansion A textbook example of how observations drive theory

    E-Print Network [OSTI]

    Korn, Andreas

    of structure seeds. The cosmic web will later form out of these sedes. #12;II. Observing the CMB Variations WMAP tot = 1 Dark matter: 23% Dark energy (): 73% #12;Big Bang: a self-consistent theory? Big Bang

  3. Electron Screening effect on the Big Bang Nucleosynthesis

    E-Print Network [OSTI]

    Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

    with great supports patiently on all aspects of this work. Carlos is one of best advisors around world I met and engineers to make a presentation in commerce which really broaden our outlook of research fields. This work was partially supported by the U.S. Department of Energy grants DE-FG02- 08ER41533, DE-FC02-07ER

  4. Lorentz Invariance Breakdown and Constraints from Big-Bang Nucleosynthesis

    E-Print Network [OSTI]

    G. Lambiase

    2005-10-13

    The Standard Model Extension formulated by Colladay and Kosteleck\\'y is reviewed in the framework of the $^4He$ primordial abundance. Upper bounds on coefficients for the Lorentz violation are derived using the present observational data.

  5. Quark mass variation constraints from Big Bang nucleosynthesis (Journal

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield MunicipalTechnical Report:Speeding access toSmall Reactor forPatentsConnectQ LA-UR-Article) |

  6. Quark mass variation constraints from Big Bang nucleosynthesis (Journal

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect Pulse energy measurement(Conference)Article) | SciTech

  7. Pre-big bang scenario and the WZW model

    E-Print Network [OSTI]

    Marcel Jacon

    2015-06-09

    Extensive studies of pre-big bang scenarios for Bianchi-I type universe have been made, at various approximation levels. Knowing the solution of the equations for the post-big bang universe, the symmetries of the equations (time reversal and scale dual transformations) allow the study of pre-big bang solutions. However, the proposed solutions are unable to explain the actually observed acceleration of the expantion of the universe.Calculating the $\\beta $ equations for the Non-Linear Sigma model, at the first loop approximation and imposing conformal invariance at this level, lead to equations of motion that simply state that the curvature must be nil, which in turn allows the utilization of groups to solve the $\\beta $ equations. This is what is done in the Weiss-Zumino-Witten (WZW) model. In this article, I will show that using the WZW model on $SU_2$, some of the difficulties encountered in the determination of the pre and post big-bang solutions are eliminated. Combining the general results obtained with the $\\Lambda $CDM parameters lead to realistic solutions for the evolution of the universe, giving an explanation to the actually observed acceleration of the expansion in terms ot the dilation field $\\phi $(t).

  8. Primordial Nucleosynthesis

    E-Print Network [OSTI]

    Alain Coc

    2012-08-23

    Primordial nucleosynthesis, or Big-Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor 3-5, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. We review here the nuclear physics aspects of BBN for the production of 4He, D, 3He and 7Li, but also 6Li, 9Be, 11B and up to CNO isotopes. These are, for instance, important for the initial composition of the matter at the origin of the first stars. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe, like variation of "constants" or alternative theories of gravity.

  9. Primordial beryllium as a big bang calorimeter

    E-Print Network [OSTI]

    Maxim Pospelov; Josef Pradler

    2011-03-23

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

  10. Primordial Beryllium as a Big Bang Calorimeter

    SciTech Connect (OSTI)

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

    2011-03-25

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

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

    ScienceCinema (OSTI)

    None

    2011-04-25

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

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

    ScienceCinema (OSTI)

    None

    2011-04-25

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

  13. Quantization of Big Bang in crypto-Hermitian Heisenberg picture

    E-Print Network [OSTI]

    Znojil, Miloslav

    2015-01-01

    A background-independent quantization of the Universe near its Big Bang singularity is considered using a drastically simplified toy model. Several conceptual issues are addressed. (1) The observable spatial-geometry characteristics of our empty-space expanding Universe is sampled by the time-dependent operator $Q=Q(t)$ of the distance between two space-attached observers (``Alice and Bob''). (2) For any pre-selected guess of the simple, non-covariant time-dependent observable $Q(t)$ one of the Kato's exceptional points (viz., $t=\\tau_{(EP)}$) is postulated {\\em real-valued}. This enables us to treat it as the time of Big Bang. (3) During our ``Eon'' (i.e., at all $t>\\tau_{(EP)}$) the observability status of operator $Q(t)$ is mathematically guaranteed by its self-adjoint nature with respect to an {\\em ad hoc} Hilbert-space metric $\\Theta(t) \

  14. Supernova bangs as a tool to study big bang

    SciTech Connect (OSTI)

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

    2012-09-15

    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.

  15. A Simple/Short Introduction to Pre-Big-Bang Physics/Cosmology

    E-Print Network [OSTI]

    G. Veneziano

    1998-03-02

    A simple, non-technical introduction to the pre-big bang scenario is given, emphasizing physical motivations, considerations, and consequences over formalism.

  16. Nucleosynthesis Without a Computer

    E-Print Network [OSTI]

    V. Mukhanov

    2003-03-04

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

  17. From (p)reheating to nucleosynthesis

    E-Print Network [OSTI]

    Karsten Jedamzik

    2001-12-10

    This article gives a brief qualitative description of the possible evolution of the early Universe between the end of an inflationary epoch and the end of Big Bang nucleosynthesis. After a general introduction, establishing the minimum requirements cosmologists impose on this cosmic evolutionary phase, namely, successful baryogenesis, the production of cosmic dark matter, and successful light-element nucleosynthesis, a more detailed discussion on some recent developments follows. This latter includes the physics of preheating, the putative production of (alternative) dark matter, and the current status of Big Bang nucleosynthesis.

  18. The Biological Big Bang: The First Oceans of Primordial Planets at 2-8 Million Years Explain Hoyle/Wickramasinghe Cometary Panspermia

    E-Print Network [OSTI]

    Gibson, Carl H

    2011-01-01

    Hydrogravitional-dynamics (HGD) cosmology of Gibson/Schild 1996 predicts that the primordial H-He^4 gas of big bang nucleosynthesis became proto-globular-star-cluster clumps of Earth-mass planets at 300 Kyr. The first stars formed from mergers of these 3000 K gas planets. Chemicals C, N, O, Fe etc. created by stars and supernovae then seeded many of the reducing hydrogen gas planets with oxides to give them hot water oceans with metallic iron-nickel cores. Water oceans at critical temperature 647 K then hosted the first organic chemistry and the first life, distributed to the 10^80 planets of the cosmological big bang by comets produced by the new (HGD) planet-merger star formation mechanism. The biological big bang scenario occurs between 2 Myr when liquid oceans condensed and 8 Myr when they froze. HGD cosmology explains, very naturally, the Hoyle/Wickramasinghe concept of cometary panspermia by giving a vast, hot, nourishing, cosmological primordial soup for abiogenesis, and the means for transmitting the ...

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

    E-Print Network [OSTI]

    H. Schade; B. Kampfer

    2009-03-30

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

  20. Primordial nucleosynthesis: A cosmological point of view

    SciTech Connect (OSTI)

    Mathews, G. J.; Kusakabe, M.; Cheoun, M.-K.

    2014-05-09

    Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the test-ing ground upon which all cosmological models must ultimately rest. It is our only probe of the universe during the first few minutes of cosmic expansion and in particular during the important radiation-dominated epoch. These lectures review the basic equations of space-time, cosmology, and big bang nucleosynthesis. We will then review the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measure-ments are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we summarize the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field.

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

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

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

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

    ScienceCinema (OSTI)

    None

    2011-04-25

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

  3. Constraining spacetime noncommutativity with primordial nucleosynthesis

    E-Print Network [OSTI]

    Raul Horvat; Josip Trampetic

    2009-04-01

    We discuss a constraint on the scale $\\Lambda_{\\rm NC}$ of noncommutative (NC) gauge field theory arising from consideration of the big bang nucleosynthesis (BBN) of light elements. The propagation of neutrinos in the NC background described by an antisymmetric tensor $\\theta^{\\mu\

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

    E-Print Network [OSTI]

    Fygenson, Deborah Kuchnir

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

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

    E-Print Network [OSTI]

    Fygenson, Deborah Kuchnir

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

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

    ScienceCinema (OSTI)

    Penrose, Roger

    2010-09-01

    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.

  7. 2014 Awarded Campaigns

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

    (Israel) Charged particle stopping powers Zylstra (MIT) Stellar and Big Bang nucleosynthesis Gatu-Johnson (MIT) Magnetogenesis and B field amplification Gregori (Oxford)...

  8. Out of the white hole: a holographic origin for the Big Bang

    SciTech Connect (OSTI)

    Pourhasan, Razieh; Afshordi, Niayesh; Mann, Robert B. E-mail: nafshordi@pitp.ca

    2014-04-01

    While most of the singularities of General Relativity are expected to be safely hidden behind event horizons by the cosmic censorship conjecture, we happen to live in the causal future of the classical Big Bang singularity, whose resolution constitutes the active field of early universe cosmology. Could the Big Bang be also hidden behind a causal horizon, making us immune to the decadent impacts of a naked singularity? We describe a braneworld description of cosmology with both 4d induced and 5D bulk gravity (otherwise known as Dvali-Gabadadze-Porati, or DGP model), which exhibits this feature: the universe emerges as a spherical 3-brane out of the formation of a 5D Schwarzschild black hole. In particular, we show that a pressure singularity of the holographic fluid, discovered earlier, happens inside the white hole horizon, and thus need not be real or imply any pathology. Furthermore, we outline a novel mechanism through which any thermal atmosphere for the brane, with comoving temperature of ?20% of the 5D Planck mass can induce scale-invariant primordial curvature perturbations on the brane, circumventing the need for a separate process (such as cosmic inflation) to explain current cosmological observations. Finally, we note that 5D space-time is asymptotically flat, and thus potentially allows an S-matrix or (after minor modifications) an AdS/CFT description of the cosmological Big Bang.

  9. Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination

    E-Print Network [OSTI]

    Wayne Hu

    2008-02-25

    These lecture notes comprise an informal but pedagogical introduction to the well established physics and phenomenology of the cosmic microwave background (CMB) between big bang nucleosynthesis and recombination. The dominant properties of the spectrum, temperature anisotropy and polarization anisotropy of the CMB all arise from this period. We review the physical processes involved and show how they are related to the observed phenomenology.

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

    E-Print Network [OSTI]

    Ninetta Saviano; Ofelia Pisanti; Gianpiero Mangano; Alessandro Mirizzi

    2014-11-15

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

  11. Big Bang Nucleosynthesis, Implications of Recent CMB Data and Supersymmetric Dark Matter

    E-Print Network [OSTI]

    Keith A. Olive

    2002-03-01

    The BBN predictions for the abundances of the light element isotopes is reviewed and compared with recent observational data. The single unknown parameter of standard BBN is the baryon-to-photon ratio, \\eta, and can be determined by the concordance between theory and observation. Recent CMB anisotropy measurements also lead to a determination of \\eta and these results are contrasted with those from BBN. In addition, the CMB data indicate that the Universe is spatially flat. Thus it is clear that some form of non-baryonic dark matter or dark energy is necessary. Here I will also review the current expectations for cold dark matter from minimal supersymmetric models. The viability of detecting supersymmetric dark matter will also be discussed.

  12. An origin of the universe: a model alternative to Big Bang

    E-Print Network [OSTI]

    Andrzej Mercik; Szymon Mercik

    2006-04-04

    We propose a new approach to the model of an origin of the universe built by Oscar Klein and Hannes Alfv\\'{e}n. Some modifications of assumptions underlying the model result in a possible scenario of the universe creation consistent with observations. We explain the large scale structre of the universe and we estimate the Hubble constant value as well as the number of galaxies in the universe. The model does not require many assumptions made in the model based on the Big Bang idea.

  13. Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity

    E-Print Network [OSTI]

    V. G. Gurzadyan; R. Penrose

    2010-11-16

    Conformal cyclic cosmology (CCC) posits the existence of an aeon preceding our Big Bang 'B', whose conformal infinity 'I' is identified, conformally, with 'B', now regarded as a spacelike 3-surface. Black-hole encounters, within bound galactic clusters in that previous aeon, would have the observable effect, in our CMB sky, of families of concentric circles over which the temperature variance is anomalously low, the centre of each such family representing the point of 'I' at which the cluster converges. These centres appear as fairly randomly distributed fixed points in our CMB sky. The analysis of Wilkinson Microwave Background Probe's (WMAP) cosmic microwave background 7-year maps does indeed reveal such concentric circles, of up to 6{\\sigma} significance. This is confirmed when the same analysis is applied to BOOMERanG98 data, eliminating the possibility of an instrumental cause for the effects. These observational predictions of CCC would not be easily explained within standard inflationary cosmology.

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

    ScienceCinema (OSTI)

    Smoot, George

    2011-04-28

    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.

  15. Relic High Frequency Gravitational waves from the Big Bang, and How to Detect Them

    E-Print Network [OSTI]

    A. W. Beckwith

    2009-01-14

    We show conditions for HFGW detection, employing an entropy concept written up by Jack Ng, and Steinhard's proceedure for reconstructing tensorial representations for relic HFGW from the onset of the big bang. The issue of the reality of gravitons as a measurable physical object which was raised by Rothman in 2006 is indirectly answered via a proceedure obtained from Weinberg's 1972 book on gravitation, and all the methodologies so obtained are referenced with respect to engineering specifications of the Li-Baker HFGW detector. In addition, the document also refers to entanglement entropy, and its possible aid in refining measurement predictions. Finally, commentary about HFGW and relic neutrino physics data sets is included, with regards to inflationary model candidates

  16. Nucleosynthesis in a simmering univeerse

    E-Print Network [OSTI]

    Daksh Lohiya; Annu Batra; Shobhit Mahajan; Amitabha Mukherjee

    1998-08-11

    Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We explore nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time right through the period during which nucleosynthesis occurs till the present. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding (weak interaction decoupling) temperature in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metalicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and the age problems and consistency with classical cosmological tests.

  17. Nucleosynthesis in a Simmering Universe

    E-Print Network [OSTI]

    Daksh Lohiya; Shobhit Mahajan; A. Mukherjee; Annu Batra

    1996-06-13

    Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We demonstrate nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time from the period during which nucleosynthesis occurs. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding temperatures in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metallicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and initial singularity problems, consistency with the age of globular clusters and consistent relationships between redshift and luminosity distance, angular diameter distance and the galaxy number count.

  18. Necessary and sufficient conditions for big bangs, bounces, crunches, rips, sudden singularities, and extremality events

    E-Print Network [OSTI]

    Celine Cattoen; Matt Visser

    2005-08-30

    The physically relevant singularities occurring in FRW cosmologies had traditionally been thought to be limited to the "big bang", and possibly a "big crunch". However, over the last few years, the zoo of cosmological singularities considered in the literature has become considerably more extensive, with "big rips" and "sudden singularities" added to the mix, as well as renewed interest in non-singular cosmological events such as "bounces" and "turnarounds". In this article we present a complete catalogue of such cosmological milestones, both at the kinematical and dynamical level. First, using generalized power series, purely kinematical definitions of these cosmological events are provided in terms of the behaviour of the scale factor a(t). The notion of a "scale-factor singularity'" is defined, and its relation to curvature singularities (polynomial and differential) is explored. Second, dynamical information is extracted by using the Friedmann equations (without assuming even the existence of any equation of state) to place constraints on whether or not the classical energy conditions are satisfied at the cosmological milestones. We use these considerations to derive necessary and sufficient conditions for the existence of cosmological milestones such as bangs, bounces, crunches, rips, sudden singularities, and extremality events. Since the classification is extremely general, the corresponding results are to a high degree model-independent: In particular, we provide a complete characterization of the class of bangs, crunches, and sudden singularities for which the dominant energy condition is satisfied.

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

    SciTech Connect (OSTI)

    Mathews, G. J.; Yamazaki, D.; Kusakabe, M.; Cheoun, M.-K.

    2014-05-02

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

  20. Nucleosynthesis in gamma-ray bursts outflows

    E-Print Network [OSTI]

    M. Lemoine

    2002-06-19

    It is shown that fusion of neutrons and protons to He-4 nuclei occurs in gamma-ray burst outflows in a process similar to big-bang nucleosynthesis in the early Universe. Only the surviving free neutrons can then decouple kinematically from the charged fluid so that the multi-GeV neutrino signal predicted from inelastic nuclear n-p collisions is significantly reduced. It is also argued that a sizeable fraction of ultra-high energy cosmic rays accelerated in gamma-ray bursts should be He-4 nuclei.

  1. "Big Bang'' as a result of first-order phase transition driven by changing scalar curvature in expanding early Universe: "hyperinflation'' scenario

    E-Print Network [OSTI]

    E. A. Pashitskii; V. I. Pentegov

    2015-10-09

    We suggest that the "Big Bang" may be a result of the first-order phase transition driven by changing scalar curvature of the 4D space-time in expanding cold Universe, filled with nonlinear scalar field $\\phi $ and neutral matter with equation of state $p=\

  2. The Big Bang explosion at the start of the Universe was responsible for the production of the light elements hydrogen and helium, along with

    E-Print Network [OSTI]

    Cowan, John

    The Big Bang explosion at the start of the Universe was responsible for the production of the light elements hydrogen and helium, along with some fraction of lithium. All of the other elements in nature Galaxy and throughout the Universe were essentially composed of only hydrogen and helium -- no heavy

  3. "Big Bang'' as a result of first-order phase transition driven by changing scalar curvature in expanding early Universe: "hyperinflation'' scenario

    E-Print Network [OSTI]

    Pashitskii, E A

    2015-01-01

    We suggest that the "Big Bang" may be a result of the first-order phase transition driven by changing scalar curvature of the 4D space-time in expanding cold Universe, filled with nonlinear scalar field $\\phi $ and neutral matter with equation of state $p=\

  4. Optical models of the big bang and non-trivial space-time metrics based on metamaterials

    E-Print Network [OSTI]

    Igor I. Smolyaninov

    2009-08-17

    Optics of metamaterials is shown to provide interesting table top models of many non-trivial space-time metrics. The range of possibilities is broader than the one allowed in classical general relativity. For example, extraordinary waves in indefinite metamaterials experience an effective metric, which is formally equivalent to the "two times physics" model in 2+2 dimensions. An optical analogue of a "big bang" event is presented during which a (2+1) Minkowski space-time is created together with large number of particles populating this space-time. Such metamaterial models enable experimental exploration of the metric phase transitions to and from the Minkowski space-time as a function of temperature and/or light frequency.

  5. Nuclear weak interaction rates in primordial nucleosynthesis

    E-Print Network [OSTI]

    George M. Fuller; Christel J. Smith

    2010-09-01

    We calculate the weak interaction rates of selected light nuclei during the epoch of Big Bang Nucleosynthesis (BBN), and we assess the impact of these rates on nuclear abundance flow histories and on final light element abundance yields. We consider electron and electron antineutrino captures on 3He and 7Be, and the reverse processes of positron capture and electron neutrino capture on 3H and 7Li. We also compute the rates of positron and electron neutrino capture on 6He. We calculate beta and positron decay transitions where appropriate. As expected, the final standard BBN abundance yields are little affected by addition of these weak processes, though there can be slight alterations of nuclear flow histories. However, non-standard BBN scenarios, e.g., those involving out of equilibrium particle decay with energetic final state neutrinos, may be affected by these processes.

  6. Big Bang Nuns

    E-Print Network [OSTI]

    Hacker, Randi

    2013-02-06

    Broadcast Transcript: This is how the world began: not with a bang but with a spinning slap kick. At least, this is what His Holiness Gyalwang Drukpa implied when he brought a group of teen-age Buddhist kung-fu nuns to visit the CERN large hadron...

  7. Big Bang Day : Today

    SciTech Connect (OSTI)

    2009-11-16

    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 )

  8. Big Bang Day : Today

    ScienceCinema (OSTI)

    None

    2011-04-25

    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 )

  9. Neutron injection during primordial nucleosynthesis alleviates the primordial 7Li problem

    E-Print Network [OSTI]

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

    2012-08-02

    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.

  10. Planck is Europe's first mission to study the relic radiation from the Big Bang. Ever since the detection of small fluctuations in the temperature of this radiation, announced in late 1992,

    E-Print Network [OSTI]

    the Nobel Prize in 1918. Planck will map the structure of the Cosmic Microwave Background radiationPlanck Planck is Europe's first mission to study the relic radiation from the Big Bang. Ever since the detection of small fluctuations in the temperature of this radiation, announced in late 1992, astronomers

  11. Constraining spacetime noncommutativity with primordial nucleosynthesis

    SciTech Connect (OSTI)

    Horvat, Raul; Trampetic, Josip

    2009-04-15

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

  12. KADoNiS- The Karlsruhe Astrophysical Database of Nucleosynthesis in Stars

    E-Print Network [OSTI]

    I. Dillmann; M. Heil; F. Käppeler; R. Plag; T. Rauscher; F. -K. Thielemann

    2008-05-30

    The "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars" (KADoNiS) project is an online database for experimental cross sections relevant to the s process and p process. It is available under http://nuclear-astrophysics.fzk.de/kadonis and consists of two parts. Part 1 is an updated sequel to the previous Bao et al. compilations from 1987 and 2000 for (n,$\\gamma$) cross sections relevant to the big bang and s-process nucleosynthesis. The second part will be an experimental p-process database, which is expected to be launched in winter 2005/06. The KADoNiS project started in April 2005, and a first partial update is online since August 2005. In this paper we present a short overview of the first update of the s-process database, as well as an overview of the status of stellar (n,$\\gamma$) cross sections of all 32 p isotopes.

  13. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

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

    2014-09-19

    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.

  14. Nucleosynthesis in barium stars

    E-Print Network [OSTI]

    Trimble, V; Trimble, V

    1984-01-01

    problem of apparent nucleosynthesis in barium stars, thoughSE24 9JF. Astronomy Nucleosynthesis in barium stars fromopportunity to see that nucleosynthesis really is taking

  15. METALLICITY-DEPENDENT GALACTIC ISOTOPIC DECOMPOSITION FOR NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    West, Christopher; Heger, Alexander, E-mail: west0482@umn.edu, E-mail: alexander.heger@monash.edu [Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2013-09-01

    All stellar evolution models for nucleosynthesis require an initial isotopic abundance set to use as a starting point. Generally, our knowledge of isotopic abundances of stars is fairly incomplete except for the Sun. We present a first model for a complete average isotopic decomposition as a function of metallicity. Our model is based on the underlying nuclear astrophysics processes, and is fitted to observational data, rather than traditional forward galactic chemical evolution modeling which integrates stellar yields beginning from big bang nucleosynthesis. We first decompose the isotopic solar abundance pattern into contributions from astrophysical sources. Each contribution is then assumed to scale as a function of metallicity. The resulting total isotopic abundances are summed into elemental abundances and fitted to available halo and disk stellar data to constrain the model's free parameter values. This procedure allows us to use available elemental observational data to reconstruct and constrain both the much needed complete isotopic evolution that is not accessible to current observations, and the underlying astrophysical processes. As an example, our model finds a best fit for Type Ia contributing {approx_equal} 0.7 to the solar Fe abundance, and Type Ia onset occurring at [Fe/H] {approx_equal} -1.1, in agreement with typical values.

  16. Big Bang Day : Physics Rocks

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

  17. Big Bang Day: Engineering Solutions

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

  18. CANWE COME? THE BIG BANG

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    for him to be there, he said, because "all the problems those guys don't solve wind up with us." #12;Today energy? ·What is responsible for ``inflation"? ·What happened at t=0? #12;Physical Law and the Universe

  19. Explosive nucleosynthesis

    E-Print Network [OSTI]

    M. Hernanz

    2001-03-26

    Many radioactive nuclei relevant for gamma-ray astrophysics are synthesized during explosive events, such as classical novae and supernovae. A review of recent results of explosive nucleosynthesis in these scenarios is presented, with a special emphasis on the ensuing gamma-ray emission from individual nova and supernova explosions. The influence of the dynamic properties of the ejecta on the gamma-ray emission features, as well as the still remaining uncertainties in nova and supernova models is also reviewed.

  20. Nucleosynthesis in Thermonuclear Supernovae

    SciTech Connect (OSTI)

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

    2013-01-01

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

  1. OXFORD UNIVERSITY COMPUTING LABORATORY

    E-Print Network [OSTI]

    OXFORD UNIVERSITY COMPUTING LABORATORY The Expressive Power of Binary Submodular Functions Stanislav Zivn´y, David Cohen, Peter Jeavons Computing Laboratory, University of Oxford Rutgers, 22 January LABORATORY Problem Which submodular polynomials can be expressed by (or decomposed into) quadratic submodular

  2. Luu, T; Platter, L 73 NUCLEAR PHYSICS AND RADIATION PHYSICS;...

    Office of Scientific and Technical Information (OSTI)

    constraints from Big Bang nucleosynthesis Bedaque, P; Luu, T; Platter, L 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; DEUTERIUM; FIELD THEORIES; NUCLEAR PHYSICS; NUCLEOSYNTHESIS;...

  3. 4. Nucleosynthesis I. Aretxaga

    E-Print Network [OSTI]

    Aretxaga, Itziar

    4. Nucleosynthesis I. Aretxaga 2014 #12;We have that MR-3 radR-4 There must be a z at which M= rad Taking into account that nucleosynthesis predicts n=0.68 n , then rad=4.2 x 10-5 h-2 1+zeq = 23900mh2 radiation to matter dominated Universe at z~3100 (t~60000 yr): recombination nucleosynthesis #12;Epochs

  4. LHC, le Big Bang en éprouvette

    ScienceCinema (OSTI)

    None

    2011-10-06

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

  5. Big-Bang Cosmology Hitoshi Murayama

    E-Print Network [OSTI]

    Murayama, Hitoshi

    was higher than about 3000K, all atoms (mostly hydrogen and helium) were ionized. · Photons scatter off;Polarization · Compton scattering polarizes the photon in the polarization plane Ei E j - 1 2 dij r E2 µ · Best tested theory of Early Universe · Baryon-to-photon ratio hnB/ng only parameter · Neutron decay

  6. The reconstructed Big Bang from RHIC data

    E-Print Network [OSTI]

    A. Ster; T. Csorgo

    2001-12-04

    The final state of $Au + Au$ collisions at sqrt{s}=130 AGeV at RHIC has been reconstructed within the framework of the Buda-Lund hydro model, by performing a simultaneous fit to preliminary PHENIX and STAR data on two-particle Bose-Einstein correlations and identified single particle spectra. The Hubble constant of the expanding final state of this heavy ion collision is determined to be H = = 0.77 +- 0.09.

  7. A different Big Bang theory: Los Alamos

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve Lithium-Ion Batteries PrintA New SolarAComplex

  8. oxford world's classics PHILOSOPHICAL CRUMBS

    E-Print Network [OSTI]

    Doyle, Robert

    oxford world's classics REPETITION and PHILOSOPHICAL CRUMBS Søren Aabye Kierkegaard (1813:29:34 PM #12;oxford world's classics For over 100 years Oxford World's Classics have brought readers closer to the world's great literature. Now with over 700 titles --from the 4,000-year-old myths of Mesopotamia

  9. Internet Institute University of Oxford

    E-Print Network [OSTI]

    The Oxford Internet Institute University of Oxford #12;A significant proportion of social, economic Science Internet Economics Connectivity, Inclusion and InequalityEducation, Wellbeing and Digital Life Digital Knowledge and Culture #12;The Oxford Internet Institute It's an incredibly exciting time

  10. Neutron-induced nucleosynthesis

    E-Print Network [OSTI]

    H. Oberhummer; H. Herndl; T. Rauscher; H. Beer

    1996-08-20

    Neutron--induced nucleosynthesis plays an important role in astrophysical scenarios like in primordial nucleosynthesis in the early universe, in the s--process occurring in Red Giants, and in the $\\alpha$--rich freeze--out and r--process taking place in supernovae of type II. A review of the three important aspects of neutron--induced nucleosynthesis is given: astrophysical background, experimental methods and theoretical models for determining reaction cross sections and reaction rates at thermonuclear energies. Three specific examples of neutron capture at thermal and thermonuclear energies are discussed in some detail.

  11. Nucleosynthesis and Neutrinos

    SciTech Connect (OSTI)

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

    2011-05-06

    Neutrinos play the critical roles in nucleosynthesis of light-to-heavy mass nuclei in core-collapse supernovae. We study the nucleosynthesis induced by neutrino interactions and find suitable average neutrino temperatures in order to explain the observed solar system abundances of several isotopes {sup 7}Li, {sup 11}B, {sup 138}La and {sup 180}Ta. These isotopes are predominantly synthesized by the supernova {nu}-process. We also study the neutrino oscillation effects on their abundances and propose a method to determine the unknown neutrino oscillation parameters, i.e. {theta}{sub 13} and mass hierarchy.

  12. STEVE RAYNER UNIVERSITY OF OXFORD

    E-Print Network [OSTI]

    STEVE RAYNER UNIVERSITY OF OXFORD James Martin Professor of Science and Civilization School Business School Professorial Fellow, Keble College 64 Banbury Road Oxford OX2 6PG +44 (0)1865 288938 steve.rayner BREAKTHROUGH INSTIUTE Senior Fellow #12;Steve Rayner ­ March 2012 2 CAREER SUMMARY Steve Rayner is James Martin

  13. TITLE AUTHORS SUBJECT SUBJECT RELATED DESCRIPTION PUBLISHER AVAILABILI...

    Office of Scientific and Technical Information (OSTI)

    Quark mass variation constraints from Big Bang nucleosynthesis Bedaque P Luu T Platter L NUCLEAR PHYSICS AND RADIATION PHYSICS DEUTERIUM FIELD THEORIES NUCLEAR PHYSICS...

  14. Explosive Nucleosynthesis: Prospects

    E-Print Network [OSTI]

    David Arnett

    1999-08-16

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

  15. Nucleosynthesis in classical novae

    E-Print Network [OSTI]

    M. Hernanz; J. Jose; A. Coc

    2001-01-19

    A general review of the relevance of classical novae for the chemical evolution of the Galaxy, as well as for Galactic radioactivity is presented. A special emphasis is put on the pioneering work done by Jim Truran in this field of research. The impact of recent developments in nuclear astrophysics on nova nucleosynthesis, together with the prospects for observability of novae radioactivities with the INTEGRAL satellite are discussed.

  16. Supernova neutrinos and nucleosynthesis

    E-Print Network [OSTI]

    G. Martínez-Pinedo; T. Fischer; L. Huther

    2013-09-21

    Observations of metal-poor stars indicate that at least two different nucleosynthesis sites contribute to the production of r-process elements. One site is responsible for the production of light r-process elements Zwinds from core-collapse supernova are the main site for the production of these elements. We explore this possibility by performing nucleosynthesis calculations based on long term Boltzmann neutrino transport simulations. They are based on an Equation of State that reproduces recent constrains on the nuclear symmetry energy. We predict that the early ejecta is neutron-rich with Ye ~ 0.48, it becomes proton rich around 4 s and reaches Ye = 0.586 at 9 s when our simulation stops. The nucleosynthesis in this model produces elements between Zn and Mo, including 92Mo. The elemental abundances are consistent with the observations of the metal-poor star HD 12263. For the elements between Ge and Mo, we produce mainly the neutron-deficient isotopes. This prediction can be confirmed by observations of isotopic abundances in metal-poor stars. No elements heavier than Mo (Z=42) and no heavy r-process elements are produced in our calculations.

  17. Explosive Nucleosynthesis in Hypernovae

    E-Print Network [OSTI]

    Takayoshi Nakamura; Hideyuki Umeda; Koichi Iwamoto; Ken'ichi Nomoto; Masa-aki Hashimoto; W. Raphael Hix; Friedrich-Karl Thielemann

    2001-03-25

    We examine the characteristics of nucleosynthesis in 'hypernovae', i.e., supernovae with very large explosion energies ($ \\gsim 10^{52} $ ergs). We carry out detailed nucleosynthesis calculations for these energetic explosions and compare the yields with those of ordinary core-collapse supernovae. We find that both complete and incomplete Si-burning takes place over more extended, lower density regions, so that the alpha-rich freezeout is enhanced and produces more Ti in comparison with ordinary supernova nucleosynthesis. In addition, oxygen and carbon burning takes place in more extended, lower density regions than in ordinary supernovae. Therefore, the fuel elements O, C, Al are less abundant while a larger amount of Si, S, Ar, and Ca ("Si") are synthesized by oxygen burning; this leads to larger ratios of "Si"/O in the ejecta. Enhancement of the mass ratio between complete and incomplete Si-burning regions in the ejecta may explain the abundance ratios among iron-peak elements in metal-poor stars. Also the enhanced "Si"/O ratio may explain the abundance ratios observed in star burst galaxies. We also discuss other implications of enhanced [Ti/Fe] and [Fe/O] for Galactic chemical evolution and the abundances of low mass black hole binaries.

  18. Galactic cosmic rays and nucleosynthesis

    SciTech Connect (OSTI)

    Kiener, Juergen [CSNSM, CNRS-IN2P3 and Universite Paris-Sud, Bat. 104-108, 91405 Orsay Campus (France)

    2010-03-01

    The nucleosynthesis of the light elements Li, Be and B by galactic cosmic rays is presented. Observations of cosmic rays and the nuclear reactions responsible for Li, Be and B nucleosynthesis are described, followed by some words on propagation. At the end, some open questions concerning galactic cosmic rays are discussed.

  19. Nucleosynthesis results from INTEGRAL

    E-Print Network [OSTI]

    G. Weidenspointner

    2006-01-15

    Since its launch in October 2002, ESA's INTEGRAL observatory has enabled significant advances to be made in the study of Galactic nucleosynthesis. In particular, the imaging Ge spectrometer SPI combines for the first time the diagnostic powers of high resolution gamma-ray line spectroscopy and moderate spatial resolution. This review summarizes the major nucleosynthesis results obtained with INTEGRAL so far. Positron annihilation in our Galaxy is being studied in unprecented detail. SPI observations yield the first sky maps in both the 511 keV annihilation line and the positronium continuum emission, and the most accurate spectrum at 511 keV to date, thereby imposing new constraints on the source(s) of Galactic positrons which still remain(s) unidentified. For the first time, the imprint of Galactic rotation on the centroid and shape of the 1809 keV gamma-ray line due to the decay of 26Al has been seen, confirming the Galactic origin of this emission. SPI also provided the most accurate determination of the gamma-ray line flux due to the decay of 60Fe. The combined results for 26Al and 60Fe have important implications for nucleosynthesis in massive stars, in particular Wolf-Rayet stars. Both IBIS and SPI are searching the Galactic plane for young supernova remnants emitting the gamma-ray lines associated with radioactive 44Ti. None have been found so far, which raises important questions concerning the production of 44Ti in supernovae, the Galactic supernova rate, and the Galaxy's chemical evolution.

  20. Pygmy resonances and nucleosynthesis

    E-Print Network [OSTI]

    Nadia Tsoneva; Horst Lenske

    2014-11-14

    A microscopic theoretical approach based on a self-consistent density functional theory for the nuclear ground state and QRPA formalism extended with multi-phonon degrees of freedom for the nuclear excited states is implemented in investigations of new low-energy modes called pygmy resonances. Advantage of the method is the unified description of low-energy multiphonon excitations, pygmy resonances and core polarization effects. This is found of crucial importance for the understanding of the fine structure of nuclear response functions at low energies. Aspects of the precise knowledge of nuclear response functions around the neutron threshold are discussed in a connection to nucleosynthesis.

  1. Nucleosynthesis in stellar flares

    E-Print Network [OSTI]

    V. Tatischeff; J. -P. Thibaud; I. Ribas

    2008-01-11

    Nuclear interactions of ions accelerated at the surface of flaring stars can produce fresh isotopes in stellar atmospheres. Although this nucleosynthesis is not significant for the chemical evolution of the Galaxy, it can be important for a number of measurements of "anomalously" high 6-Li and 7-Li abundances. We discuss the possible role of stellar flares to explain the recent report of high 6-Li abundances in metal-poor halo stars and the well-established correlation between Li abundance and stellar activity in young open clusters. We then study the possibility of observing directly Li production during flares of nearby and active dwarfs of spectral type M.

  2. New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis

    E-Print Network [OSTI]

    Rauscher, Thomas

    New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis Robert reaction rates needed to study nucleosynthesis in massive stars. Results for the calculated nucleosynthesis( ) © Mg, and their effect on the structure of the star and resultant nucleosynthesis. Both have been

  3. Nucleosynthesis in slowly evolving Cosmologies

    E-Print Network [OSTI]

    Pranav Kumar; Daksh Lohiya

    2008-02-08

    We explore aspects of Cosmological Nucleosynthesis in an FRW universe in which the scale factor evolves linearly with time: $a(t) \\sim t$. A high Lepton number density during the period when significant nucleosynthesis takes place would lead to a dominant screening of the Coulomb potential of colliding nucleii. This would lead to a significant enhancement of nucleosynthesis rates. We demonstrate how adequate amount of $^4He$ and a collataral metallicity, close to the lowest metallicity observed in metal poor Pop II stars and clouds, can be produced with such an evolution.

  4. Neutrinos and Nucleosynthesis in Supernova

    E-Print Network [OSTI]

    U. Solis; J. C. D'Olivo; L. G. Cabral-Rosetti

    2005-11-12

    The type II supernova is considered as a candidate site for the production of heavy elements. The nucleosynthesis occurs in an intense neutrino flux, we calculate the electron fraction in this environment.

  5. Nucleosynthesis In Core Collapse Supernovae

    E-Print Network [OSTI]

    M. Limongi; A. Chieffi

    2006-01-10

    We present the basic properties of the yields of our latest set of presupernova evolution and explosive nucleosynthesis of massive stars in the range between 11 and 120 Msun having solar and zero metallicity.

  6. Neutron Capture Nucleosynthesis in Early Galactic Environments #

    E-Print Network [OSTI]

    Cowan, John

    Neutron Capture Nucleosynthesis in Early Galactic Environments # James W. Truran 1 , John J. Cowan we can extract useful clues to and constraints upon the star formation and nucleosynthesis history that provide the site for s­process nucleosynthesis during the AGB phase of their evolution. We review recent

  7. Nucleosynthesis in AGB Stars Maria Lugaro

    E-Print Network [OSTI]

    Nucleosynthesis in AGB Stars Maria Lugaro A thesis submitted for the degree of Doctor of Philosophy.1 Evolution prior and through the AGB phase . . . . . . . . . . . . . . . 1 1.2 Nucleosynthesis and mixing and models 15 2.1 The Monash Stellar Nucleosynthesis code . . . . . . . . . . . . . . . . . 15 2.1.1 Nuclear

  8. Nucleosynthesis in AGB Stars John Lattanzio

    E-Print Network [OSTI]

    Lattanzio, John

    Nucleosynthesis in AGB Stars John Lattanzio Dept of Mathematics and Statistics, Monash University of the nucleosynthesis occurring in AGB stars. We the summarise some new calculations of intermediate mass stars which include all thermal pulses until the star is about to leave the AGB, as well as a detailed nucleosynthesis

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

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

    Harry Potter, Oxford and Nuclear Energy Harry Potter, Oxford and Nuclear Energy July 16, 2012 - 1:30pm Addthis Assistant Secretary Dr. Peter Lyons meets with students on the Oxford...

  10. Modified GR and Helium Nucleosynthesis

    E-Print Network [OSTI]

    A. S. Al-Rawaf

    2006-06-12

    We show that a previously proposed cosmological model based on general relativity with non vanishing divergence for the energy-momentum tensor is consistent with the observed values for the nucleosynthesis of helium for some values of the arbitrary parameter $\\alpha$ presented in this model. Further more values of $\\alpha$ can be accommodated if we adopt the Randall-Sundrum single brane model.

  11. Nucleosynthesis in Type II Supernovae

    E-Print Network [OSTI]

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

    1997-06-03

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

  12. Top Tips for Accessing Oxford's Information Resources

    E-Print Network [OSTI]

    Oxford, University of

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

  13. Top Tips for Accessing Oxford's Information Resources

    E-Print Network [OSTI]

    Oxford, University of

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

  14. Oxford Solar | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver CoreOxford Solar Jump to:

  15. Gravity waves generated by sounds from big bang phase transitions

    E-Print Network [OSTI]

    Tigran Kalaydzhyan; Edward Shuryak

    2015-04-03

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

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

    E-Print Network [OSTI]

    Geoffrey F. Chew

    2015-07-09

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

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

  18. Supercomputing: A Toolbox to Simulate the Big Bang and Beyond...

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

    of the Energy Department's investments in supercomputers and specialized high-performance computing codes. The team is developing an open platform with a web-based front end...

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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 .......

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

    ScienceCinema (OSTI)

    None

    2011-04-25

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

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

    SciTech Connect (OSTI)

    None

    2009-10-07

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

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

    SciTech Connect (OSTI)

    None

    2009-10-06

    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 .......

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

    ScienceCinema (OSTI)

    None

    2011-04-25

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

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

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

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

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

  8. Stable Emergent Universe -- A Creation without Big-Bang

    E-Print Network [OSTI]

    Guendelman, Eduardo; Labrana, Pedro; Nissimov, Emil; Pacheva, Svetlana

    2015-01-01

    Based on an earlier introduced new class of generalized gravity-matter models defined in terms of two independent non-Riemannian volume forms (alternative generally covariant integration measure densities) on the space-time manifold, we derive an effective "Einstein-frame" theory featuring the following remarkable properties: (i) We obtain effective potential for the cosmological scalar field possessing two infinitely large flat regions which allows for a unified description of both early universe inflation as well as of present dark energy epoch; (ii) For a specific parameter range the model possesses a non-singular stable "emergent universe" solution which describes an initial phase of evolution that precedes the inflationary phase.

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAudits & InspectionsBeryllium and ChronicBestBeyond theBid-List

  10. COLLOQUIUM: Seeing the Big Bang More Clearly: The Evolution of

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAudits &BradburyMay 1, 2013, 4:15pm ColloquiaPhysicsPlasma

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.TheoryTuesday, August 10, 20102016 News BelowAsked toUSC-Aiken,AU T H O R

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking WithTelecentricNCubic Feet)CompletesResearch Started thetoWhat

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse Bergkamp Graduate student Subtask 4 project:Jimmyabout/jobs/John BacikJohn

  14. HydrodynamicallyBased Overshoot Treatment and Nucleosynthesis

    E-Print Network [OSTI]

    Hydrodynamically­Based Overshoot Treatment and Nucleosynthesis in AGB Stars F. Herwig 1 , T. Bl dominated by 12 C. This leads to the nucleosynthesis of 13 C via 12 C(p; fl) 13 N(fi; + š) 13 C and is prob­ ably the major source of neutrons ( 13 C(ff; n) 16 O) for subsequent s­process nucleosynthesis. We

  15. Nucleosynthesis in Early Neutrino Driven Winds

    E-Print Network [OSTI]

    R. D. Hoffman; J. L. Fisker; J. Pruet; S. E. Woosley; H. -T. Janka; R. Buras

    2008-01-11

    Nucleosynthesis in early neutrino winds is investigated. Presented is a brief overview of two recent problems of supernova nucleosynthesis. In the first part we investigate the effect of nuclear parameters on the synthesis of Mo92 and Mo94. Based on recent experimental results, we find that the proton rich winds of the model investigated here can not be the source of solar Mo92 and Mo94. In the second part we investigate the nucleosynthesis from neutron rich bubbles and show that they do not contribute to the overall nucleosynthesis.

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

    E-Print Network [OSTI]

    Latham A. Boyle; Alessandra Buonanno

    2007-08-18

    We derive a general master equation relating the gravitational-wave observables r and Omega_gw(f). Here r is the tensor-to-scalar ratio, constrained by cosmic-microwave-background (CMB) experiments; and Omega_gw(f) is the energy spectrum of primordial gravitational-waves, constrained e.g. by pulsar-timing measurements, laser-interferometer experiments, and Big Bang Nucleosynthesis (BBN). Differentiating the master equation yields a new expression for the tilt d(ln Omega_gw(f))/d(ln f). The relationship between r and Omega_gw(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_hat(f) and nt_hat(f), where nt_hat(f) is a certain logarithmic average over nt(k) (the primordial tensor spectral index); and w_hat(f) is a certain logarithmic average over w_tilde(a) (the effective equation-of-state in the early universe, after horizon re-entry). Here the effective equation-of-state parameter w_tilde(a) is a combination of the ordinary equation-of-state parameter w(a) and the bulk viscosity zeta(a). Thus, by comparing constraints on r and Omega_gw(f), one can obtain (remarkably tight) constraints in the [w_hat(f), nt_hat(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 BBN. Finally, although most of our analysis does not assume inflation, we point out that if CMB experiments detect a non-zero value for r, then we will immediately obtain (as a free by-product) a new upper bound w_hat < 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 BBN.

  17. University of Oxford Gender Equality Scheme

    E-Print Network [OSTI]

    Wallace, Mark

    is championing an application for an Athena SWAN award at the same time as the University is seeking renewal of gender equality in Oxford remain models to us all. Dr Sally Mapstone Pro-Vice Chancellor (Personnel

  18. Nuclear Reactions For Nucleosynthesis Beyond Fe

    E-Print Network [OSTI]

    Rauscher, T

    2015-01-01

    Many more nuclear transitions have to be known in the determination of stellar reactivities for trans-iron nucleosynthesis than for reactions of light nuclei. This requires different theoretical and experimental approaches. Some of the issues specific for trans-iron nucleosynthesis are discussed.

  19. Nuclear Reactions For Nucleosynthesis Beyond Fe

    E-Print Network [OSTI]

    T. Rauscher

    2015-08-26

    Many more nuclear transitions have to be known in the determination of stellar reactivities for trans-iron nucleosynthesis than for reactions of light nuclei. This requires different theoretical and experimental approaches. Some of the issues specific for trans-iron nucleosynthesis are discussed.

  20. The Oxford Programme on the Changing Character of War

    E-Print Network [OSTI]

    Oxford, University of

    The Oxford Programme on the Changing Character of War Trinity Term 2015 Lunchtime Discussions on the Changing Character of War Seminars are at 1.00pm, Seminar Room G, Manor Road Building, Oxford A light sandwich lunch is served at 12.50pm. All are welcome. Tuesday 28th April Sir Ivor Roberts (Oxford) War

  1. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

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

    2015-01-01

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

  2. Nucleosynthesis in O-Ne-Mg Supernovae

    E-Print Network [OSTI]

    R. D. Hoffman; B. Muller; H. -T. Janka

    2007-12-27

    We have studied detailed nucleosynthesis in the shocked surface layers of an Oxygen-Neon-Magnesium core collapse supernova with an eye to determining if 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.

  3. Proton-rich nucleosynthesis and nuclear physics

    SciTech Connect (OSTI)

    Rauscher, T.; Froehlich, C. [Dept. of Physics, University of Basel, 4056 Basel (Switzerland); Dept. of Physics, NCSU, Raleigh, NC 27695 (United States)

    2012-11-12

    Although the detailed conditions for explosive nucleosynthesis are derived from astrophysical modeling, nuclear physics determines fundamental patterns in abundance yields, not only for equilibrium processes. Focussing on the {nu}p- and the {gamma}-process, general nucleosynthesis features within the range of astrophysical models, but (mostly) independent of details in the modelling, are presented. Remaining uncertainties due to uncertain Q-values and reaction rates are discussed.

  4. Nucleosynthesis in O-Ne-Mg Supernovae

    SciTech Connect (OSTI)

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

    2007-12-18

    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.

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

    E-Print Network [OSTI]

    Mojzsis, Stephen J.

    1999-01-01

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

  6. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    abundances of light elements created of a variation of the quark masses at the time of Big Bang nucleosynthesis (BBN). In order to navigate through the particle and nuclear...

  7. Outstanding problems in nuclear astrophysics: recent progress at TRIUMF

    SciTech Connect (OSTI)

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

    2014-04-15

    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.

  8. UNIVERSITY OF OXFORD DEPARTMENT OF STATISTICS

    E-Print Network [OSTI]

    Oxford, University of

    UNIVERSITY OF OXFORD DEPARTMENT OF STATISTICS MSc AND DIPLOMA IN APPLIED STATISTICS 2014. Sources of advice and help 33 5. Departmental Facilities 35 #12;2 MSc/ DIPLOMA IN APPLIED STATISTICS 2014/2015 We welcome you to the Department of Statistics and our MSc programme in Applied Statistics

  9. Rothermere American Institute America's Home at Oxford

    E-Print Network [OSTI]

    Oxford, University of

    its commitment to world-class research on the United States. Further financial support is essentialRothermere American Institute America's Home at Oxford Annual Report 2011-12 Director's Review will allow future generations of scholars, students and members of the public to understand better the United

  10. Lithium-Beryllium-Boron : Origin and Evolution

    E-Print Network [OSTI]

    Elisabeth Vangioni-Flam; Michel Casse; Jean Audouze

    1999-07-13

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

  11. Protecting rainforest realism: James Ladyman, Don Ross: Everything must go: metaphysics naturalized, Oxford: Oxford University Press, 2007, pp. 368 £49.00 HB

    E-Print Network [OSTI]

    Kyle Stanford, P.; Humphreys, Paul; Hawley, Katherine; Ladyman, James; Ross, Don

    2010-01-01

    and modality. Cambridge: Cambridge University Press.University of Minnesota Press. Lewis, David. 1986.Oxford: Oxford University Press. Lewis, David. 1994. Humean

  12. Supernova neutrinos and explosive nucleosynthesis

    SciTech Connect (OSTI)

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

    2014-05-09

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

  13. Nucleosynthesis in Type Ia Supernovae

    E-Print Network [OSTI]

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

    1997-06-03

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

  14. Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination

    E-Print Network [OSTI]

    Hu, Wayne

    Lecture Notes on CMB Theory: From Nucleosynthesis to Recombination by Wayne Hu arXiv:0802.3688v1[astro-ph]25Feb2008 #12;Contents CMB Theory from Nucleosynthesis to Recombination page 1 1 Introduction 1 2 Brief Thermal History 1 2.1 Nucleosynthesis and Prediction of the CMB 1 2.2 Thermalization

  15. Abundance Ratio Trends and Nucleosynthesis in Elliptical Galaxies and Spheroids

    E-Print Network [OSTI]

    Worthey, Guy

    Abundance Ratio Trends and Nucleosynthesis in Elliptical Galaxies and Spheroids Guy Worthey 1, nucleosynthesis, abundances --- galaxies: abundances --- galaxies: elliptical and lenticular, cD --- galaxies of the discussion to other elements in section 3. The fourth section discusses nucleosynthesis and possible hints

  16. Nucleosynthesis and the Chemical Evolution of the Universe

    E-Print Network [OSTI]

    Liske, Jochen

    AS2001 Nucleosynthesis and the Chemical Evolution of the Universe Tutorial 3 ­ Answers Question 1. Primordial nucleosynthesis ­ neutrons and protons get together to form the light nuclei D, 3 He, 4 He and 7 instability. Stellar nucleosynthesis ­ all other elements are synthesized inside stars or during supernova

  17. Deuterium Nucleosynthesis in AGN: Is D Cosmological? D. A. Lubowicha

    E-Print Network [OSTI]

    Millar, Tom

    Deuterium Nucleosynthesis in AGN: Is D Cosmological? D. A. Lubowicha , N. Kunob , H. Robertsc , T or cosmic-ray luminosity > 1042 erg/s. If jet-cloud nucleosynthesis produces significant amounts of D on the temperature and baryonic density during the epoch of nucleosynthesis (first 1000 seconds). Thus any

  18. SUPERNOVA NUCLEOSYNTHESIS AS A TOOL TO ANALYZE THE EXPLOSION MECHANISM

    E-Print Network [OSTI]

    Rauscher, Thomas

    SUPERNOVA NUCLEOSYNTHESIS AS A TOOL TO ANALYZE THE EXPLOSION MECHANISM F.­K. Thielemann 1;4 , F for the explosion and ejection of matter. This affects the nucleosynthesis products via two main uncertainties, (i energy responsible for explosive nucleosynthesis. Thus, observations can constrain these quantities. Type

  19. The connection between mass loss and nucleosynthesis

    E-Print Network [OSTI]

    Jacco Th. van Loon

    2008-01-03

    I discuss the relationship between mass loss and nucleosynthesis on the Asymptotic Giant Branch (AGB). Because of thermal pulses and possibly other mixing processes, products of nucleosynthesis can be brought to the surface of AGB stars, increasingly so as the star becomes more luminous, cooler, and unstable against pulsation of its tenuous mantle. As a result, mass loss is at its most extreme when dredge-up is too. As the high rate of mass loss truncates AGB evolution, it determines the enrichment of interstellar space with the AGB nucleosynthesis products. The changing composition of the stellar atmosphere also affects the mass-loss process, most obviously in the formation of dust grains - which play an important role in driving the wind of AGB stars.

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver CoreOxford Solar

  1. Nucleosynthesis in intermediate mass AGB stars

    E-Print Network [OSTI]

    John Lattanzio; Corinne Charbonnel; Manuel Forestini

    1999-12-15

    We present a summary of the main sites for nucleosynthesis in intermediate mass Asymptotic Giant Branch (AGB) stars. We then discuss some detailed evolutionary models and how these have been used to create a synthetic evolution code which calculates the nucleosynthesis very rapidly, enabling us to investigate changes in some uncertain parameters in AGB evolution, such as mass-loss and dredge-up. We then present results for C, C/O, Mg and Al. We also discuss the changes due to the recent NACRE compilation of reaction rates.

  2. NUCLEAR ASPECTS OF STELLAR AND EXPLOSIVE NUCLEOSYNTHESIS

    E-Print Network [OSTI]

    Rauscher, Thomas

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

  3. University of Oxford WELLCOME UNIT FOR THE HISTORY OF MEDICINE

    E-Print Network [OSTI]

    Wallace, Mark

    University of Oxford WELLCOME UNIT FOR THE HISTORY OF MEDICINE 45-47 BANBURY ROAD, OXFORD, OX2 6PE Banbury Road on Mondays at 2.15pm Coffee will be available from 2.00pm `Medicine, Leisure and the Arts' 1 Smith elise.smith@wuhmo.ox.ac.uk Wellcome Unit for the History of Medicine Details of all Wellcome Unit

  4. Oxford Undergraduate: Year One (1960-1)

    E-Print Network [OSTI]

    Macfarlane, Alan

    2015-06-16

    -grandfather’s brother John Rhodes James also went to that College. A number of my Jones ancestors went to Oxford, two brothers going to Oriel and and another to Magdalen, while their other brother went to University College London. Two of my Stirling ancestors... background from which I had come. On my mother’s side there were lawyers, soldiers, doctors, school 4 and university teachers, diplomats, naturalists, clergymen and earlier on plantation owners in Jamaica. On my father’s side there were engineers...

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver CoreOxford Solar Jump

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver CoreOxford Solar JumpMichigan:

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver CoreOxford SolarOhio: Energy

  8. Oxford Catalysts Group plc | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsourceII JumpQuarterly Smart Grid DataInformationOpenOsmosisWesternCorningOxford

  9. Nucleosynthesis in asymptotic giant branch stars

    SciTech Connect (OSTI)

    El Eid, Mounib F., E-mail: meid@aub.edu.lb [American University of Beirut, Department of Physics, P.O. Box 11-0236, Riad El-Solh, Beirut (Lebanon)

    2014-05-09

    The nucleosynthesis in asymptotic giant branch stars (briefly: AGB)is a challenging and fascinating subject in the theory of stellar evolution and important for observations as well. This is because about of half the heavy elements beyond iron are synthesized during thermal pulsation phases of these stars. Furthermore, the understanding of the production of the heavy elements and some light elements like carbon and fluorine represent a powerful tool to get more insight into the internal structure of these stars. The diversity of nuclear processing during the AGB phases may also motivate experimental activities in measuring important nuclear reactions. In this contribution, we emphasize several interesting feature of the nucleosynthesis in AGB stars which still needs further elaboration especially from theoretical point of view.

  10. Magic ultramagnetized nuclei in explosive nucleosynthesis

    SciTech Connect (OSTI)

    Kondratyev, V. N., E-mail: vkondra@univ.kiev.ua [Ukraine JINR, Taras Shevchenko National University Kiev (Russian Federation)

    2012-11-15

    Direct evidence of the presence of {sup 44}Ti and content of the isotope in the supernova remnant Cassiopeia A are obtained from the analysis of gamma-ray spectrum of the remnant. A significant excess of observational {sup 44}Ti volume on predictions of supernova models can be explained as the magnetization effect in the process of explosive nucleosynthesis. The formation of chemical elements is considered accounting for superstrong magnetic fields predicted for supernovae and neutron stars. Using the arguments of nuclear statistical equilibrium, a significant effect of magnetic field on the nuclear shell energy is demonstrated. The magnetic shift of the most tightly 'bound' nuclei from the transition metals of iron series to titanium leads to an exponential increase in the portion of {sup 44}Ti and, accordingly to a significant excess of the yield of these products of nucleosynthesis.

  11. Nuclear quests for supernova dynamics and nucleosynthesis

    SciTech Connect (OSTI)

    Langanke, K. [GSI Helmholtzzentrum fuer Schwerionenstreuung, Darmstadt, Germany, Institute fuer Kernphysik, Technical University of Darmstadt, Germany and Frankfurt Institute for Advanced Studies, Frankfurt (Germany); Martinez-Pinedo, G. [GSI Helmholtzzentrum fuer Schwerionenstreuung, Darmstadt (Germany)

    2011-10-28

    Nuclear physics plays a crucial role in various aspects of core collapse supernovae. The collapse dynamics is strongly influenced by electron captures. Using modern many-body theory improved capture rates have been derived recently with the important result that the process is dominated by capture on nuclei until neutrino trapping is achieved. Following the core bounce the ejected matter is the site of interesting nucleosynthesis. The early ejecta are proton-rich and give rise to the recently discovered {nu}p-process. Later ejecta might be neutron-rich and can be one site of the r-process. The manuscript discusses recent progress in describing nuclear input relevant for the supernova dynamics and nucleosynthesis.

  12. Modeling The Nucleosynthesis Of Massive Stars

    E-Print Network [OSTI]

    T. Rauscher

    2003-09-09

    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.

  13. Primordial nucleosynthesis in higher dimensional cosmology

    E-Print Network [OSTI]

    S. Chatterjee

    2009-11-13

    We investigate nucleosynthesis and element formation in the early universe in the framework of higher dimensional cosmology. For this purpose we utilize a previous solution of the present author, which may be termed as the generalized Friedmann-Robertson-Walker model. We find that temperature decays less rapidly in higher dimensional cosmology, which we believe may have nontrivial consequences \\emph{vis-a-vis} primordial physics.

  14. c-Ray lenses taking a deeper look at sites of nucleosynthesis Cornelia B. Wunderer

    E-Print Network [OSTI]

    California at Berkeley, University of

    c-Ray lenses ­ taking a deeper look at sites of nucleosynthesis Cornelia B. Wunderer Space Sciences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617 5. Using lenses to study nucleosynthesis of nucleosynthesis, namely massive stars, novae, and superno

  15. Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars

    SciTech Connect (OSTI)

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

    2011-10-28

    We investigate the heavy-element nucleosynthesis of a massive star whose mass in the main sequence stage is M{sub ms} = 70 M{sub {center_dot}}. Detailed calculations of the nucleosynthesis are performed during the hydrostatic stellar evolution until the core composed of iron-group nuclei begins to collapse. As a supernova explosion model, a collapsar model is constructed whose jets are driven by magnetohydrodynamical effects of a differentially rotating core. The heavy-element nucleosynthesis inside the jet of a collapsar model is followed along the trajectories of stream lines of the jet. We combine the results of both hydrostatic and heavy-element nucleosyntheses to compare with the solar abundances. We find that neutron-rich elements of 70140.

  16. Nucleosynthesis Basics and Applications to Supernovae

    E-Print Network [OSTI]

    F. -K. Thielemann; T. Rauscher; C. Freiburghaus; K. Nomoto; M. Hashimoto; B. Pfeiffer; K. -L. Kratz

    1998-02-06

    This review concentrates on nucleosynthesis processes in general and their applications to massive stars and supernovae. A brief initial introduction is given to the physics in astrophysical plasmas which governs composition changes. We present the basic equations for thermonuclear reaction rates and nuclear reaction networks. The required nuclear physics input for reaction rates is discussed, i.e. cross sections for nuclear reactions, photodisintegrations, electron and positron captures, neutrino captures, inelastic neutrino scattering, and beta-decay half-lives. We examine especially the present state of uncertainties in predicting thermonuclear reaction rates, while the status of experiments is discussed by others in this volume (see M. Wiescher). It follows a brief review of hydrostatic burning stages in stellar evolution before discussing the fate of massive stars, i.e. the nucleosynthesis in type II supernova explosions (SNe II). Except for SNe Ia, which are explained by exploding white dwarfs in binary stellar systems (which will not be discussed here), all other supernova types seem to be linked to the gravitational collapse of massive stars (M$>$8M$_\\odot$) at the end of their hydrostatic evolution. SN1987A, the first type II supernova for which the progenitor star was known, is used as an example for nucleosynthesis calculations. Finally, we discuss the production of heavy elements in the r-process up to Th and U and its possible connection to supernovae.

  17. Bayesian Epistemology, by Luc Bovens and Stephan Hartmann, Oxford: Oxford University Press, 2003, Pp. ix + 159. H/b 37.50. P/b 16.99.

    E-Print Network [OSTI]

    Fitelson, Branden

    Bayesian Epistemology, by Luc Bovens and Stephan Hartmann, Oxford: Oxford University Press, 2003 chapters, Bovens and Hartmann (B&H) engage in a very lucid and penetrating discussion of the notion

  18. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Wallace, Mark

    OxCORT Oxford Colleges On-line Reports for Tutorials Tutorial Office Role Version 4.4 BSP Training Overview of Tutorial reports.................................................................11 Overview of Revision Class reports.....................................................12 Overview of payments

  19. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Wallace, Mark

    OxCORT Oxford Colleges On-line Reports for Tutorials Organising or Personal Tutor Role Version 4 of Tutorial reports...................................................................8 Overview of Revision Class reports.......................................................8 Overview of payments

  20. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Wallace, Mark

    OxCORT Oxford Colleges On-line Reports for Tutorials Senior Tutor Role Version 4.4 BSP Training of Tutorial reports...................................................................8 Overview of Revision Class reports.......................................................8 Overview of payments

  1. Oxford Colleges On-line Reports for Tutorials

    E-Print Network [OSTI]

    Wallace, Mark

    OxCORT Oxford Colleges On-line Reports for Tutorials Tutor Role Version 4.5 BSP Training Team Overview of Tutorial reports...................................................................8 Overview of Revision Class reports.......................................................8 Report states

  2. Oxford Journals Online Oxford Journals Online is a multi-disciplinary e-journal collection that provides full-text access to almost 200 Library-

    E-Print Network [OSTI]

    Po, Lai-Man

    1 Oxford Journals Online Oxford Journals Online is a multi-disciplinary e-journal collection that provides full-text access to almost 200 Library- subscribed journals published by Oxford University Press. 1. At the Library Homepage (http://www.cityu.edu.hk/lib/), select E-Resources. 2. Select E-Journals

  3. Planetary nebulae, tracers of stellar nucleosynthesis

    E-Print Network [OSTI]

    Grazyna Stasinska

    2007-08-31

    We review the information that planetary nebulae and their immediate progenitors, the post-AGB objects, can provide to probe the nucleosynthesis and mixing in low and intermediate mass stars. We emphasize new approaches based on high signal-to-noise spectroscopy of planetary nebulae and of their central stars. We mention some of the problems still to overcome. We emphasize that, as found by several authors, planetary nebulae in low metallicity environments cannot be used to probe the oxygen abundance in the interstellar medium out of which their progenitors were formed, because of abundance modification during stellar evolution.

  4. Nucleosynthesis: a field with still many open nuclear physics questions

    SciTech Connect (OSTI)

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

    2010-06-01

    Stellar nucleosynthesis is a vastly interdisciplinary field. There is a large number of different problems invoked calling for a variety of different and complementary research fields. Impressive progress has been made for the last decades in the various fields related to nucleosynthesis, especially in experimental and theoretical nuclear physics, as well as in ground-based or space astronomical observations and astrophysical modellings. In spite of that success, major problems and puzzles remain. The three major nucleosynthesis processes called for to explain the origin of the elements heavier than iron are described and the major pending questions discussed. As far as nuclear physics is concerned, good quality nuclear data is known to be a necessary condition for a reliable modelling of stellar nucleosynthesis. Through some specific examples, the need for further theoretical or experimental developments is also critically discussed in view of their impact on nucleosynthesis predictions.

  5. Study of the beta delayed particle emission from 48Mn and its relevance for explosive nucleosynthesis

    E-Print Network [OSTI]

    Martel, I

    2015-01-01

    Study of the beta delayed particle emission from 48Mn and its relevance for explosive nucleosynthesis

  6. Neutrino Astrophysics

    E-Print Network [OSTI]

    W. C. Haxton

    2008-08-05

    I review the current status of neutrino astrophysics, including solar neutrinos; atmospheric neutrinos; neutrino mass and oscillations; supernova neutrinos; neutrino nucleosynthesis (Big Bang nucleosynthesis, the neutrino process, the r-process); neutrino cooling and red giants; and high energy neutrino astronomy.

  7. Neutrino Nucleosynthesis of radioactive nuclei in supernovae

    E-Print Network [OSTI]

    A. Sieverding; L. Huther; K. Langanke; G. Martínez-Pinedo; A. Heger

    2015-05-05

    We study the neutrino-induced production of nuclides in explosive supernova nucleosynthesis for progenitor stars with solar metallicity and initial main sequence masses between 15 M$_\\odot$ and 40 M$_\\odot$. We improve previous investigations i) by using a global set of partial differential cross sections for neutrino-induced charged- and neutral-current reactions on nuclei with charge numbers $Z nuclides $^{22}$Na and $^{26}$Al. Both nuclei are prime candidates for gamma-ray astronomy. Other prime targets, $^{44}$Ti and $^{60}$Fe, however, are insignificantly produced by neutrino-induced reactions. We also find a large increase in the production of the long-lived nuclei $^{92}$Nb and $^{98}$Tc due to charged-current neutrino capture.

  8. Electron capture cross sections for stellar nucleosynthesis

    E-Print Network [OSTI]

    P. G. Giannaka; T. S. Kosmas

    2015-02-25

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

  9. Nucleosynthesis and the rp-process

    SciTech Connect (OSTI)

    Nabi, Jameel-Un [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Swabi, Khyber Pakhtunkhwa (Pakistan)

    2012-11-20

    Production of elements heavier than iron, their abundance and cite of production remain an active field of research to-date. In this paper I would present a brief review of the nucleosynthesis process and then focus further on the proton capture processes with particular emphasis on the nuclear physics aspects of the rp-process. The present calculation clearly shows that the electron capture rates on waiting point nuclei are at least of similar magnitude as the competing positron decay rates under rp-process conditions. The study strongly suggests that electron capture rates form an integral part of weak-interaction mediated rates under rp-process conditions and should not be neglected in nuclear reaction network calculations as done in past.

  10. R-process Nucleosynthesis in Supernova Explosion

    SciTech Connect (OSTI)

    Saruwatari, M.; Hashimoto, M. [Department of Physics, School of Sciences, Kyushu University, Fukuoka 812-8581 (Japan); Kotake, K. [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Yamada, S. [Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjyuku, Tokyo, 169-8555 (Japan)

    2011-10-28

    We investigate the possibility of the r-process during the magnetohydrodynamical (MHD) explosion of supernova in a massive star of 13 M{sub {center_dot}} with the effects of neutrinos included. Contrary to the case of the spherical explosion, jet-like explosion due to the combined effects of rotation and magnetic field lowers the electron fraction significantly inside the layers. We find that the ejected material of low electron fraction responsible for the r-process comes out from the inner deep region of the core that is made up of iron-group nuclei. This leads to the production of the second to third peak in the solar r-process elements. We suggest that there are some variations in the r-process nucleosynthesis according to the initial conditions of rotational and magnetic fields.

  11. Beta decay rates for nuclei with 115 nucleosynthesis

    E-Print Network [OSTI]

    Kamales Kar; Soumya Chakravarti; V. R. Manfredi

    2006-03-19

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

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

    E-Print Network [OSTI]

    Houlsby, Guy T.

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

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

    E-Print Network [OSTI]

    for the Environment South Parks Road Oxford OX1 3QY www.eci.ox.ac.uk www.ukerc.ac.uk #12;UK Energy Research Centre 2 1 than carbon taxes or upstream measures would, but there is little evidence to substantiate

  14. University of Oxford Transgender Policy Purpose of this policy

    E-Print Network [OSTI]

    Henderson, Gideon

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

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

    E-Print Network [OSTI]

    Henderson, Gideon

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

  16. University of Oxford Energy Toolkit2011/12

    E-Print Network [OSTI]

    Melham, Tom

    's Carbon Management Strategy go to: www.admin.ox.ac.uk/estates/environment/energy/ carbonmanagementstrategyUniversity of Oxford Energy Toolkit2011/12 www.admin.ox.ac.uk/estates/environment/energy emissions through our carbon management strategy. It is now even more important that the University acts

  17. Neutrino Capture and r-Process Nucleosynthesis

    E-Print Network [OSTI]

    Bradley S. Meyer; Gail C. McLaughlin; George M. Fuller

    1998-09-18

    We explore neutrino capture during r-process nucleosynthesis in neutrino-driven ejecta from nascent neutron stars. We focus on the interplay between charged-current weak interactions and element synthesis, and we delineate the important role of equilibrium nuclear dynamics. During the period of coexistence of free nucleons and light and/or heavy nuclei, electron neutrino capture inhibits the r-process. At all stages, capture on free neutrons has a larger impact than capture on nuclei. However, neutrino capture on heavey nuclei by itself, if it is very strong, is also detrimental to the r-process until large nuclear equilibrium clusters break down and the classical neutron-capture phase of the r-process begins. The sensitivity of the r-process to neutrino irradiation means that neutrino-capture effects can strongly constrain the r-process site, neutrino physics, or both. These results apply also to r-process scenarios other than neutrino-heated winds.

  18. Abundances for p-process nucleosynthesis

    SciTech Connect (OSTI)

    De Laeter, John R.

    2008-04-15

    An important constraint in developing models of p-process nucleosynthesis is that the abundances of many of the p-process nuclides are not well known. A recent review of the p-process has identified six p-process nuclides that are of particular significance to p-process theorists [M. Arnould and S. Goriely, Phys. Rep. 384, 1 (2003)]. These nuclides are {sup 92,94}Mo, {sup 96,98}Ru, {sup 138}La, and {sup 180}Ta{sup m}. The absence of accurate abundances for these isotopes is due to the fact that the isotopic composition of the elements concerned have not been corrected for isotope fractionation induced by the thermal ionization mass spectrometric instruments used to measure them. To remedy this deficiency, a VG 354 mass spectrometer was calibrated using gravimetric mixtures of enriched isotopes to enable the absolute isotopic compositions of these elements to be obtained. Although the isotopic abundances of {sup 92,94}Mo, {sup 138}La, and {sup 180}Ta{sup m} have previously been reported, the absolute abundances of {sup 96,98}Ru are reported for the first time in this article, with a significant reduction in the magnitude of the values as compared to existing abundances.

  19. Challenges in explosive nucleosynthesis of heavy elements

    SciTech Connect (OSTI)

    Pinedo, Gabriel Martinez; Fischer, T.; Lohs, A.; Huther, L.

    2012-10-20

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

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

    SciTech Connect (OSTI)

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

    1990-05-07

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

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

    ScienceCinema (OSTI)

    None

    2011-04-25

    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.

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

    E-Print Network [OSTI]

    Timashev, Serge F

    2008-01-01

    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.

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

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

    doctoral degree (2000) and bachelor's degree (1996) in physics from the University of Pisa, Italy. Cirigliano was named a Fellow of the American Physical Society in 2012 and...

  4. Water from Heaven: The Story of Water from the Big Bang to the

    E-Print Network [OSTI]

    that is understandable to the educated lay reader. Kandel displays impressive didactic powers in making intri- cate cycle, the recurrent ice ages, cloud formations and precipitation, the inter-tropical convergence zone no distinction between the processes of evaporation from the soil (which is a loss) and transpiration by plants

  5. O que aconteceu uma fraco de segundo depois do Big Bang

    E-Print Network [OSTI]

    Instituto de Sistemas e Robotica

    houve uma grande explosão que criou matéria, espa- ço e tempo e depois um esticão que numa fracção de anos de observações onde parece haver sinais incontornáveis desse fenómeno em deformações do espa- ço

  6. Jetting into the Moments after the Big Bang | U.S. DOE Office...

    Office of Science (SC) Website

    shining brightly at temperatures more than 100,000 times hotter than the center of the Sun. To explore the properties of this plasma of quarks and gluons as it expands and cools,...

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

    E-Print Network [OSTI]

    Serge F. Timashev

    2008-04-17

    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.

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

    E-Print Network [OSTI]

    PLAYING GOD WITH BIOLOGY DRONES ON TEST Q&A The revolution behind glowing trees and DNA computers Plane vs

  9. Fusion in first few minutes after Big Bang form lightest elements

    E-Print Network [OSTI]

    Shirley, Yancy

    in the dying stages of a stars life. #12;Example : How do we get Carbon ? #12;Temperature Luminosity Stars's life expectancy: 10 billion years Life expectancy of 10 MSun star: 10 times as much fuel, uses it 104, Si, etc. up to Fe. #12;Evolution off Main Sequence (Red Giant Phase) #12;Review: Where does Carbon

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura| National2.11DESERTWaterSharingBeyondBang or Big

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGEMissionStressMoveMuncriefB O N NStaffDay February 13

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room News PublicationsAudits &BradburyMay 1, 2013, 4:15pm Colloquia MBGLabPrincetonOctober

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| Department ofStephen P riceawards | PrincetonPPPL'sorigin of the

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal GasAdministration Medal01TechnicalScientific andScientific andofofEnergy,Lake,and

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

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematicsEnergyInterested Parties -Department ofDepartmentNaturalEnergy| Department of Energy

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home Room NewsInformationJesse BergkampCentermillion toMSDSMaterialsMathematical Statisticians

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative FuelsofProgram: Report15 Meeting StateOctober 22, 2014Departmentof Energy

  18. Presolar Stardust in the Solar System: Implications for Nucleosynthesis and Galactic

    E-Print Network [OSTI]

    Nittler, Larry R.

    Presolar Stardust in the Solar System: Implications for Nucleosynthesis and Galactic Chemical, interstellar dust, nucleosynthesis, galactic chemical evolution, isotopes PACS: 96.30.Za, 96.30.Vb, 97.10.Cv

  19. Primordial Li abundance and massive particles

    SciTech Connect (OSTI)

    Latin-Capital-Letter-Eth apo, H.

    2012-10-20

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

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

    E-Print Network [OSTI]

    Lattanzio, John

    NUCLEOSYNTHESIS IN INTERMEDIATE MASS STARS JOHN C. LATTANZIO AND CHERYL A. FROST Department AND PETER R. WOOD Mount Stromlo and Siding Springs Observatories, ANU Abstract. We discuss nucleosynthesis lagging somewhat behind. Studies are desperately needed of the nucleosynthesis which occurs during

  1. Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars

    E-Print Network [OSTI]

    Cowan, John

    Abundance Signatures in Halo Stars: Clues to Nucleosynthesis in the First Stars John J. Cowan-based telescopes to make extensive studies of Galactic halo stars. These stars contain the nucleosynthesis products the earliest Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics

  2. Nucleosynthesis Supernova Explosions Final Stages of Stellar Evolution For Take Away Final Stages of Stellar Evolution

    E-Print Network [OSTI]

    Hörandel, Jörg R.

    Nucleosynthesis Supernova Explosions Final Stages of Stellar Evolution For Take Away Final Stages.XII.2006 Seminar on Astroparticle Physics - Cosmic Rays #12;Nucleosynthesis Supernova Explosions Final are supernova explosions and which different types exist? Where do heavy elements come from? #12;Nucleosynthesis

  3. Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the

    E-Print Network [OSTI]

    Lattanzio, John

    Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the AGB Phase John C on the nucleosynthesis and mixing mechanisms in low­ and intermediate­ mass stars. In addition to explicit studies grains from meteorites. This places strong constraints on nucleosynthesis and mixing in low

  4. NUCLEOSYNTHESIS IN THE EARLY GALAXY F. Montes,1,2,3

    E-Print Network [OSTI]

    Cowan, John

    NUCLEOSYNTHESIS IN THE EARLY GALAXY F. Montes,1,2,3 T. C. Beers,2,4 J. Cowan,5 T. Elliot,2,3,6 K the observations. Subject headinggs: Galaxy: abundances -- nuclear reactions, nucleosynthesis, abundances -- stars-abundances and subtracting them from the observed solar system abundances. If there is an addi- tional nucleosynthesis

  5. Neutrinos and nucleosynthesis in core-collapse supernovae

    SciTech Connect (OSTI)

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

    2014-01-01

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

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

    Broader source: Energy.gov [DOE]

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

  7. Astrophysical Models of r-Process Nucleosynthesis: An Update

    E-Print Network [OSTI]

    Yong-Zhong Qian

    2012-01-24

    An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of ~10^-3 times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

  8. Astrophysical models of r-process nucleosynthesis: An update

    SciTech Connect (OSTI)

    Qian Yongzhong [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2012-11-12

    An update on astrophysical models for nucleosynthesis via rapid neutron capture, the r process, is given. A neutrino-induced r process in supernova helium shells may have operated up to metallicities of {approx} 10{sup -3} times the solar value. Another r-process source, possibly neutron star mergers, is required for higher metallicities.

  9. www.universitypressscholarship.com Oxford University Press 2011. All rights reserved. 2. University Press

    E-Print Network [OSTI]

    Wu, Yih-Min

    www.universitypressscholarship.com Oxford University Press 2011. All rights reserved. 1. 2. University Press Scholarship Online? 3. UPSO 4. 5. 6. 7. (Quick search) 8. 9. DOIs 10. 11. 12. 13. () 14. University Press Scholarship Online(UPSO) Oxford Scholarship Online #12;www

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

    E-Print Network [OSTI]

    Giles, Mike

    Carlo Mike Giles (Oxford) Monte Carlo methods May 30­31, 2013 2 / 33 SDEs in Finance In computational finance, stochastic differential equations are used to model the behaviour of stocks interest rates exchange rates weather electricity/gas demand crude oil prices . . . Mike Giles (Oxford) Monte Carlo

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

    E-Print Network [OSTI]

    Giles, Mike

    Carlo Mike Giles (Oxford) Monte Carlo methods May 30­31, 2013 2 / 33 #12;SDEs in Finance In computational finance, stochastic differential equations are used to model the behaviour of stocks interest rates exchange rates weather electricity/gas demand crude oil prices . . . Mike Giles (Oxford) Monte

  12. Chemistry Course Reading List * Physical Chemistry, P W Atkins, Oxford University Press (8th

    E-Print Network [OSTI]

    Oxford, University of

    Chemistry Course Reading List * Physical Chemistry, P W Atkins, Oxford University Press (8th edn.) 2006, [7th edn. 2001] * Inorganic Chemistry, Shriver and Atkins, Oxford University Press (4th edn) 2006, (previous edn., 1999] Chemistry of the Elements, Greenwood & Earnshaw, Pergamon (2nd edn.), 1997 [1st edn

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Information Serbia-EnhancingEt Al.,Turin, NewArkansas:StandardsMichiganHilton, NewVermont (UtilityOxford,

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

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers CoMadison - IL 26ProcessingOxford OH Site

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPI Ventures LtdNeville, Ohio:Archaeological PermitsMilford, New Jersey:Oxford,

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver CoreOxford SolarOhio: EnergyUnited

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

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX E LISTStar EnergyLawler, Iowa (UtilityIowaIowa (Utility Company) JumpOwensboro,Oxford,

  18. Effects of axions on Nucleosynthesis in massive stars

    E-Print Network [OSTI]

    Aoyama, Shohei

    2015-01-01

    We investigate the effect of the axion cooling on the nucleosynthesis in a massive star with $16M_{\\odot}$ by standard stellar evolution calculation. We find that the axion cooling suppresses the nuclear reactions in carbon, oxygen and silicon burning phases because of the extraction of the energy. As a result, larger amounts of the already synthesized neon and magnesium remain without being consumed to produce further heavier elements. Even in the case with the axion-photon coupling constant $g_{a\\gamma}= 10^{-11}$ GeV$^{-1}$, which is six times smaller than the current upper limit, the amount of neon and magnesium that remain just before the core-collapse supernova explosion is considerably larger than the standard value. This implies that we could give a more stringent constraint on $g_{a\\gamma}$ from the nucleosynthesis of heavy elements in massive stars.

  19. HOW MANY NUCLEOSYNTHESIS PROCESSES EXIST AT LOW METALLICITY?

    SciTech Connect (OSTI)

    Hansen, C. J. [Landessternwarte, ZAH, Heidelberg University, Königstuhl 12, D-69117 Heidelberg (Germany); Montes, F. [Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, MI 48824 (United States); Arcones, A., E-mail: cjhansen@lsw.uni-heidelberg.de, E-mail: cjhansen@dark-cosmology.dk, E-mail: montes@nscl.msu.edu, E-mail: almudena.arcones@physik.tu-darmstadt.de [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr. 2, Darmstadt D-64289 (Germany)

    2014-12-20

    Abundances of low-metallicity stars offer a unique opportunity to understand the contribution and conditions of the different processes that synthesize heavy elements. Many old, metal-poor stars show a robust abundance pattern for elements heavier than Ba, and a less robust pattern between Sr and Ag. Here we probe if two nucleosynthesis processes are sufficient to explain the stellar abundances at low metallicity, and we carry out a site independent approach to separate the contribution from these two processes or components to the total observationally derived abundances. Our approach provides a method to determine the contribution of each process to the production of elements such as Sr, Zr, Ba, and Eu. We explore the observed star-to-star abundance scatter as a function of metallicity that each process leads to. Moreover, we use the deduced abundance pattern of one of the nucleosynthesis components to constrain the astrophysical conditions of neutrino-driven winds from core-collapse supernovae.

  20. Statistical Methods for Thermonuclear Reaction Rates and Nucleosynthesis Simulations

    E-Print Network [OSTI]

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

    2014-01-01

    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 ...

  1. ?-decay spectroscopy for the r-process nucleosynthesis

    SciTech Connect (OSTI)

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

    2014-05-09

    Series of decay spectroscopy experiments, utilizing of high-purity Ge detectors and double-sided silicon-strip detectors, have been conducted to harvest the decay properties of very exotic nuclei relevant to the r-process nucleosynthesis at the RIBF. The decay properties such as ?-decay half-lives, low-lying states, ?-delayed neutron emissions, isomeric states, and possibly Q{sub ?} of the very neutron-rich nuclei are to be measured to give significant constraints in the uncertainties of nuclear properties for the r-process nucleosynthesis. Recent results of ?? spectroscopy study using in-flight fission of {sup 238}U-beam will be presented together with our future perspectives.

  2. Nucleosynthesis in the ejecta of neutron star mergers

    SciTech Connect (OSTI)

    Wanajo, Shinya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Sekiguchi, Yuichiro; Kiuchi, Kenta; Shibata, Masaru [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Nishimura, Nobuya [Astrophysics Group, iEPSAM, Keele University, Keele, ST5 5BG (United Kingdom); Kyutoku, Koutarou [Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)

    2014-05-02

    We present, for the first time, the result of nucleosynthesis calculations based on the fully general-relativistic simulation of a NS-NS merger with approximate neutrino transport taken into account. It is found that the bulk of the dynamical ejecta are appreciably shock-heated and neutrino-processed, resulting in a wide range of electron fraction, Y{sub e} ? 0.1-0.4. The mass-averaged abundance distribution of calculated nucleosynthesis yields is in remarkable agreement with the full-mass range (A ? 90-240) of the solar r-process curve. This implies, if our model is representative of such events, that the dynamical ejecta of NS-NS mergers can be the origin of the Galactic r-process nuclei.

  3. Nucleosynthesis in Metal-Free and Metal-Poor Stars

    E-Print Network [OSTI]

    Yong-Zhong Qian

    2008-07-04

    There have been a number of important recent developments in theoretical and observational studies of nucleosynthesis, especially regarding nucleosynthetic sources at low metallicities. Those selected for discussion here include the origin of Li6, the primary production of N, the s-process, and the supernova sources for three groups of metals: (1) C to Zn with mass numbers A<70, (2) Sr to Ag with A~90-110, and (3) r-process nuclei with A~130 and above.

  4. Nucleosynthesis in the accretion disks of Type II collapsars

    E-Print Network [OSTI]

    Indrani Banerjee; Banibrata Mukhopadhyay

    2013-05-08

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

  5. Nucleosynthesis in neutrino-driven winds in hypernovae

    E-Print Network [OSTI]

    Fujibayashi, Sho; Sekiguchi, Yuichiro

    2015-01-01

    We investigate the nucleosynthesis in the neutrino-driven winds blown off from a $3M_\\odot$ massive proto-neutron star temporarily formed during the collapse of a $100M_\\odot$ star. Such massive proto-neutron stars would be formed in hypernovae. We construct steady and spherically symmetric wind solutions. We set large neutrino luminosities of $\\sim 10^{53}\\ {\\rm erg\\ s^{-1}}$ and average energies of electron neutrinos and antineutrinos in the ranges of $\\epsilon_{\

  6. Nucleosynthesis in early supernova winds III: No significant contribution from neutron-rich pockets

    E-Print Network [OSTI]

    R. D. Hoffman; J. Pruet; J. L. Fisker; H. -T. Janka; R. Burras; S. E. Woosley

    2007-12-18

    Recent nucleosynthesis calculations of Type II supernovae using advanced neutrino transport determine that the early neutrino winds are proton-rich. However, a fraction of the ejecta emitted at the same time is composed of neutron-rich pockets. In this paper we calculate the nucleosynthesis contribution from the neutron-rich pockets in the hot convective bubbles of a core-collapse supernova and show that they do not contribute significantly to the total nucleosynthesis.

  7. Nuclear Ashes: Reviewing Thirty Years of Nucleosynthesis in Classical Novae

    E-Print Network [OSTI]

    Jordi Jose

    2002-09-10

    One of the observational evidences in support of the "thermonuclear runaway model" for the classical nova outburst relies on the accompanying nucleosynthesis. In this paper, we stress the relevant role played by nucleosynthesis in our understanding of the nova phenomenon by constraining models through a comparison with both the atomic abundance determinations from the ejecta and the isotopic ratios measured in presolar grains of a likely nova origin. Furthermore, the endpoint of nova nucleosynthesis provides hints for the understanding of the mixing process responsible for the enhanced metallicities found in the ejecta, and reveals also information on the properties of the underlying white dwarf (mass, luminosity...). We discuss first the interplay between nova outbursts and the Galactic chemical abundances: Classical nova outbursts are expected to be the major source of 13C, 15N and 17O in the Galaxy, and to contribute to the abundances of other species with A < 40, such as 7Li or 26Al. We describe the main nuclear path during the course of the explosion, with special emphasis on the synthesis of radioactive species, of particular interest for the gamma-ray output predicted from novae (7Li, 18F, 22Na, 26Al). An overview of the recent discovery of presolar nova candidate grains, as well as a discussion of the role played by nuclear uncertainties associated with key reactions of the NeNa-MgAl and Si-Ca regions, are also given.

  8. Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity

    E-Print Network [OSTI]

    Woosley, S E

    2007-01-01

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

  9. Quantification of nuclear uncertainties in nucleosynthesis of elements beyond Iron

    E-Print Network [OSTI]

    T. Rauscher

    2014-12-22

    Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Generally higher temperatures and nuclear level densities lead to stronger contributions of transitions on excited target states. This may prevent cross section measurements to determine stellar reaction rates and theory contributions remain important. Furthermore, measurements often are not feasible in the astrophysically relevant energy range. Sensitivity analysis allows not only to determine the contributing nuclear properties but also is a handy tool for experimentalists to interpret the impact of their data on predicted cross sections and rates. It can also speed up future input variation studies of nucleosynthesis by simplifying an intermediate step in the full calculation sequence. Large-scale predictions of sensitivities and ground-state contributions to the stellar rates are presented, allowing an estimate of how well rates can be directly constrained by experiment. The reactions 185W(n,gamma) and 186W(gamma,n) are discussed as application examples. Studies of uncertainties in abundances predicted in nucleosynthesis simulations rely on the knowledge of reaction rate errors. An improved treatment of uncertainty analysis is presented as well as a recipe for combining experimental data and theory to arrive at a new reaction rate and its uncertainty. As an example, it is applied to neutron capture rates for the s-process, leading to larger uncertainties than previously assumed.

  10. Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity

    E-Print Network [OSTI]

    S. E. Woosley; A. Heger

    2007-02-06

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

  11. Primordial magnetic field limits from cosmological data

    SciTech Connect (OSTI)

    Kahniashvili, Tina [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ontario P3E 2C (Canada); Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Tevzadze, Alexander G. [Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Faculty of Exact and Natural Sciences, Tbilisi State University, 1 Chavchavadze Avenue, Tbilisi, GE-0128 (Georgia); Sethi, Shiv K. [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); Pandey, Kanhaiya [Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); Ratra, Bharat [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)

    2010-10-15

    We study limits on a primordial magnetic field arising from cosmological data, including that from big bang nucleosynthesis, cosmic microwave background polarization plane Faraday rotation limits, and large-scale structure formation. We show that the physically relevant quantity is the value of the effective magnetic field, and limits on it are independent of how the magnetic field was generated.

  12. Nuclear physics and cosmology

    SciTech Connect (OSTI)

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

    2014-05-09

    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.

  13. The Impact of LUNA Results on Astroparticle Physics

    SciTech Connect (OSTI)

    Gustavino, Carlo [INFN Sezione di Roma, I-00185 Roma (Italy)

    2011-10-28

    LUNA (Laboratory for Underground Nuclear Astrophysics) is devoted to measure nuclear cross sections relevant in astroparticle physics. The facility operates underground, at the 'Laboratori Nazionali del Gran Sasso'(LNGS), where the cosmic ray induced background is very low. The LUNA measurements are important in neutrino physics, in the study of the Sun and other celestial bodies, in the Big Bang Nucleosynthesis.

  14. arXiv:1012.0242v1[astro-ph.SR]1Dec2010 Nucleosynthesis and chemical evolution of

    E-Print Network [OSTI]

    Maciel, Walter Junqueira

    arXiv:1012.0242v1[astro-ph.SR]1Dec2010 Nucleosynthesis and chemical evolution of intermediate to investigate the nucleosynthesis and chemical evolution of intermediate mass stars. In these objects accurate) are an excellent laboratory to investigate the nucleosynthesis and chemical evolution of intermediate mass stars

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

    SciTech Connect (OSTI)

    Reddy, Sanjay

    2013-09-06

    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.

  16. Experimental studies of reactions relevant for ?-process nucleosynthesis

    SciTech Connect (OSTI)

    Scholz, P.; Endres, J.; Hennig, A.; Mayer, J.; Netterdon, L.; Zilges, A. [Institute for Nuclear Physics, University of Cologne (Germany); Sauerwein, A. [Institute for Applied Physics, Goethe University, Frankfurt am Main, Germany and Institute for Nuclear Physics, University of Cologne (Germany)

    2014-05-09

    We report on our recent experimental studies of reactions relevant for the ? process nucleosynthesis. Applying the activation method using the Cologne Clover Counting Setup total cross sections of the reactions {sup 168}Yb(?,?), {sup 168}Yb(?,n), and {sup 187}Re(?,n) could be obtained. Furthermore, the reaction {sup 89}Y(p,?) was investigated via the in-beam technique with HPGe detectors at the high-efficiency g-ray spectrometer HORUS in Cologne in order to determine partial and total cross sections.

  17. Neutron capture rates and r-process nucleosynthesis

    E-Print Network [OSTI]

    R. Surman; M. Mumpower; G. C. McLaughlin; R. Sinclair; W. R. Hix; K. L. Jones

    2013-08-31

    Simulations of r-process nucleosynthesis require nuclear physics information for thousands of neutron-rich nuclear species from the line of stability to the neutron drip line. While arguably the most important pieces of nuclear data for the r-process are the masses and beta decay rates, individual neutron capture rates can also be of key importance in setting the final r-process abundance pattern. Here we consider the influence of neutron capture rates in forming the A~80 and rare earth peaks.

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

    E-Print Network [OSTI]

    Giles, Mike

    Monte Carlo Methods for Uncertainty Quantification Mike Giles Mathematical Institute, University of Oxford ERCOFTAC course on Mathematical Methods and Tools in Uncertainty Management and Quantification Lecture 1: Introduction and Monte Carlo basics some model applications random number generation Monte

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

    E-Print Network [OSTI]

    Giles, Mike

    Monte Carlo Methods for Uncertainty Quantification Mike Giles Mathematical Institute, University of Oxford ERCOFTAC course on Mathematical Methods and Tools in Uncertainty Management and Quantification: Introduction and Monte Carlo basics some model applications random number generation Monte Carlo estimation

  20. Department of Earth Sciences South Parks Road, Oxford OX1 3AN

    E-Print Network [OSTI]

    Henderson, Gideon

    Department of Earth Sciences South Parks Road, Oxford OX1 3AN If you are new to the Department offers two schemes which help parents save tax and national insurance on their childcare costs: Salary

  1. InspiredResearch News from the Department of Computer Science, University of Oxford

    E-Print Network [OSTI]

    Oxford, University of

    computer ­ p5 Fiat LuxEclipse sheds light on solar panel modelling ­ p12 CompSciOxford Department) funding for data wrangling innovation (p7); Marta Kwiatkowska was jointly awarded a major EPSRC project

  2. Director: Dr Nigel Bowles 1A South Parks Road, Oxford, OX1 3UB, United Kingdom

    E-Print Network [OSTI]

    Oxford, University of

    Director: Dr Nigel Bowles 1A South Parks Road, Oxford, OX1 3UB, United Kingdom +44 1865 282 705-First Century America: What Sustains the Ruckus? #12;Wednesday 29 April 17:00-18:30 Abortion in Context: Law

  3. Timothy O'Connor, Persons & Causes: The Metaphysics of Free Will. Oxford & New York: Oxford University Press, 2000. Pp. Xv and 135. $35.00

    E-Print Network [OSTI]

    Buckareff, Andrei A.

    Timothy O'Connor, Persons & Causes: The Metaphysics of Free Will. Oxford & New York: Oxford University Press, 2000. Pp. Xv and 135. $35.00 Andrei A. Buckareff University of Rochester In the past decade, Timothy O'Connor has established himself... as one of the leading defenders of the agent-causal theory of free action. In Persons & Causes, O'Connor provides a sophisticated defense of incompatibilist freedom and his own agent-causal and volitional theory of the etiology of action. He includes...

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

    E-Print Network [OSTI]

    A. Arcones; F. -K. Thielemann

    2012-07-11

    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.

  5. Nucleosynthesis in the Ejecta of Neutron Star Mergers

    E-Print Network [OSTI]

    Dirk Martin; Albino Perego; Almudena Arcones; Oleg Korobkin; Friedrich-Karl Thielemann

    2015-09-25

    Heavy elements like gold, platinum or uranium are produced in the r-process, which needs neutron-rich and explosive environments. Neutron star mergers are a promising candidate for an r-process site. They exhibit three different channels for matter ejection fulfilling these conditions: dynamic ejecta due to tidal torques, neutrino-driven winds and evaporating matter from the accretion disk. We present a first study of the integrated nucleosynthesis for a neutrino-driven wind from a neutron star merger with a hyper-massive neutron star. Trajectories from a recent hydrodynamical simulation are divided into four different angle regions and post-processed with a reaction network. We find that the electron fraction varies around $Y_e \\approx 0.1 - 0.4$, but its distribution differs for every angle of ejection. Hence, the wind ejecta do not undergo a robust r-process, but rather possess distinct nucleosynthesis yields depending on the angle range. Compared to the dynamic ejecta, a smaller amount of neutron-rich matter gets unbound, but the production of lighter heavy elements with $A \\lesssim 130$ in the neutrino-driven wind can complement the strong r-process of the dynamic ejecta.

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

    E-Print Network [OSTI]

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

    2005-09-13

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

  7. Neutron-capture nucleosynthesis in the first stars

    SciTech Connect (OSTI)

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

    2014-04-01

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

  8. Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers

    E-Print Network [OSTI]

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

    2015-01-01

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

  9. Photon-induced Nucleosynthesis: Current Problems and Experimental Approaches

    E-Print Network [OSTI]

    P. Mohr; Zs. Fulop; H. Utsunomiya

    2007-05-16

    Photon-induced reactions play a key role in the nucleosynthesis of rare neutron-deficient p-nuclei. The paper focuses on (gamma,alpha), (gamma,p), and (gamma,n) reactions which define the corresponding p-process path. The relation between stellar reaction rates and laboratory cross sections is analyzed for photon-induced reactions and their inverse capture reactions to evaluate various experimental approaches. An improved version S_C(E) of the astrophysical S-factor is suggested which is based on the Coulomb wave functions. S_C(E) avoids the apparent energy dependence which is otherwise obtained for capture reactions on heavy nuclei. It is found that a special type of synchrotron radiation available at SPring-8 that mimics stellar blackbody radiation at billions of Kelvin is a promising tool for future experiments. By using the blackbody synchrotron radiation, sufficient event rates for (gamma,alpha) and (gamma,p) reactions in the p-process path can be expected. These experiments will provide data to improve the nuclear parameters involved in the statistical model and thus reduce the uncertainties of nucleosynthesis calculations.

  10. Challenges in nucleosynthesis of trans-iron elements

    SciTech Connect (OSTI)

    Rauscher, T. [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, Hatfield AL10 9AB, United Kingdom and Department of Physics, University of Basel, CH-4056 Basel (Switzerland)] [Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, Hatfield AL10 9AB, United Kingdom and Department of Physics, University of Basel, CH-4056 Basel (Switzerland)

    2014-04-15

    Nucleosynthesis beyond Fe poses additional challenges not encountered when studying astrophysical processes involving light nuclei. Astrophysical sites and conditions are not well known for some of the processes involved. On the nuclear physics side, different approaches are required, both in theory and experiment. The main differences and most important considerations are presented for a selection of nucleosynthesis processes and reactions, specifically the s-, r-, ?-, and ?p-processes. Among the discussed issues are uncertainties in sites and production conditions, the difference between laboratory and stellar rates, reaction mechanisms, important transitions, thermal population of excited states, and uncertainty estimates for stellar rates. The utility and limitations of indirect experimental approaches are also addressed. The presentation should not be viewed as confining the discussed problems to the specific processes. The intention is to generally introduce the concepts and possible pitfalls along with some examples. Similar problems may apply to further astrophysical processes involving nuclei from the Fe region upward and/or at high plasma temperatures. The framework and strategies presented here are intended to aid the conception of future experimental and theoretical approaches.

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

    E-Print Network [OSTI]

    Oxford, University of

    Road Building . Oxford OX1 3UQ T: +44 (0)1865 271084 . F: +44 (0)1865 281447 . E: csae@cgdev.org. Address: Center for Global Development Europe, 54 Wilton Road, London SW1V 1DE Georgetown University success (Alden Wily, 2003; Deininger et al., 2008). As a result of sustained informal growth, unchecked

  12. Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae

    SciTech Connect (OSTI)

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

    2006-09-21

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

  13. Nucleosynthesis in Type I X-ray Bursts

    E-Print Network [OSTI]

    A. Parikh; J. José; G. Sala; C. Iliadis

    2012-11-26

    Type I X-ray bursts are thermonuclear explosions that occur in the envelopes of accreting neutron stars. Detailed observations of these phenomena have prompted numerous studies in theoretical astrophysics and experimental nuclear physics since their discovery over 35 years ago. In this review, we begin by discussing key observational features of these phenomena that may be sensitive to the particular patterns of nucleosynthesis from the associated thermonuclear burning. We then summarize efforts to model type I X-ray bursts, with emphasis on determining the nuclear physics processes involved throughout these bursts. We discuss and evaluate limitations in the models, particularly with regard to key uncertainties in the nuclear physics input. Finally, we examine recent, relevant experimental measurements and outline future prospects to improve our understanding of these unique environments from observational, theoretical and experimental perspectives.

  14. Nucleosynthesis of heavy elements in gamma ray bursts

    E-Print Network [OSTI]

    ,

    2015-01-01

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

  15. Fission Cycling in Supernova Nucleosynthesis: Active-Sterile Neutrino Oscillations

    E-Print Network [OSTI]

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

    2006-02-26

    We investigate nucleosynthesis in the supernovae post-core bounce neutrino-driven wind environment in the presence of active-sterile neutrino transformation. We consider active-sterile neutrino oscillations for a range of mixing parameters: vacuum mass-squared differences of 0.1 eV^2 10^-4. We find a consistent r-process pattern for a large range of mixing parameters that is in rough agreement with the halo star CS 22892-052 abundances and the pattern shape is determined by fission cycling. We find that the allowed region for the formation of the r-process peaks overlaps the LSND and NSBL (3+1) allowed region.

  16. On Solar System and Cosmic Rays Nucleosynthesis and Spallation Processes

    E-Print Network [OSTI]

    Stepan G. Mashnik

    2000-08-24

    A brief survey of nuclide abundances in the solar-system and in cosmic rays and of the believed mechanisms of their synthesis is given. The role of spallation processes in nucleosynthesis is discussed. A short review of recent measurements, compilations, calculations, and evaluations of spallation cross sections relevant to nuclear astrophysics is given as well. It is shown that in some past astrophysical simulations, old experimental nuclear data and theoretical cross sections that are in poor agreement with recent measurements and calculations were used. New astrophysical simulations using recently measured and reliably calculated nuclear cross sections, further researches in obtaining better cross sections, and production of evaluated spallation cross sections libraries for astrophysics are suggested.

  17. PRESUPERNOVA EVOLUTION AND EXPLOSIVE NUCLEOSYNTHESIS OF ZERO METAL MASSIVE STARS

    SciTech Connect (OSTI)

    Limongi, M. [Istituto Nazionale di Astrofisica-Osservatorio Astronomico di Roma, Via Frascati 33, I-00040, Monteporzio Catone, Roma (Italy); Chieffi, A., E-mail: marco.limongi@oa-roma.inaf.it, E-mail: alessandro.chieffi@inaf.it [Centre for Stellar and Planetary Astrophysics, School of Mathematical Sciences, P.O. Box, 28M, Monash University, Victoria 3800 (Australia)

    2012-04-01

    We present a new set of zero metallicity models in the range 13-80 M{sub Sun} together to the associated explosive nucleosynthesis. These models are fully homogeneous with the solar metallicity set we published in Limongi and Chieffi and will be freely available at the Online Repository for the FRANEC Evolutionary Output Web site. A comparison between these yields and an average star that represents the average behavior of most of the very metal-poor stars in the range -5.0 < [Fe/H] < -2.5 confirms previous findings that only a fraction of the elemental [X/Fe] may be fitted by the ejecta of standard core collapse supernovae.

  18. British Geomorphological Research Group, Annual Meeting, Oxford, 2003. An analysis and classification of 'barchan' dunes on Mars.

    E-Print Network [OSTI]

    Bourke, Mary C.

    and classification of 'barchan' dunes on Mars. Bourke, M.C., and Balme, M. School of Geography and the Environment, University of Oxford, Oxford, OX1 3TB, UK. Mary.bourke@geog.ox.ac.uk Martian sand dunes have the potential and morphodynamics. Recognition of the characteristics of both recent and ancient dunes is the first step towards

  19. Primordial nucleosynthesis as a probe of fundamental physics parameters

    E-Print Network [OSTI]

    Thomas Dent; Steffen Stern; Christof Wetterich

    2007-08-10

    We analyze the effect of variation of fundamental couplings and mass scales on primordial nucleosynthesis in a systematic way. The first step establishes the response of primordial element abundances to the variation of a large number of nuclear physics parameters, including nuclear binding energies. We find a strong influence of the n-p mass difference (for the 4He abundance), of the nucleon mass (for deuterium) and of A=3,4,7 binding energies (for 3He, 6Li and 7Li). A second step relates the nuclear parameters to the parameters of the Standard Model of particle physics. The deuterium, and, above all, 7Li abundances depend strongly on the average light quark mass hat{m} \\equiv (m_u+m_d)/2. We calculate the behaviour of abundances when variations of fundamental parameters obey relations arising from grand unification. We also discuss the possibility of a substantial shift in the lithium abundance while the deuterium and 4He abundances are only weakly affected.

  20. Nucleosynthesis in neutrino-driven winds after neutron star mergers

    E-Print Network [OSTI]

    Martin, Dirk; Arcones, Almudena; Thielemann, Friedrich-Karl; Korobkin, Oleg; Rosswog, Stephan

    2015-01-01

    We present a comprehensive nucleosynthesis study of the neutrino-driven wind in the aftermath of a binary neutron star merger. Our focus is the initial remnant phase when a massive central neutron star is present. Using tracers from a recent hydrodynamical simulation, we determine total masses and integrated abundances to characterize the composition of unbound matter. We find that the nucleosynthetic yields depend sensitively on both the life time of the massive neutron star and the polar angle. Matter in excess of up to $9 \\cdot 10^{-3} M_\\odot$ becomes unbound until $\\sim 200~{\\rm ms}$. Due to electron fractions of $Y_{\\rm e} \\approx 0.2 - 0.4$ mainly nuclei with mass numbers $A < 130$ are synthesized, complementing the yields from the earlier dynamic ejecta. Mixing scenarios with these two types of ejecta can explain the abundance pattern in r-process enriched metal-poor stars. Additionally, we calculate heating rates for the decay of the freshly produced radioactive isotopes. The resulting light curve...

  1. Chaos and turbulent nucleosynthesis prior to a supernova explosion

    SciTech Connect (OSTI)

    Arnett, W. D., E-mail: darnett@as.arizona.edu; Meakin, C., E-mail: cmeakin@as.arizona.edu [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson AZ 85721 (United States); Viallet, M., E-mail: mviallet@mpa-garching.mpg.de [Max-Planck Institut für Astrophysik, Karl Schwarzschild Strasse 1, Garching, D-85741 (Germany)

    2014-04-15

    Three-dimensional (3D), time dependent numerical simulations of flow of matter in stars, now have sufficient resolution to be fully turbulent. The late stages of the evolution of massive stars, leading up to core collapse to a neutron star (or black hole), and often to supernova explosion and nucleosynthesis, are strongly convective because of vigorous neutrino cooling and nuclear heating. Unlike models based on current stellar evolutionary practice, these simulations show a chaotic dynamics characteristic of highly turbulent flow. Theoretical analysis of this flow, both in the Reynolds-averaged Navier-Stokes (RANS) framework and by simple dynamic models, show an encouraging consistency with the numerical results. It may now be possible to develop physically realistic and robust procedures for convection and mixing which (unlike 3D numerical simulation) may be applied throughout the long life times of stars. In addition, a new picture of the presupernova stages is emerging which is more dynamic and interesting (i.e., predictive of new and newly observed phenomena) than our previous one.

  2. Supernova nucleosynthesis and the physics of neutrino oscillation

    SciTech Connect (OSTI)

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

    2012-11-20

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

  3. Restrictions on the lifetime of sterile neutrinos from primordial nucleosynthesis

    SciTech Connect (OSTI)

    Ruchayskiy, Oleg [Physics Department, Theory Division, CERN, CH-1211 Geneva 23 (Switzerland); Ivashko, Artem, E-mail: oleg.ruchayskiy@epfl.ch, E-mail: ivashko@lorentz.leidenuniv.nl [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, Niels Bohrweg 2, Leiden (Netherlands)

    2012-10-01

    We analyze the influence of sterile neutrinos with the masses in the MeV range on the primordial abundances of Helium-4 and Deuterium. We solve explicitly the Boltzmann equations for all particle species, taking into account neutrino flavour oscillations and demonstrate that the abundances are sensitive mostly to the sterile neutrino lifetime and only weakly to the way the active-sterile mixing is distributed between flavours. The decay of these particles also perturbs the spectra of (decoupled) neutrinos and heats photons, changing the ratio of neutrino to photon energy density, that can be interpreted as extra neutrino species at the recombination epoch. We derive upper bounds on the lifetime of sterile neutrinos based on both astrophysical and cosmological measurements of Helium-4 and Deuterium. We also demonstrate that the recent results of Izotov and Thuan [1], who find 2? higher than predicted by the standard primordial nucleosynthesis value of Helium-4 abundance, are consistent with the presence in the plasma of sterile neutrinos with the lifetime 0.01–2 seconds.

  4. The r-process nucleosynthesis: Nuclear physics challenges

    SciTech Connect (OSTI)

    Goriely, S.

    2012-10-20

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

  5. Oxford Review of Education, Vol. 2, No. 3, 1976 Head and Hand: Rhetorical Resources in British

    E-Print Network [OSTI]

    Shapin, Steven

    Oxford Review of Education, Vol. 2, No. 3, 1976 Head and Hand: Rhetorical Resources in British treatments of the process of education tend to be developed on the basis of particular conceptions shall examine these conceptions as they are manifested in a selection of educational writings

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

    E-Print Network [OSTI]

    Oxford, University of

    it is made, they develop new or improved materials to meet engineering specifications, and they devise for telecommunications, semiconductors and other materials for photovoltaic energy generation, and silicon microchipsMaterials Science at Oxford is an interdisciplinary subject that makes use of knowledge from

  7. Request for information from the University of Oxford Please send completed form to: Information Officer

    E-Print Network [OSTI]

    Request for information from the University of Oxford Please send completed form to: Information: E-mail address: Contact tel. no: INFORMATION REQUESTED (please see notes below) Please describe the information you are requesting, providing as much detail on the subject matter as possible in order to help us

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

    E-Print Network [OSTI]

    Giles, Mike

    / 24 #12;SDEs in Finance In computational finance, stochastic differential equations are used to model the behaviour of stocks interest rates exchange rates weather electricity/gas demand crude oil prices . . . Mike Giles (Oxford) Monte Carlo methods 2 3 / 24 #12;SDEs in Finance Stochastic differential equations

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

    E-Print Network [OSTI]

    Giles, Mike

    in Finance In computational finance, stochastic differential equations are used to model the behaviour of stocks interest rates exchange rates weather electricity/gas demand crude oil prices . . . Mike Giles (Oxford) Monte Carlo methods 2 3 / 24 SDEs in Finance Stochastic differential equations are just ordinary

  10. Science and Medicine Dispatch reader survey 1. What is your status at Oxford University?

    E-Print Network [OSTI]

    Wallace, Mark

    1 of 6 Science and Medicine Dispatch reader survey 1. What is your status at Oxford University question 1 #12;2 of 6 3. Do you read the Science and Medicine Libraries newsletter, Science and Medicine. How do you receive Science and Medicine Dispatch? Select all that apply. Response Percent Response

  11. Free Will and the Bounds of the Self1 [Forthcoming in Robert Kane, ed. Oxford Handbook

    E-Print Network [OSTI]

    Knobe, Joshua

    1 Free Will and the Bounds of the Self1 [Forthcoming in Robert Kane, ed. Oxford Handbook of Free of Arizona If you start taking courses in contemporary cognitive science, you will soon encounter is fundamentally confused or wrongheaded. They think that the confusion here can be cleared up just by saying

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

    E-Print Network [OSTI]

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

    2002-06-03

    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.

  13. Hot Bottom Burning Nucleosynthesis in 6 M fi Stellar Models J. C. Lattanzio and C. A. Frost a , R. C. Cannon b , and P. R. Wood c .

    E-Print Network [OSTI]

    Lattanzio, John

    1 Hot Bottom Burning Nucleosynthesis in 6 M fi Stellar Models J. C. Lattanzio and C. A. Frost a , R, Australia We present a brief summary of some nucleosynthesis calculations for 6 M fi stellar models. Theoretical studies are desperately needed to quantify the nucleosynthesis which occurs in intermediate mass

  14. Probing the Neutron-Capture Nucleosynthesis History of Galactic James W. Truran 1 , John J. Cowan 2 , Catherine A. Pilachowski 3 and Christopher Sneden 4

    E-Print Network [OSTI]

    Cowan, John

    Probing the Neutron-Capture Nucleosynthesis History of Galactic Matter James W. Truran 1 , John J formation and nucleosynthesis history of Galactic matter. Of particular interest in this regard; ) stars that provide the site for the main s-process nucleosynthesis component during the AGB phase

  15. FE ISOTOPE NUCLEOSYNTHESIS: CONSTRAINTS FROM FE ISOTOPIC ANALYSES OF PRESOLAR SILICATE GRAINS FROM ACFER 094. W. J. Ong and C. Floss. Laboratory for Space Sciences

    E-Print Network [OSTI]

    Floss, Christine

    FE ISOTOPE NUCLEOSYNTHESIS: CONSTRAINTS FROM FE ISOTOPIC ANALYSES OF PRESOLAR SILICATE GRAINS FROM information about fundamental astrophysical processes, such as stellar nucleosynthesis and galactic chemical evolution. Iron is of particular interest because of its importance in s-process nucleosynthesis. However

  16. Post-AGB stars as testbeds of nucleosynthesis in AGB stars

    E-Print Network [OSTI]

    G. Stasinska; R. Szczerba; M. Schmidt; N. Siodmiak

    2006-01-23

    We construct a data base of 125 post-AGB objects (including R CrB and extreme helium stars) with published photospheric parameters (effective temperature and gravity) and chemical composition. We estimate the masses of the post-AGB stars by comparing their position in the (log Teff, log g) plane with theoretical evolutionary tracks of different masses. We construct various diagrams, with the aim of finding clues to AGB nucleosynthesis. This is the first time that a large sample of post-AGB stars has been used in a systematic way for such a purpose and we argue that, in several respects, post-AGB stars should be more powerful than planetary nebulae to test AGB nucleosynthesis. Our main findings are that: the vast majority of objects which do not show evidence of N production from primary C have a low stellar mass (M* nucleosynthesis.

  17. Nucleosynthesis in a massive star associated with magnetohydrodynamical jets from collapsars

    SciTech Connect (OSTI)

    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)

    2012-11-12

    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).

  18. Light-Element Reaction Flow and the Conditions for r-Process Nucleosynthesis

    E-Print Network [OSTI]

    T. Sasaqui; K. Otsuki; T. Kajino; G. J. Mathews

    2006-03-18

    We deduce new constraints on the entropy per baryon ($s/k$), dynamical timescale ($\\tau_{dyn}$), and electron fraction ($Y_{e}$) consistent with heavy element nucleosynthesis in the r-process. We show that the previously neglected reaction flow throu gh the reaction sequence \\atg (n,$\\gamma$)\\Li~ significantly enhances the production of seed nuclei. We analyze the r-process nucleosynthesis in the context of a schematic exponential wi nd model. We show that fewer neutrons per seed nucleus implies that the entropy per baryon required for successful r-process nucleosynthesis must be more than a factor of two higher than previous estimates. This places new constraints on dynamical mo dels for the r-process.

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

    E-Print Network [OSTI]

    Eduardo Bravo; Gabriel Martínez-Pinedo

    2012-04-09

    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)

  20. Supernova SN1987A Bound on Neutrino Spectra for R-Process Nucleosynthesis

    E-Print Network [OSTI]

    C. J. Horowitz

    2002-01-31

    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.

  1. NEUTRINO SPECTRA FROM ACCRETION DISKS: NEUTRINO GENERAL RELATIVISTIC EFFECTS AND THE CONSEQUENCES FOR NUCLEOSYNTHESIS

    SciTech Connect (OSTI)

    Caballero, O. L.; McLaughlin, G. C. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Surman, R., E-mail: lcaballe@uw.edu, E-mail: olcaball@ncsu.edu, E-mail: gail_mclaughlin@ncsu.edu, E-mail: surmanr@union.edu [Department of Physics and Astronomy, Union College, Schenectady, NY 12308 (United States)

    2012-02-01

    Black hole (BH) accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the BH influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from BH accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome.

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

    E-Print Network [OSTI]

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

    2005-11-12

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

  3. Neutrino Spectra from Accretion Disks: Neutrino General Relativistic Effects and the Consequences for Nucleosynthesis

    E-Print Network [OSTI]

    O. L Caballero; G. C. McLaughlin; R. Surman

    2011-05-31

    Black hole accretion disks have been proposed as good candidates for a range of interesting nucleosynthesis, including the r-process. The presence of the black hole influences the neutrino fluxes and affects the nucleosynthesis resulting from the interaction of the emitted neutrinos and hot outflowing material ejected from the disk. We study the impact of general relativistic effects on the neutrinos emitted from black hole accretion disks. We present abundances obtained by considering null geodesics and energy shifts for two different disk models. We find that both the bending of the neutrino trajectories and the energy shifts have important consequences for the nucleosynthetic outcome

  4. In: Encyclopedia of Neuroscience, vol. 9. (2009) L. Squire (Ed.), Oxford: Academic Press, pp, 45-58.

    E-Print Network [OSTI]

    Stevens, Jeffrey

    2009-01-01

    In: Encyclopedia of Neuroscience, vol. 9. (2009) L. Squire (Ed.), Oxford: Academic Press, pp, 45 this problem through the lens of evolutionary biology, asking which aspects of our cognitive machinery

  5. Effects of kination and scalar-tensor cosmologies on sterile neutrinos

    SciTech Connect (OSTI)

    Rehagen, Thomas; Gelmini, Graciela B., E-mail: trehagen@physics.ucla.edu, E-mail: gelmini@physics.ucla.edu [Department of Physics and Astronomy, UCLA, 475 Portola Plaza, Los Angeles, CA 90095 (United States)

    2014-06-01

    We study the effects of kination and scalar-tensor pre-Big Bang Nucleosynthesis cosmologies on the non-resonant production of sterile neutrinos. We show that if the peak of the production rate of sterile neutrinos occurs during a non-standard cosmological phase, the relic number density of sterile neutrinos could be reduced with respect to the number expected in the standard cosmology. Consequently, current bounds on active-sterile neutrino mixing derived from the relic energy density of sterile neutrinos could be greatly relaxed. In particular, we show that the sterile neutrinos which could explain the anomalies found in short-baseline neutrino experiments are compatible with recent joint Planck upper limits on their contribution to the energy density of the Universe in a scalar-tensor or a low-reheating temperature pre-Big Bang Nucleosynthesis cosmology.

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

    E-Print Network [OSTI]

    Oxford, University of

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

  7. Nucleosynthesis of Elements in Low to Intermediate Mass Stars through the AGB Phase

    E-Print Network [OSTI]

    John C. Lattanzio; Arnold I. Boothroyd

    1997-05-23

    We present a review of the main phases of stellar evolution with particular emphasis on the nucleosynthesis and mixing mechanisms in low- and intermediate-mass stars. In addition to explicit studies of the effects of the first, second and third dredge-up, we also discuss cool bottom processing and hot bottom burning.

  8. Modern theories of low-energy astrophysical reactions

    E-Print Network [OSTI]

    L. E. Marcucci; Kenneth M. Nollett; R. Schiavilla; R. B. Wiringa

    2004-02-23

    We summarize recent ab initio studies of low-energy electroweak reactions of astrophysical interest, relevant for both big bang nucleosynthesis and solar neutrino production. The calculational methods include direct integration for np radiative and pp weak capture, correlated hyperspherical harmonics for reactions of A=3,4 nuclei, and variational Monte Carlo for A=6,7 nuclei. Realistic nucleon-nucleon and three-nucleon interactions and consistent current operators are used as input.

  9. MONKEY ERPs 1 In press: to appear in The Oxford Handbook of Event-Related Potential Components. Luck, S.J.

    E-Print Network [OSTI]

    Woodman, Geoffrey F.

    MONKEY ERPs 1 In press: to appear in The Oxford Handbook of Event-Related Potential Components. Luck, S.J. & Kappenman, E.S. (Eds.), New York: Oxford University Press. Homologues of human ERP, Center for Integrative and Cognitive Neuroscience Running Head: MONKEY ERPs Correspondence from

  10. The impact of individual nuclear properties on $r$-process nucleosynthesis

    E-Print Network [OSTI]

    Mumpower, M R; McLaughlin, G C; Aprahamian, A

    2015-01-01

    The astrophysical rapid neutron capture process or `$r$ process' of nucleosynthesis is believed to be responsible for the production of approximately half the heavy element abundances found in nature. This multifaceted problem remains one of the greatest open challenges in all of physics. Knowledge of nuclear physics properties such as masses, $\\beta$-decay and neutron capture rates, as well as $\\beta$-delayed neutron emission probabilities are critical inputs that go into calculations of $r$-process nucleosynthesis. While properties of nuclei near stability have been established, much still remains unknown regarding neutron-rich nuclei far from stability that may participate in the $r$ process. Sensitivity studies gauge the astrophysical response of a change in nuclear physics input(s) which allows for the isolation of the most important nuclear properties that shape the final abundances observed in nature. This review summarizes the extent of recent sensitivity studies and highlights how these studies play ...

  11. Microsoft PowerPoint - Oxford_MiniBooNE_and_SterileNus.ppt

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on darkMicroorganismsnow widelySmall IceatIt hasCoalOxford Seminar

  12. Nucleosynthesis in novae: experimental progress in the determination of nuclear reaction rates

    E-Print Network [OSTI]

    Alain Coc

    2008-01-18

    The sources of nuclear uncertainties in nova nucleosynthesis have been identified using hydrodynamical nova models. Experimental efforts have followed and significantly reduced those uncertainties. This is important for the evaluation of nova contribution to galactic chemical evolution, gamma--ray astronomy and possibly presolar grain studies. In particular, estimations of expected gamma-ray fluxes are essential for the planning of observations with existing or future satellites.

  13. An ERC Starting Grant project on p-process nucleosynthesis concluded

    E-Print Network [OSTI]

    Gyürky, Gy; Szücs, T; Kiss, G G; Fülöp, Zs

    2015-01-01

    In 2008 a Starting Grant project supported by the European Research Council titled "Nuclear reaction studies relevant to the astrophysical p-process nucleosynthesis" was launched. After five years of successful research related to the experimental investigation of proton- and alpha-induced nuclear reaction for the astrophysical p-process, the project came to an end. In this paper a summary of the research and the most important achievements is given.

  14. An ERC Starting Grant project on p-process nucleosynthesis concluded

    E-Print Network [OSTI]

    Gy Gyürky; Z Halász; T Szücs; G G Kiss; Zs Fülöp

    2015-09-03

    In 2008 a Starting Grant project supported by the European Research Council titled "Nuclear reaction studies relevant to the astrophysical p-process nucleosynthesis" was launched. After five years of successful research related to the experimental investigation of proton- and alpha-induced nuclear reaction for the astrophysical p-process, the project came to an end. In this paper a summary of the research and the most important achievements is given.

  15. Nucleosynthesis in core-collapse supernova explosions triggered by a quark-hadron phase transition

    E-Print Network [OSTI]

    Nobuya Nishimura; Tobias Fischer; Friedrich-Karl Thielemann; Carla Fröhlich; Matthias Hempel; Roger Käppeli; Gabriel Martínez-Pinedo; Thomas Rauscher; Irina Sagert; Christian Winteler

    2012-08-24

    We explore heavy element nucleosynthesis in the explosion of massive stars which are triggered by a quark-hadron phase transition during the early post bounce phase of core-collapse supernovae. The present study is based on general relativistic radiation hydrodynamics simulations with three-flavor Boltzmann neutrino transport in spherical symmetry, which utilize a quark-hadron hybrid equation of state based on the MIT bag model for strange quark matter. The quark-hadron phase transition inside the stellar core forms a shock wave propagating towards the surface of the proto-neutron star. The shock wave results in an explosion and ejects neutron-rich matter which is piled up or accreting on the proto-neutron star. Later, during the cooling phase, the proto-neutron star develops a proton-rich neutrino-driven wind. We present a detailed analysis of the nucleosynthesis outcome in both neutron-rich and proton-rich ejecta and compare our integrated nucleosynthesis with observations of metal poor stars.

  16. NUCLEOSYNTHESIS IN CORE-COLLAPSE SUPERNOVA EXPLOSIONS TRIGGERED BY A QUARK-HADRON PHASE TRANSITION

    SciTech Connect (OSTI)

    Nishimura, Nobuya; Thielemann, Friedrich-Karl; Hempel, Matthias; Kaeppeli, Roger; Rauscher, Thomas; Winteler, Christian [Department of Physics, University of Basel, CH-4056 Basel (Switzerland); Fischer, Tobias; Martinez-Pinedo, Gabriel [GSI, Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Froehlich, Carla [Department of Physics, North Carolina State University, NC 27695 (United States); Sagert, Irina, E-mail: nobuya.nishimura@unibas.ch [Department of Physics and Astronomy, Michigan State University, MI 48824 (United States)

    2012-10-10

    We explore heavy-element nucleosynthesis in the explosion of massive stars that are triggered by a quark-hadron phase transition during the early post-bounce phase of core-collapse supernovae. The present study is based on general-relativistic radiation hydrodynamics simulations with three-flavor Boltzmann neutrino transport in spherical symmetry, which utilize a quark-hadron hybrid equation of state based on the MIT bag model for strange quark matter. The quark-hadron phase transition inside the stellar core forms a shock wave propagating toward the surface of the proto-neutron star. This shock wave results in an explosion and ejects neutron-rich matter from the outer accreted layers of the proto-neutron star. Later, during the cooling phase, the proto-neutron star develops a proton-rich neutrino-driven wind. We present a detailed analysis of the nucleosynthesis outcome in both neutron-rich and proton-rich ejecta and compare our integrated nucleosynthesis with observations of the solar system and metal-poor stars. For our standard scenario, we find that a 'weak' r-process occurs and elements up to the second peak (A {approx} 130) are successfully synthesized. Furthermore, uncertainties in the explosion dynamics could barely allow us to obtain the strong r-process which produces heavier isotopes, including the third peak (A {approx} 195) and actinide elements.

  17. JOURNAL OF THE HISTORY OF MEDICINE AND ALLIED SCIENCES The Author 2006. Published by Oxford University Press. All rights reserved.

    E-Print Network [OSTI]

    Richards, Robert J.

    [ 1 ] JOURNAL OF THE HISTORY OF MEDICINE AND ALLIED SCIENCES © The Author 2006. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals was #12;2 of 2 Journal of the History of Medicine metaphorical and allusive all the way down, and that one

  18. 1995 Oxford University Press 30093017Nucleic Acids Research, 1995, Vol. 23, No. 15 Chemical probe and missing nucleoside analysis of

    E-Print Network [OSTI]

    Tullius, Thomas D.

    © 1995 Oxford University Press 3009­3017Nucleic Acids Research, 1995, Vol. 23, No. 15 ChemicalDepartment of Microbiology, University of Texas, Austin, TX 78712, USA Received March 3, 1995; Revised and Accepted June 19, 1995 ABSTRACT The Flp protein catalyzes a site-specific recombination reaction between

  19. We are using both space-based (Hubble Space Telescope, HST) and ground-based telescopes to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from the rapid neutron capture process, r-process) from the

    E-Print Network [OSTI]

    Cowan, John

    to make extensive studies of Galactic halo stars. These stars contain nucleosynthesis products (from Galactic r-process nucleosynthesis. These in turn will help to identify the characteristics and nature ­ particularly the sites and the astrophysical conditions for their formation EARLY GALACTIC NUCLEOSYNTHESIS

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

    E-Print Network [OSTI]

    Indrani Banerjee; Banibrata Mukhopadhyay

    2013-09-04

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

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

    SciTech Connect (OSTI)

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

    2013-11-20

    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.

  2. r-PROCESS NUCLEOSYNTHESIS IN DYNAMICALLY EJECTED MATTER OF NEUTRON STAR MERGERS

    SciTech Connect (OSTI)

    Goriely, Stephane [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium); Bauswein, Andreas; Janka, Hans-Thomas [Max-Planck-Institut fuer Astrophysik, Postfach 1317, D-85741 Garching (Germany)

    2011-09-10

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

  3. Production of A=6,7 Nuclides in the Alpha + Alpha Reaction and Cosmic Ray Nucleosynthesis

    E-Print Network [OSTI]

    David J. Mercer; Sam M. Austin; J. A. Brown; S. A. Danczyk; S. E. Hirzebruck; J. H. Kelley; T. Suomijarvi; D. A. Roberts; T. P Walker

    2001-04-03

    Cross sections for production of 6He, 6Li, 7Li, and 7Be in the alpha+alpha reaction were measured at bombarding energies of 159.3, 279.6, and 619.8 MeV, and are found to decrease rapidly with increasing energy. These cross sections are essential for the calculation of the rate of nucleosynthesis of the lithium isotopes in the cosmic rays and thereby play a key role in our understanding of the synthesis of Li, Be, and B. The results for 6Li differ significantly from the tabulated values commonly used in cosmic-ray production calculations and lead to lower production of 6Li.

  4. r-Process Nucleosynthesis in Shocked Surface Layers of O-Ne-Mg Cores

    E-Print Network [OSTI]

    H. Ning; Y. -Z. Qian; B. S. Meyer

    2007-08-13

    We demonstrate that rapid expansion of the shocked surface layers of an O-Ne-Mg core following its collapse can result in r-process nucleosynthesis. As the supernova shock accelerates through these layers, it makes them expand so rapidly that free nucleons remain in disequilibrium with alpha-particles throughout most of the expansion. This allows heavy r-process isotopes including the actinides to form in spite of the very low initial neutron excess of the matter. We estimate that yields of heavy r-process nuclei from this site may be sufficient to explain the Galactic inventory of these isotopes.

  5. Beta Decays of Isotones with Neutron Magic Number of N=126 and R-process Nucleosynthesis

    E-Print Network [OSTI]

    Toshio Suzuki; Takashi Yoshida; Toshitaka Kajino; Takaharu Otsuka

    2011-12-16

    Beta decays of the isotones with N=126 are studied by shell model calculations taking into account both the Gamow-Teller (GT) and first-forbidden (FF) transitions. The FF transitions are found to be important to reduce the half-lives, by nearly twice to several times, from those by the GT contributions only. Possible implications of the short half-lives of the waiting point nuclei on the r-process nucleosynthesis during the supernova explosions are discussed. A slight shift of the third peak of the element abundances in the r-process toward higher mass region is found.

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

    SciTech Connect (OSTI)

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

    1990-09-01

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

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

    SciTech Connect (OSTI)

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

    2014-05-09

    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.

  8. The Effects of Variations in Nuclear Processes on Type I X-Ray Burst Nucleosynthesis

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

    2008-02-20

    Type I X-ray bursts are violent stellar events that take place on the H/He-rich envelopes of accreting neutron stars. We have investigated the role played by uncertainties in nuclear processes on the nucleosynthesis accompanying these explosive phenomena. Two different approaches have been adopted, in the framework of post-processing calculations. In the first one, nuclear rates are varied individually within uncertainties. Ten different models, covering the characteristic parameter space for these stellar events, have been considered. The second, somewhat complementary approach involves a Monte Carlo code in which all nuclear rates are randomly varied within uncertainty limits simultaneously. All in all, about 50,000 post-processing calculations, with a network containing 606 nuclides (H to 113Xe) and more than 3500 nuclear processes, have been performed in this work. A brief comparison between both procedures is outlined together with an overall account of the key nuclear reactions whose uncertainties have the largest impact in our X-ray burst nucleosynthesis studies.

  9. 28/07/2010 10:43Evolution's parent trap -University of Oxford Page 1 of 2http://www.ox.ac.uk/media/science_blog/100728.html

    E-Print Network [OSTI]

    Gardner, Andy

    28/07/2010 10:43Evolution's parent trap - University of Oxford Page 1 of 2http://www.ox.ac.uk/media/science_blog of these traits are related. I asked Andy about the costs and benefits of intensive parenting: OxSciBlog: What leave the #12;28/07/2010 10:43Evolution's parent trap - University of Oxford Page 2 of 2http://www.ox.ac.uk/media/science_blog

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

    E-Print Network [OSTI]

    Asger G. Gasanalizade; Ramin A. Hasanalizade

    2015-02-20

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

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

    E-Print Network [OSTI]

    Lattanzio, John

    nucleosynthesis occurring in the helium shell is the production of alpha ele- ments (via helium burning) as well process- es. There are two primary sites for these processes: the helium burning shell and the hydrogen burning shell. The reason that these are of more interest in an AGB star is that the helium shell shows

  12. Explosive Nucleosynthesis of Weak r-Process Elements in Extremely Metal-Poor Core-Collapse Supernovae

    E-Print Network [OSTI]

    N. Izutani; H. Umeda; N. Tominaga

    2008-10-31

    There have been attempts to fit the abundance patterns of extremely metal-poor stars with supernova nucleosynthesis models for the lighter elements than Zn. On the other hand, observations have revealed that the presence of EMP stars with peculiarly high ratio of "weak r-process elements" Sr, Y and Zr. Although several possible processes were suggested for the origin of these elements, the complete solution for reproducing those ratios is not found yet. In order to reproduce the abundance patterns of such stars, we investigate a model with neutron rich matter ejection from the inner region of the conventional mass-cut. We find that explosive nucleosynthesis in a high energy supernova (or "hypernova") can reproduce the high abundances of Sr, Y and Zr but that the enhancements of Sr, Y and Zr are not achieved by nucleosynthesis in a normal supernova. Our results imply that, if these elements are ejected from a normal supernova, nucleosynthesis in higher entropy flow than that of the supernova shock is required.

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

    E-Print Network [OSTI]

    Winkel, Matthias

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

  14. General relativistic effects in the neutrino-driven wind and r-process nucleosynthesis

    E-Print Network [OSTI]

    Christian Y. Cardall; George M. Fuller

    1997-01-22

    We discuss general relativistic effects in the steady-state neutrino-driven ``wind'' which may arise from nascent neutron stars. In particular, we generalize previous analytic estimates of the entropy per baryon $S$, the mass outflow rate $\\dot M$, and the dynamical expansion time scale $\\tau_{dyn}$. We show that $S$ increases and $\\tau_{dyn}$ decreases with increasing values of the mass-to-radius ratio describing the supernova core. Both of these trends indicate that a more compact core will lead to a higher number of neutrons per iron peak seed nucleus. Such an enhancement in the neutron-to-seed ratio may be required for successful r-process nucleosynthesis in neutrino-heated supernova ejecta.

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

    SciTech Connect (OSTI)

    Nishimura, Shunji; Collaboration: RIBF Decay Collaboration

    2012-11-12

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

  16. Toward precision mass measurements of neutron-rich nuclei relevant to $r$-process nucleosynthesis

    E-Print Network [OSTI]

    B. H. Sun; Yu. A. Litvinov; I. Tanihata; Y. H. Zhang

    2015-08-04

    The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies.\\ Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron.\\ Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies.\\ In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in $r$-process calculations.\\ We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples.\\ For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of $r$-process nuclides.

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

    E-Print Network [OSTI]

    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

    2006-01-11

    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.

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

    SciTech Connect (OSTI)

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

    2014-03-01

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

  19. Sensitivity studies for r-process nucleosynthesis in three astrophysical scenarios

    E-Print Network [OSTI]

    R. Surman; M. Mumpower; J. Cass; I. Bentley; A. Aprahamian; G. C. McLaughlin

    2013-08-31

    In rapid neutron capture, or r-process, nucleosynthesis, heavy elements are built up via a sequence of neutron captures and beta decays that involves thousands of nuclei far from stability. Though we understand the basics of how the r-process proceeds, its astrophysical site is still not conclusively known. The nuclear network simulations we use to test potential astrophysical scenarios require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for all of the nuclei on the neutron-rich side of the nuclear chart, from the valley of stability to the neutron drip line. Here we discuss recent sensitivity studies that aim to determine which individual pieces of nuclear data are the most crucial for r-process calculations. We consider three types of astrophysical scenarios: a traditional hot r-process, a cold r-process in which the temperature and density drop rapidly, and a neutron star merger trajectory.

  20. The sensitivity of r-process nucleosynthesis to the properties of neutron-rich nuclei

    E-Print Network [OSTI]

    R. Surman; M. Mumpower; J. Cass; A. Aprahamian

    2013-08-31

    About half of the heavy elements in the Solar System were created by rapid neutron capture, or r-process, nucleosynthesis. In the r-process, heavy elements are built up via a sequence of neutron captures and beta decays in which an intense neutron flux pushes material out towards the neutron drip line. The nuclear network simulations used to test potential astrophysical scenarios for the r-process therefore require nuclear physics data (masses, beta decay lifetimes, neutron capture rates, fission probabilities) for thousands of nuclei far from stability. Only a small fraction of this data has been experimentally measured. Here we discuss recent sensitivity studies that aim to determine the nuclei whose properties are most crucial for r-process calculations.

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

    SciTech Connect (OSTI)

    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)

    2012-11-12

    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.

  2. Toward precision mass measurements of neutron-rich nuclei relevant to $r$-process nucleosynthesis

    E-Print Network [OSTI]

    Sun, B H; Tanihata, I; Zhang, Y H

    2015-01-01

    The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies.\\ Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron.\\ Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies.\\ In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in $r$-process calculations.\\ We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples.\\ For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of $r$-process nuclides.

  3. r-Process Nucleosynthesis in Hot Accretion Disk Flows from Black Hole - Neutron Star Mergers

    E-Print Network [OSTI]

    R. Surman; G. C. McLaughlin; M. Ruffert; H. -Th. Janka; W. R. Hix

    2008-06-25

    We consider hot accretion disk outflows from black hole - neutron star mergers in the context of the nucleosynthesis they produce. We begin with a three dimensional numerical model of a black hole - neutron star merger and calculate the neutrino and antineutrino fluxes emitted from the resulting accretion disk. We then follow the element synthesis in material outflowing the disk along parameterized trajectories. We find that at least a weak r-process is produced, and in some cases a main r-process as well. The neutron-rich conditions required for this production of r-process nuclei stem directly from the interactions of the neutrinos emitted by the disk with the free neutrons and protons in the outflow.

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

    E-Print Network [OSTI]

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

    2006-09-28

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

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

    E-Print Network [OSTI]

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

    1998-07-06

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

  6. Nucleosynthesis in helium-enriched asymptotic giant branch models: Implications for heavy element enrichment in ? Centauri

    SciTech Connect (OSTI)

    Karakas, Amanda I.; Marino, Anna F.; Nataf, David M., E-mail: Amanda.Karakas@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia)

    2014-03-20

    We investigate the effect of helium enrichment on the evolution and nucleosynthesis of low-mass asymptotic giant branch (AGB) stars of 1.7 M {sub ?} and 2.36 M {sub ?} with a metallicity of Z = 0.0006 ([Fe/H] ?–1.4). We calculate evolutionary sequences with the primordial helium abundance (Y = 0.24) and with helium-enriched compositions (Y = 0.30, 0.35, 0.40). For comparison, we calculate models of the same mass but at a lower metallicity Z = 0.0003 ([Fe/H] ?–1.8) with Y = 0.24. Post-processing nucleosynthesis calculations are performed on each of the evolutionary sequences to determine the production of elements from hydrogen to bismuth. Elemental surface abundance predictions and stellar yields are presented for each model. The models with enriched helium have shorter main sequence and AGB lifetimes, and they enter the AGB with a more massive hydrogen-exhausted core than the primordial helium model. The main consequences are as follows: (1) low-mass AGB models with enhanced helium will evolve more than twice as fast, giving them the chance to contribute sooner to the chemical evolution of the forming globular clusters, and (2) the stellar yields will be strongly reduced relative to their primordial helium counterparts. An increase of ?Y = 0.10 at a given mass decreases the yields of carbon by up to ?60% and of fluorine by up to 80%; it also decreases the yields of the s-process elements barium and lanthanum by ?45%. While the yields of first s-process peak elements strontium, yttrium, and zirconium decrease by up to 50%, the yields of rubidium either do not change or increase.

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

    SciTech Connect (OSTI)

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

    2013-05-20

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

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

    E-Print Network [OSTI]

    McDowell, Sean H.

    2011-01-01

    studied writers also receive attention in these volumes, either under the auspices of a speci?c genre or, in the case of the Cambridge Companion series, of period or thematic groupings (e.g., ?e Cambridge Companion to Writing of the English Revolution... the chosen literary text. Within Milton studies, a prime example is the Cambridge Univer- sity Press volume, Milton in Context, published in 2010 and edited by Stephen B. Dobranski. is book can be seen as the nearest competitor of ?e Oxford Handbook...

  9. Core-Collapse Very Massive Stars: Evolution, Explosion, and Nucleosynthesis of Population III 500 -- 1000 $M_{\\odot}$ Stars

    E-Print Network [OSTI]

    T. Ohkubo; H. Umeda; K. Maeda; K. Nomoto; T. Suzuki; S. Tsuruta; M. J. Rees

    2006-05-09

    We calculate evolution, collapse, explosion, and nucleosynthesis of Population III very-massive stars with 500$M_{\\odot}$ and 1000$M_{\\odot}$. Presupernova evolution is calculated in spherical symmetry. Collapse and explosion are calculated by a two-dimensional code, based on the bipolar jet models. We compare the results of nucleosynthesis with the abundance patterns of intracluster matter, hot gases in M82, and extremely metal-poor stars in the Galactic halo. It was found that both 500$M_{\\odot}$ and 1000$M_{\\odot}$ models enter the region of pair-instability but continue to undergo core collapse. In the presupernova stage, silicon burning regions occupy a large fraction, more than 20% of the total mass. For moderately aspherical explosions, the patterns of nucleosynthesis match the observational data of both intracluster medium and M82. Our results suggest that explosions of Population III core-collapse very-massive stars contribute significantly to the chemical evolution of gases in clusters of galaxies. For Galactic halo stars, our [O/Fe] ratios are smaller than the observational abundances. However, our proposed scenario is naturally consistent with this outcome. The final black hole masses are $\\sim 230M_{\\odot}$ and $\\sim 500M_{\\odot}$ for the $500M_{\\odot}$ and 1000$M_{\\odot}$ models, respectively. This result may support the view that Population III very massive stars are responsible for the origin of intermediate mass black holes which were recently reported to be discovered.

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

    E-Print Network [OSTI]

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

    2013-06-25

    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.

  11. SYSTEMATICS OF DYNAMICAL MASS EJECTION, NUCLEOSYNTHESIS, AND RADIOACTIVELY POWERED ELECTROMAGNETIC SIGNALS FROM NEUTRON-STAR MERGERS

    SciTech Connect (OSTI)

    Bauswein, A.; Janka, H.-T. [Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Goriely, S. [Institut d'Astronomie et d'Astrophysique, Universite Libre de Bruxelles, C.P. 226, B-1050 Brussels (Belgium)

    2013-08-10

    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{sub 1.35} of a 1.35 M{sub Sun} NS. NSs with smaller R{sub 1.35} (''soft'' EOS) eject systematically higher masses. These range from {approx}10{sup -3} M{sub Sun} to {approx}10{sup -2} M{sub Sun} for 1.35-1.35 M{sub Sun} binaries and from {approx}5 Multiplication-Sign 10{sup -3} M{sub Sun} to {approx}2 Multiplication-Sign 10{sup -2} M{sub Sun} for 1.2-1.5 M{sub Sun} systems (with kinetic energies between {approx}5 Multiplication-Sign 10{sup 49} erg and 10{sup 51} erg). Correspondingly, the bolometric peak luminosities of the optical transients of symmetric (asymmetric) mergers vary between 3 Multiplication-Sign 10{sup 41} erg s{sup -1} and 14 Multiplication-Sign 10{sup 41} erg s{sup -1} (9 Multiplication-Sign 10{sup 41} erg s{sup -1} and 14.5 Multiplication-Sign 10{sup 41} erg s{sup -1}) on timescales between {approx}2 hr and {approx}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 Multiplication-Sign 10{sup -5} yr{sup -1} (4 Multiplication-Sign 10{sup -4} yr{sup -1}) for a soft (stiff) NS EOS, if NS mergers are the main source of heavy r-nuclei. The production ratio of radioactive {sup 232}Th to {sup 238}U 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.

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

    E-Print Network [OSTI]

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

    1998-12-11

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

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

    E-Print Network [OSTI]

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

    2001-04-26

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

  14. The r-process of stellar nucleosynthesis: Astrophysics and nuclear physics achievements and mysteries

    E-Print Network [OSTI]

    M. Arnould; S. Goriely; K. Takahashi

    2007-05-31

    The r-process, or the rapid neutron-capture process, of stellar nucleosynthesis is called for to explain the production of the stable (and some long-lived radioactive) neutron-rich nuclides heavier than iron that are observed in stars of various metallicities, as well as in the solar system. A very large amount of nuclear information is necessary in order to model the r-process. This concerns the static characteristics of a large variety of light to heavy nuclei between the valley of stability and the vicinity of the neutron-drip line, as well as their beta-decay branches or their reactivity. The enormously challenging experimental and theoretical task imposed by all these requirements is reviewed, and the state-of-the-art development in the field is presented. Nuclear-physics-based and astrophysics-free r-process models of different levels of sophistication have been constructed over the years. We review their merits and their shortcomings. For long, the core collapse supernova of massive stars has been envisioned as the privileged r-process location. We present a brief summary of the one- or multidimensional spherical or non-spherical explosion simulations available to-date. Their predictions are confronted with the requirements imposed to obtain an r-process. The possibility of r-nuclide synthesis during the decompression of the matter of neutron stars following their merging is also discussed.

  15. Deep-Ocean Crusts as Telescopes: Using Live Radioisotopes to Probe Supernova Nucleosynthesis

    E-Print Network [OSTI]

    Brian D. Fields; Kathrin A. Hochmuth; John Ellis

    2004-10-22

    Live 60Fe has recently been detected in a deep-ocean ferromanganese crust, isolated in layers dating from about 3 Myr ago. Since 60Fe has a mean life of 2.2 Myr, a near-Earth supernova is the only likely source for such a signal, and we explore here the consequences of a supernova origin. We combine the 60Fe data with several supernova nucleosynthesis models to calculate the supernova distance as a function of progenitor mass, finding an allowed range of 15-120 pc. We also predict the signals expected for several other radioisotopes, which are independent of the supernova distance. Species likely to be present near or above background levels are 10Be, 26Al, 53Mn, 182Hf and 244Pu. Of these, 182Hf and 244Pu are nearly background-free, presenting the best opportunities to provide strong confirmation of the supernova origin of the 60Fe signal, and to demonstrate that at least some supernovae are the source for the r-process. The accuracies of our predictions are hampered by large uncertainties in the predicted 60Fe yields for supernovae of different masses, so the new crust data motivate a redoubled theoretical attack on this problem.

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

    E-Print Network [OSTI]

    A. Arcones; G. Martinez-Pinedo

    2010-12-14

    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.

  17. Neutrino-driven winds in the aftermath of a neutron star merger: nucleosynthesis and electromagnetic transients

    E-Print Network [OSTI]

    Dirk Martin; Albino Perego; Almudena Arcones; Friedrich-Karl Thielemann; Oleg Korobkin; Stephan Rosswog

    2015-09-24

    We present a comprehensive nucleosynthesis study of the neutrino-driven wind in the aftermath of a binary neutron star merger. Our focus is the initial remnant phase when a massive central neutron star is present. Using tracers from a recent hydrodynamical simulation, we determine total masses and integrated abundances to characterize the composition of unbound matter. We find that the nucleosynthetic yields depend sensitively on both the life time of the massive neutron star and the polar angle. Matter in excess of up to $9 \\cdot 10^{-3} M_\\odot$ becomes unbound until $\\sim 200~{\\rm ms}$. Due to electron fractions of $Y_{\\rm e} \\approx 0.2 - 0.4$ mainly nuclei with mass numbers $A < 130$ are synthesized, complementing the yields from the earlier dynamic ejecta. Mixing scenarios with these two types of ejecta can explain the abundance pattern in r-process enriched metal-poor stars. Additionally, we calculate heating rates for the decay of the freshly produced radioactive isotopes. The resulting light curve peaks in the blue band after about $4~{\\rm h}$. Furthermore, high opacities due to heavy r-process nuclei in the dynamic ejecta lead to a second peak in the infrared after $3-4~{\\rm d}$.

  18. Constraints on Lepton Asymmetry from Nucleosynthesis in a Linearly Coasting Cosmology

    E-Print Network [OSTI]

    Parminder Singh; Daksh Lohiya

    2015-05-30

    We study the effect of neutrino degeneracy on primordial nucleosynthesis in a universe in which the cosmological scale factor evolves linearly with time. The degeneracy parameter of electron type neutrinos ($\\xi_e$) determines the $n/p$ (neutron to proton) ratio, which in turn determines the abundance of $^4$He in a manner quite distinct from the Standard Scenario. The observed abundances of $^4$He, $\\mathrm{Y}_P$=0.254$\\pm$0.003, and the minimum metallicity that is essential for fragmentation and cooling processes in star forming prestellar gas clouds (Z = Z$_{cr}$ = 10$^{-6}$Z$_\\odot$), constrain the baryon to photon ratio, $\\eta_B$=(3.927$\\pm$0.292)10$^{-9}$, corresponding to a baryonic matter density, $\\Omega_B$=0.263$\\pm$ 0.026 and $\\xi_e$=-2.165$\\pm$0.171. This closes the dynamic mass estimates of matter in the universe by baryons alone. Useful byproducts are the threshold X(CNO) abundances required to trigger the CNO cycle in the observed low metallicity stars in the universe.

  19. Theoretical neutron-capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region

    E-Print Network [OSTI]

    Rauscher, T; Kratz, K -L; Balogh, W; Oberhummer, H

    2015-01-01

    We calculate neutron capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region, namely for the isotopes $^{40-44}$S, $^{46-50}$Ar, $^{56-66}$Ti, $^{62-68}$Cr, and $^{72-76}$Fe. While previously only cross sections resulting from the compound nucleus reaction mechanism (Hauser-Feshbach) have been considered, we recalculate not only that contribution to the cross section but also include direct capture on even-even nuclei. The level schemes, which are of utmost importance in the direct capture calculations, are taken from quasi-particle states obtained with a folded-Yukawa potential and Lipkin-Nogami pairing. Most recent deformation values derived from experimental data on $\\beta$-decay half lives are used where available. Due to the consideration of direct capture, the capture rates are enhanced and the "turning points" in the r-process path are shifted to slightly higher mass numbers. We also discuss the sensitivity of the direct capture cross sections on the assumed deformation.

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

    SciTech Connect (OSTI)

    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)

    2014-05-02

    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.

  1. Theoretical neutron-capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region

    E-Print Network [OSTI]

    T. Rauscher; W. Böhmer; K. -L. Kratz; W. Balogh; H. Oberhummer

    2015-04-17

    We calculate neutron capture cross sections for r-process nucleosynthesis in the $^{48}$Ca region, namely for the isotopes $^{40-44}$S, $^{46-50}$Ar, $^{56-66}$Ti, $^{62-68}$Cr, and $^{72-76}$Fe. While previously only cross sections resulting from the compound nucleus reaction mechanism (Hauser-Feshbach) have been considered, we recalculate not only that contribution to the cross section but also include direct capture on even-even nuclei. The level schemes, which are of utmost importance in the direct capture calculations, are taken from quasi-particle states obtained with a folded-Yukawa potential and Lipkin-Nogami pairing. Most recent deformation values derived from experimental data on $\\beta$-decay half lives are used where available. Due to the consideration of direct capture, the capture rates are enhanced and the "turning points" in the r-process path are shifted to slightly higher mass numbers. We also discuss the sensitivity of the direct capture cross sections on the assumed deformation.

  2. New Stellar $(n,?)$ Cross Sections and The "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars"

    E-Print Network [OSTI]

    I. Dillmann; R. Plag; C. Domingo-Pardo; M. Heil; F. Käppeler; T. Rauscher; F. -K. Thielemann

    2008-06-12

    Since April 2005 a regularly updated stellar neutron cross section compilation is available online at http://nuclear-astrophysics.fzk.de/kadonis. This online-database is called the "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars" project and is based on the previous Bao et al. compilation from the year 2000. The present version \\textsc{KADoNiS} v0.2 (January 2007) includes recommended cross sections for 280 isotopes between $^{1}$H and $^{210}$Po and 75 semi-empirical estimates for isotopes without experimental information. Concerning stellar $(n,\\gamma)$ cross sections of the 32 stable, proton-rich isotopes produced by the $p$ process experimental information is only available for 20 isotopes, but 9 of them have rather large uncertainties of $\\geq$9%. The first part of a systematic study of stellar $(n,\\gamma)$ cross sections of the $p$-process isotopes $^{74}$Se, $^{84}$Sr, $^{102}$Pd, $^{120}$Te, $^{130}$Ba, $^{132}$Ba, $^{156}$Dy, and $^{174}$Hf is presented. In another application \\textsc{KADoNiS} v0.2 was used for an modification of a reaction library of Basel university. With this modified library $p$-process network calculations were carried out and compared to previous results.

  3. Evolution and nucleosynthesis of helium-rich asymptotic giant branch models

    E-Print Network [OSTI]

    Shingles, Luke J; Karakas, Amanda I; Stancliffe, Richard J; Lattanzio, John C; Lugaro, Maria

    2015-01-01

    There is now strong evidence that some stars have been born with He mass fractions as high as $Y \\approx 0.40$ (e.g., in $\\omega$ Centauri). However, the advanced evolution, chemical yields, and final fates of He-rich stars are largely unexplored. We investigate the consequences of He-enhancement on the evolution and nucleosynthesis of intermediate-mass asymptotic giant branch (AGB) models of 3, 4, 5, and 6 M$_\\odot$ with a metallicity of $Z = 0.0006$ ([Fe/H] $\\approx -1.4$). We compare models with He-enhanced compositions ($Y=0.30, 0.35, 0.40$) to those with primordial He ($Y=0.24$). We find that the minimum initial mass for C burning and super-AGB stars with CO(Ne) or ONe cores decreases from above our highest mass of 6 M$_\\odot$ to $\\sim$ 4-5 M$_\\odot$ with $Y=0.40$. We also model the production of trans-Fe elements via the slow neutron-capture process (s-process). He-enhancement substantially reduces the third dredge-up efficiency and the stellar yields of s-process elements (e.g., 90% less Ba for 6 M$_\\o...

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

    E-Print Network [OSTI]

    M. Kaplinghat; M. S. Turner

    2000-11-14

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

  5. Solving the discrepancy among the light elements abundances and WMAP

    E-Print Network [OSTI]

    Kazuhide Ichikawa; Masahiro Kawasaki; Fuminobu Takahashi

    2004-06-09

    Within the standard big bang nucleosynthesis (BBN) and cosmic microwave background (CMB) framework, the baryon density measured by the Wilkinson Microwave Anisotropy Probe (WMAP) or the primordial D abundance is much higher than the one measured by the $^4$He or $^7$Li abundances. To solve the discrepancy, we propose a scenario in which additional baryons appear after BBN. We show that simply adding the baryons can not be a solution but the existence of a large lepton asymmetry before BBN makes the scenario successful. These extra baryons and leptons, in addition to the initial baryons which exist before the BBN, can be all produced from $Q$-balls.

  6. Thermal relics in cosmology with bulk viscosity

    E-Print Network [OSTI]

    A. Iorio; G. Lambiase

    2014-11-28

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

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

    SciTech Connect (OSTI)

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

    2014-05-02

    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.

  8. Long-lived stop at the LHC with or without R-parity

    SciTech Connect (OSTI)

    Covi, L.; Dradi, F., E-mail: laura.covi@theorie.physik.uni-goettingen.de, E-mail: federico.dradi@theorie.physik.uni-goettingen.de [Institut für Theoretische Physik, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany)

    2014-10-01

    We consider scenarios of gravitino LSP and DM with stop NLSP both within R-parity conserving and R-parity violating supersymmetry (RPC and RPV SUSY, respectively). We discuss cosmological bounds from Big Bang Nucleosynthesis (BBN) and the gravitino abundance and then concentrate on the signals of long-lived stops at the LHC as displaced vertices or metastable particles. Finally we discuss how to distinguish R-parity conserving and R-parity breaking stop decays if they happen within the detector and how to suppress SM backgrounds.

  9. Probing lepton asymmetry with 21 cm fluctuations

    SciTech Connect (OSTI)

    Kohri, Kazunori; Oyama, Yoshihiko [The Graduate University for Advanced Studies (Sokendai), 1-1 Oho, Tsukuba 305-0801 (Japan); Sekiguchi, Toyokazu [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 (Japan); Takahashi, Tomo, E-mail: kohri@post.kek.jp, E-mail: oyamayo@post.kek.jp, E-mail: toyokazu.sekiguchi@helsinki.fi, E-mail: tomot@cc.saga-u.ac.jp [Department of Physics, Saga University, Saga 840-8502 (Japan)

    2014-09-01

    We investigate the issue of how accurately we can constrain the lepton number asymmetry ?{sub ?}=?{sub ?}/T{sub ?} in the Universe by using future observations of 21 cm line fluctuations and cosmic microwave background (CMB). We find that combinations of the 21 cm line and the CMB observations can constrain the lepton asymmetry better than big-bang nucleosynthesis (BBN). Additionally, we also discuss constraints on ?{sub ?} in the presence of some extra radiation, and show that the 21 cm line observations can substantially improve the constraints obtained by CMB alone, and allow us to distinguish the effects of the lepton asymmetry from the ones of extra radiation.

  10. Environmental Sustainability Policy The University of Oxford has over 22,000 students. The University's functional estate covers 600,000 m2

    E-Print Network [OSTI]

    Environmental Sustainability Policy The University of Oxford has over 22,000 students by the Environmental Sustainability team. Through its activities and actions the University recognises it impacts areas through which environmental sustainability shall be approached. These are; Energy and carbon

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

    E-Print Network [OSTI]

    Langerhans, Brian

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

  12. Invited Keynote: Harnad, S (2102) Digital Research: How and Why the RCUK Open Access Policy Needs to Be Revised. Digital Research 2012. Tuesday, September 12, Oxford.

    E-Print Network [OSTI]

    Harnad, Stevan

    2102-01-01

    Invited Keynote: Harnad, S (2102) Digital Research: How and Why the RCUK Open Access Policy Needs to Be Revised. Digital Research 2012. Tuesday, September 12, Oxford. HOW AND WHY RCUK OPEN ACCESS POLICY NEEDS in the global movement toward Open Access (OA) to research but very recently its leadership has been derailed

  13. The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com Tree Physiology 00, 112

    E-Print Network [OSTI]

    Clark, James S.

    © The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com Tree Physiology 00, 1­12 doi:10.1093/treephys/tps114 Hydraulic hydraulic model with measurements of sap flux (J) at breast height and the base of the live crown for 26

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

    E-Print Network [OSTI]

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

  15. Journal of Refugee Studies Vol. 19, No. 2 The Author [2006]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

    E-Print Network [OSTI]

    Scharfstein, Daniel

    Journal of Refugee Studies Vol. 19, No. 2 Ó The Author [2006]. Published by Oxford University Press.1093/jrs/fej019 Advance Access published on 31 March 2006 Protracted Refugee Situations: Parallel Health 1 RABBIN M . D RABE 2 1 Center for Refugee and Disaster Response, Department of International Health

  16. 8/29/2014 The Nutrition Transition -Geography-Oxford Bibliographies -http://www.oxfordbibliographies.com/view/document/obo-9780199874002/obo-9780199874002-0078.xml 1/17

    E-Print Network [OSTI]

    Lopez-Carr, David

    8/29/2014 The Nutrition Transition - Geography- Oxford Bibliographies - http to provide a broad introduction to the theory, but we believe that geography is a particularly relevant of the transition, while a nearby luxury home may be in stage 5. Geography and geographical methods sensitive

  17. Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity

    SciTech Connect (OSTI)

    Fishlock, Cherie K.; Karakas, Amanda I.; Yong, David [Research School of Astronomy and Astrophysics, Australian National University, Canberra ACT 2611 (Australia); Lugaro, Maria, E-mail: cherie.fishlock@anu.edu.au, E-mail: amanda.karakas@anu.edu.au, E-mail: david.yong@anu.edu.au, E-mail: maria.lugaro@monash.edu [Monash Centre for Astrophysics, Monash University, Clayton VIC 3800 (Australia)

    2014-12-10

    We present stellar evolutionary tracks and nucleosynthetic predictions for a grid of stellar models of low- and intermediate-mass asymptotic giant branch (AGB) stars at Z = 0.001 ([Fe/H] =–1.2). The models cover an initial mass range from 1 M {sub ?} to 7 M {sub ?}. Final surface abundances and stellar yields are calculated for all elements from hydrogen to bismuth as well as isotopes up to the iron group. We present the first study of neutron-capture nucleosynthesis in intermediate-mass AGB models, including a super-AGB model, of [Fe/H] = –1.2. We examine in detail a low-mass AGB model of 2 M {sub ?} where the {sup 13}C(?,n){sup 16}O reaction is the main source of neutrons. We also examine an intermediate-mass AGB model of 5 M {sub ?} where intershell temperatures are high enough to activate the {sup 22}Ne neutron source, which produces high neutron densities up to ?10{sup 14} n cm{sup –3}. Hot bottom burning is activated in models with M ? 3 M {sub ?}. With the 3 M {sub ?} model, we investigate the effect of varying the extent in mass of the region where protons are mixed from the envelope into the intershell at the deepest extent of each third dredge-up. We compare the results of the low-mass models to three post-AGB stars with a metallicity of [Fe/H] ? – 1.2. The composition is a good match to the predicted neutron-capture abundances except for Pb and we confirm that the observed Pb abundances are lower than what is calculated by AGB models.

  18. EVOLUTION, NUCLEOSYNTHESIS, AND YIELDS OF LOW-MASS ASYMPTOTIC GIANT BRANCH STARS AT DIFFERENT METALLICITIES. II. THE FRUITY DATABASE

    SciTech Connect (OSTI)

    Cristallo, S.; Dominguez, I.; Abia, C. [Departamento de Fisica Teorica y del Cosmos, Universidad de Granada, 18071 Granada (Spain); Piersanti, L.; Straniero, O.; Gallino, R.; Di Rico, G.; Quintini, M. [INAF-Osservatorio Astronomico di Collurania, 64100 Teramo (Italy); Bisterzo, S. [Dipartimento di Fisica Generale, Universita di Torino, 10125 Torino (Italy)

    2011-12-01

    By using updated stellar low-mass stars models, we systematically investigate the nucleosynthesis processes occurring in asymptotic giant branch (AGB) stars. In this paper, we present a database dedicated to the nucleosynthesis of AGB stars: FRANEC Repository of Updated Isotopic Tables and Yields (FRUITY). An interactive Web-based interface allows users to freely download the full (from H to Bi) isotopic composition, as it changes after each third dredge-up (TDU) episode and the stellar yields the models produce. A first set of AGB models, having masses in the range 1.5 {<=}M/M{sub Sun} {<=} 3.0 and metallicities 1 Multiplication-Sign 10{sup -3} {<=} Z {<=} 2 Multiplication-Sign 10{sup -2}, is discussed. For each model, a detailed description of the physical and the chemical evolution is provided. In particular, we illustrate the details of the s-process and we evaluate the theoretical uncertainties due to the parameterization adopted to model convection and mass loss. The resulting nucleosynthesis scenario is checked by comparing the theoretical [hs/ls] and [Pb/hs] ratios to those obtained from the available abundance analysis of s-enhanced stars. On the average, the variation with the metallicity of these spectroscopic indexes is well reproduced by theoretical models, although the predicted spread at a given metallicity is substantially smaller than the observed one. Possible explanations for such a difference are briefly discussed. An independent check of the TDU efficiency is provided by the C-stars luminosity function. Consequently, theoretical C-stars luminosity functions for the Galactic disk and the Magellanic Clouds have been derived. We generally find good agreement with observations.

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

    E-Print Network [OSTI]

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

    2001-07-19

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

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

    E-Print Network [OSTI]

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

    2014-12-22

    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.

  1. 23/02/2009 16:02Slime cities & bacteria signals -University of Oxford Page 1 of 2http://www.ox.ac.uk/media/science_blog/090223.html

    E-Print Network [OSTI]

    West, Stuart

    23/02/2009 16:02Slime cities & bacteria signals - University of Oxford Page 1 of 2http://www.ox.ac.uk/media/science_blog in humans: OxSciBlog: What are the social interactions that go on between bacterial cells? Stuart West - University of Oxford Page 2 of 2http://www.ox.ac.uk/media/science_blog/090223.html signalling molecules

  2. Asymmetric dark matter annihilation as a test of non-standard cosmologies

    SciTech Connect (OSTI)

    Gelmini, Graciela B.; Huh, Ji-Haeng; Rehagen, Thomas, E-mail: gelmini@physics.ucla.edu, E-mail: jhhuh@physics.ucla.edu, E-mail: trehagen@physics.ucla.edu [Department of Physics and Astronomy, University of California, Los Angeles (UCLA), 475 Portola Plaza, Los Angeles, CA 90095 (United States)

    2013-08-01

    We show that the relic abundance of the minority component of asymmetric dark matter can be very sensitive to the expansion rate of the Universe and the temperature of transition between a non-standard pre-Big Bang Nucleosynthesis cosmological phase and the standard radiation dominated phase, if chemical decoupling happens before this transition. In particular, because the annihilation cross section of asymmetric dark matter is typically larger than that of symmetric dark matter in the standard cosmology, the decrease in relic density of the minority component in non-standard cosmologies with respect to the majority component may be compensated by the increase in annihilation cross section, so that the annihilation rate at present of asymmetric dark matter, contrary to general belief, could be larger than that of symmetric dark matter in the standard cosmology. Thus, if the annihilation cross section of the asymmetric dark matter candidate is known, the annihilation rate at present, if detectable, could be used to test the Universe before Big Bang Nucleosynthesis, an epoch from which we do not yet have any data.

  3. Precision Mass Measurements of 129-131Cd and Their Impact on Stellar Nucleosynthesis via the Rapid Neutron Capture Process

    E-Print Network [OSTI]

    D. Atanasov; P. Ascher; K. Blaum; R. B. Cakirli; T. E. Cocolios; S. George; F. Herfurth; D. Kisler; M. Kowalska; S. Kreim; Yu. A. Litvinov; D. Lunney; V. Manea; D. Neidherr; M. Rosenbusch; L. Schweikhard; A. Welker; F. Wienholtz; R. N. Wolf; K. Zuber

    2015-12-17

    Masses adjacent to the classical waiting-point nuclide 130Cd have been measured by using the Penning- trap spectrometer ISOLTRAP at ISOLDE/CERN. We find a significant deviation of over 400 keV from earlier values evaluated by using nuclear beta-decay data. The new measurements show the reduction of the N = 82 shell gap below the doubly magic 132Sn. The nucleosynthesis associated with the ejected wind from type-II supernovae as well as from compact object binary mergers is studied, by using state-of-the-art hydrodynamic simulations. We find a consistent and direct impact of the newly measured masses on the calculated abundances in the A = 128 - 132 region and a reduction of the uncertainties from the precision mass input data.

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

    E-Print Network [OSTI]

    Anuj Parikh; Jordi Jose; Fermin Moreno; Christian Iliadis

    2008-06-18

    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.

  5. R-Process Nucleosynthesis In Neutrino-Driven Winds From A Typical Neutron Star With M = 1.4 Msun

    E-Print Network [OSTI]

    M. Terasawa; K. Sumiyoshi; S. Yamada; H. Suzuki; T. Kajino

    2002-06-18

    We study the effects of the outer boundary conditions in neutrino-driven winds on the r-process nucleosynthesis. We perform numerical simulations of hydrodynamics of neutrino-driven winds and nuclear reaction network calculations of the r-process. As an outer boundary condition of hydrodynamic calculations, we set a pressure upon the outermost layer of the wind, which is approaching toward the shock wall. Varying the boundary pressure, we obtain various asymptotic thermal temperature of expanding material in the neutrino-driven winds for resulting nucleosynthesis. We find that the asymptotic temperature slightly lower than those used in the previous studies of the neutrino-driven winds can lead to a successful r-process abundance pattern, which is in a reasonable agreement with the solar system r-process abundance pattern even for the typical proto-neutron star mass Mns ~ 1.4 Msun. A slightly lower asymptotic temperature reduces the charged particle reaction rates and the resulting amount of seed elements and lead to a high neutron-to-seed ratio for successful r-process. This is a new idea which is different from the previous models of neutrino-driven winds from very massive (Mns ~ 2.0 Msun) and compact (Rns ~ 10 km) neutron star to get a short expansion time and a high entropy for a successful r-process abundance pattern. Although such a large mass is sometimes criticized from observational facts on a neutron star mass, we dissolve this criticism by reconsidering the boundary condition of the wind. We also explore the relation between the boundary condition and neutron star mass, which is related to the progenitor mass, for successful r-process.

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

    E-Print Network [OSTI]

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

    2015-06-08

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

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

    E-Print Network [OSTI]

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

    2006-12-21

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

  8. Light sterile neutrinos in the early universe

    SciTech Connect (OSTI)

    Lunardini, Cecilia [Department of Physics, Arizona State University, Tempe, Arizona 85287-1404 (United States)

    2014-06-24

    Cosmological and terrestrial data suggests the number of light neutrinos may be greater than 3, motivating a careful reexamination of cosmological bounds on extra light species. Big bang nucleosynthesis constrains the number of relativistic neutrino species present during nucleosynthesis, N{sub eff}{sup BBN}, while measurements of the cosmic microwave background (CMB) angular power spectrum constrain the effective energy density in relativistic neutrinos at the time of matter-radiation equality, N{sub eff}{sup CMB}. We review a scenario with two sterile neutrinos and explore whether partial thermalization of the sterile states can ease the tension between cosmological constraints on N{sub eff}{sup BBN} and terrestrial data. We conclude that, still, two additional light sterile neutrinos species cannot fit all the data at the 95% confidence level.

  9. Nucleosynthesis simulations for the production of the p-nuclei $^{\\text{92}}$Mo and $^{\\text{94}}$Mo in a Supernova type II model

    E-Print Network [OSTI]

    Göbel, Kathrin; Koloczek, Alexander; Pignatari, Marco; Reifarth, René; Schach, René; Sonnabend, Kerstin

    2015-01-01

    We present a nucleosynthesis sensitivity study for the $\\gamma$-process in a Supernova type II model within the NuGrid research platform. The simulations aimed at identifying the relevant local production and destruction rates for the p-nuclei of molybdenum and at determining the sensitivity of the final abundances to these rates. We show that local destruction rates strongly determine the abundance of $^{92}$Mo and $^{94}$Mo, and quantify the impact.

  10. Proton capture cross section of Sr isotopes and their importance for nucleosynthesis of proton-rich nuclides

    E-Print Network [OSTI]

    Gy. Gyurky; E. Somorjai; Zs. Fulop; S. Harissopulos; P. Demetriou; T. Rauscher

    2001-09-03

    The (p,$\\gamma$) cross sections of three stable Sr isotopes have been measured in the astrophysically relevant energy range. These reactions are important for the $p$-process in stellar nucleosynthesis and, in addition, the reaction cross sections in the mass region up to 100 are also of importance concerning the $rp$-process associated with explosive hydrogen and helium burning. It is speculated that this $rp$-process could be responsible for a certain amount of $p$-nuclei in this mass region. The (p,$\\gamma$) cross sections of $^{84,86,87}$Sr isotopes were determined using an activation technique. The measurements were carried out at the 5 MV Van de Graaff accelerator of the ATOMKI, Debrecen. The resulting cross sections are compared with the predictions of statistical model calculations. The predictions are in good agreement with the experimental results for $^{84}$Sr(p,$\\gamma$)$^{85}$Y whereas the other two reactions exhibit differences that increase with mass number. The corresponding astrophysical reaction rates have also been computed.

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

    SciTech Connect (OSTI)

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

    2013-05-01

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

  12. ALMA imaging of gas and dust in a galaxy protocluster at redshift 5.3: [C II] emission in 'typical' galaxies and dusty starbursts ?1 billion years after the big bang

    SciTech Connect (OSTI)

    Riechers, Dominik A.; Carilli, Christopher L.; Capak, Peter L.; Yan, Lin; Scoville, Nicholas Z.; Smol?i?, Vernesa; Schinnerer, Eva; Yun, Min; Cox, Pierre; Bertoldi, Frank; Karim, Alexander

    2014-12-01

    We report interferometric imaging of [C II]({sup 2} P {sub 3/2}?{sup 2} P {sub 1/2}) and OH({sup 2}?{sub 1/2} J = 3/2?1/2) emission toward the center of the galaxy protocluster associated with the z = 5.3 submillimeter galaxy (SMG) AzTEC-3, using the Atacama Large (sub)Millimeter Array (ALMA). We detect strong [C II], OH, and rest-frame 157.7 ?m continuum emission toward the SMG. The [C II]({sup 2} P {sub 3/2}?{sup 2} P {sub 1/2}) emission is distributed over a scale of 3.9 kpc, implying a dynamical mass of 9.7 × 10{sup 10} M {sub ?}, and a star formation rate (SFR) surface density of ?{sub SFR} = 530 M {sub ?} yr{sup –1} kpc{sup –2}. This suggests that AzTEC-3 forms stars at ?{sub SFR} approaching the Eddington limit for radiation pressure supported disks. We find that the OH emission is slightly blueshifted relative to the [C II] line, which may indicate a molecular outflow associated with the peak phase of the starburst. We also detect and dynamically resolve [C II]({sup 2} P {sub 3/2}?{sup 2} P {sub 1/2}) emission over a scale of 7.5 kpc toward a triplet of Lyman-break galaxies with moderate UV-based SFRs in the protocluster at ?95 kpc projected distance from the SMG. These galaxies are not detected in the continuum, suggesting far-infrared SFRs of <18-54 M {sub ?} yr{sup –1}, consistent with a UV-based estimate of 22 M {sub ?} yr{sup –1}. The spectral energy distribution of these galaxies is inconsistent with nearby spiral and starburst galaxies, but resembles those of dwarf galaxies. This is consistent with expectations for young starbursts without significant older stellar populations. This suggests that these galaxies are significantly metal-enriched, but not heavily dust-obscured, 'normal' star-forming galaxies at z > 5, showing that ALMA can detect the interstellar medium in 'typical' galaxies in the very early universe.

  13. 28/05/2009 16:25Global links will breed more dangerous parasites -University of Oxford Page 1 of 2http://www.ox.ac.uk/media/news_stories/2009/090528_3.html

    E-Print Network [OSTI]

    West, Stuart

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

  14. 15/01/2015 20:50Economic games don't show altruism | University of Oxford Page 1 of 3http://www.ox.ac.uk/news/science-blog/economic-games-dont-show-altruism

    E-Print Network [OSTI]

    West, Stuart

    .ac.uk/news/science-blog/economic-games-dont-show-altruism Charvy Narain 15 Jan 2015 Economic games don't show altruism OXFORD SCIENCE BLOG (//WWW.OX.AC.UK/NEWS/SCIENCE-BLOG) Economic 'games (http what these results are likely to mean for the field. OxSciBlog: What do these economic games involve

  15. A primer of Darwinian medicine Evolution and Medicine by Robert L. Perlman, Oxford University Press, 2013. US$49.50/27.50/s31.35 pbk (xiii + 162 pp.),

    E-Print Network [OSTI]

    Blumstein, Daniel T.

    A primer of Darwinian medicine Evolution and Medicine by Robert L. Perlman, Oxford University Press, since Williams and Nesse's landmark article that introduced us to evolutionary medicine [1], I have. Evolutionary medicine is one of those fields where discourse and advances are sorely need- ed. In addition

  16. 8/29/2014 Marine Conservation and Fisheries Management -Geography-Oxford Bibliographies -http://www.oxfordbibliographies.com/view/document/obo-9780199874002/obo-9780199874002-0073.xml?print 1/17

    E-Print Network [OSTI]

    Lopez-Carr, David

    8/29/2014 Marine Conservation and Fisheries Management - Geography- Oxford Bibliographies - http://www.oxfordbibliographies.com/view/document/obo-9780199874002/obo-9780199874002-0073.xml?print 1/17 Marine Conservation and Fisheries Management Jaime Speed Rossiter, David López-Carr Introduction Overfishing has occasioned the collapse of many coastal and marine

  17. MATHEMATICIANS MATHEMATICS INSTITUTE, OXFORD

    E-Print Network [OSTI]

    21 23 24 If you require assistance to access any of our services, events or resources, please contact · Hospitality & Tourism · International Development · IT & Telecommunications · Natural Resources & Environment

  18. Oxford System 400

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access toOctoberConsumption (MillionOtherOwen Chamberlain About the

  19. Brane world cosmology with Gauss-Bonnet and induced gravity terms

    E-Print Network [OSTI]

    Richard A. Brown

    2007-01-15

    In this thesis we investigate certain cosmological brane world models of the Randall-Sundrum type. The models are motivated by string theory but we focus on the phenomenology of the cosmology. Two models of specific interest are the Dvali-Gabadadze-Porrati (DGP, induced-gravity) model, where the brane action is modified, and the Gauss-Bonnet model where the bulk action is modified. Both of these modifications maybe motivated by string theory. We provide a brief review of Randall-Sundrum models and then consider the Kaluza-Klein modes on Minkowski and de Sitter branes, in both the two and one brane cases. The spectrum obtained for the de Sitter branes is a new result. We then consider a Friedmann-Robertson-Walker brane in order to investigate the cosmological dynamics on the brane. We present a brief discussion of the DGP and Gauss-Bonnet brane worlds. We then investigate the Gauss-Bonnet-Induced-Gravity (GBIG) model where the Gauss-Bonnet (GB) bulk term is combined with the induced-gravity (IG) brane term of the DGP model. We present a thorough investigation of cosmological dynamics, in particular focusing on GBIG models that behave like self-accelerating DGP models at late times but at early times show the remarkable feature of a finite-temperature Big Bang. We also discuss the constraints from observations, including ages and Big Bang nucleosynthesis.

  20. Carbon-enhanced metal-poor stars: a window on AGB nucleosynthesis and binary evolution. II. Statistical analysis of a sample of 67 CEMP-$s$ stars

    E-Print Network [OSTI]

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

    2015-01-01

    Many observed CEMP stars are found in binary systems and show enhanced abundances of $s$-elements. The origin of the chemical abundances of these CEMP-$s$ stars is believed to be accretion in the past of enriched material from a primary star in the AGB phase. We investigate the mechanism of mass transfer and the process of nucleosynthesis in low-metallicity AGB stars by modelling the binary systems in which the observed CEMP-$s$ stars were formed. For this purpose we compare a sample of $67$ CEMP-$s$ stars with a grid of binary stars generated by our binary evolution and nucleosynthesis model. We classify our sample CEMP-$s$ stars in three groups based on the observed abundance of europium. In CEMP$-s/r$ stars the europium-to-iron ratio is more than ten times higher than in the Sun, whereas it is lower than this threshold in CEMP$-s/nr$ stars. No measurement of europium is currently available for CEMP-$s/ur$ stars. On average our models reproduce well the abundances observed in CEMP-$s/nr$ stars, whereas in C...

  1. Nucleosynthesis in Supernovae

    E-Print Network [OSTI]

    C. J. Horowitz; Gang Li

    1999-05-19

    Core collapse supernovae are dominated by energy transport from neutrinos. Therefore, some supernova properties could depend on symetries and features of the standard model weak interactions. The cross section for neutrino capture is larger than that for antineutrino capture by one term of order the neutrino energy over the nucleon mass. This reduces the ratio of neutrons to protons in the $\

  2. Hume's System: An Examination of the First Book of His Treatise, by David Pears. New York: Oxford University Press, 1990. Reviewed by David A. Reidy, Jr., University of Kansas

    E-Print Network [OSTI]

    Reidy, David A. Jr.

    CRITICAL NOTICE Hume's System: An Examination of the First Book of His Treatise, by David Pears. New York: Oxford University Press, 1990. Reviewed by David A. Reidy, Jr., University of Kansas. In his recent book, Hume's System: An Examination... of the First Book of his Treatise, David Pears presents David Hume not as the radical skeptic many have thought him to be, but rather as a "cautious naturalist" and a "sophisticated empiricist," a philosopher willing to give his epistemological stamp...

  3. Evolution, nucleosynthesis and yields of AGB stars at different metallicities (III): intermediate mass models, revised low mass models and the ph-FRUITY interface

    E-Print Network [OSTI]

    Cristallo, S; Piersanti, L; Gobrecht, D

    2015-01-01

    We present a new set of models for intermediate mass AGB stars (4.0, 5.0 and, 6.0 Msun) at different metallicities (-2.15database. We describe the physical and chemical evolution of the computed models from the Main Sequence up to the end of the AGB phase. Due to less efficient third dredge up episodes, models with large core masses show modest surface enhancements. The latter is due to the fact that the interpulse phases are short and, then, Thermal Pulses are weak. Moreover, the high temperature at the base of the convective envelope prevents it to deeply penetrate the radiative underlying layers. Depending on the initial stellar mass, the heavy elements nucleosynthesis is dominated by different neutron sources. In particular, the s-process distributions of the more massive models are dominated by the \

  4. The D/H ratio at z=0.7 toward Q 1718+4807

    E-Print Network [OSTI]

    Sergei A. Levshakov; Wilhelm H. Kegel; Fumio Takahara

    1998-01-13

    The apparent discrepancy between low and high D abundances derived from QSO spectra may be caused by spatial correlations in the stochastic velocity field. If one accounts for such correlations, one finds good agreement between different observations and the theoretical predictions for standard big bang nucleosynthesis (SBBN). In particular, we show that the H+D Ly-alpha profile observed at z = 0.7 toward Q1718+4807 is compatible with 4.1*10^{-5} <= D/H <= 4.7*10^{-5}. This result is consistent with our previous D/H determination for the z = 2.504 system toward Q1009+2956 and, thus, supports SBBN.

  5. The primordial deuterium abundance : problems and prospects

    E-Print Network [OSTI]

    Sergei A. Levshakov; Fumio Takahara; Wilhelm H. Kegel

    1997-12-10

    The current status of extragalactic deuterium abundance is discussed using two examples of `low' and `high' D/H measurements. We show that the discordance of these two types of D abundances may be a consequence of the spatial correlations in the stochastic velocity field. Within the framework of the generalized procedure (accounting for such effects) one finds good agreement between different observations and the theoretical predictions for standard big bang nucleosynthesis (SBBN). In particular, we show that the deuterium absorption seen at z = 2.504 toward Q1009+2956 and the H+D Ly-alpha profile observed at z = 0.701 toward Q1718+4807 are compatible with D/H $\\sim 4.1 - 4.6\\times10^{-5}$. This result supports SBBN and, thus, no inhomogeneity is needed. The problem of precise D/H measurements is discussed.

  6. WMAPping out Neutrino Masses

    E-Print Network [OSTI]

    Aaron Pierce; Hitoshi Murayama

    2003-10-28

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

  7. Is there further evidence for spatial variation of fundamental constants?

    SciTech Connect (OSTI)

    Berengut, J. C.; Flambaum, V. V.; King, J. A.; Curran, S. J.; Webb, J. K.

    2011-06-15

    Indications of spatial variation of the fine-structure constant, {alpha}, based on study of quasar absorption systems have recently been reported [J. K. Webb, J. A. King, M. T. Murphy, V. V. Flambaum, R. F. Carswell, and M. B. Bainbridge, arXiv:1008.3907.]. The physics that causes this {alpha}-variation should have other observable manifestations, and this motivates us to look for complementary astrophysical effects. In this paper we propose a method to test whether spatial variation of fundamental constants existed during the epoch of big bang nucleosynthesis and study existing measurements of deuterium abundance for a signal. We also examine existing quasar absorption spectra data that are sensitive to variation of the electron-to-proton mass ratio {mu} and x={alpha}{sup 2{mu}}g{sub p} for spatial variation.

  8. A m\\'enage \\`a trois of eV-scale sterile neutrinos, cosmology, and structure formation

    E-Print Network [OSTI]

    Dasgupta, Basudeb

    2014-01-01

    We show that sterile neutrinos with masses larger than 1 eV, as motivated by several short-baseline oscillation anomalies, can be consistent with cosmological constraints if they are charged under a hidden sector force mediated by a light boson. In this case, sterile neutrinos experience a large thermal potential that suppresses mixing between active and sterile neutrinos in the early Universe, even if vacuum mixing angles are large. Thus, the abundance of sterile neutrinos in the Universe remains very small, and their impact on Big Bang Nucleosynthesis, on the Cosmic Microwave Background, and on large-scale structure formation is negligible. It is conceivable that the new gauge force also couples to dark matter, possibly ameliorating some of the small-scale structure problems associated with cold dark matter.

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

    E-Print Network [OSTI]

    Kazunori Kohri; Anupam Mazumdar; Narendra Sahu

    2009-05-11

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

  10. Total cross section of the 3H(p,n)3He reaction from threshold to 4.5 MeV

    E-Print Network [OSTI]

    C. R. Brune; K. I. Hahn; R. W. Kavanagh; P. R. Wrean

    1999-02-22

    We report new measurements of the total cross section for the 3H(p,n)3He reaction from threshold (Ep=1.02 MeV) to Ep=4.5 MeV. The experiment utilized specially prepared Ti-3H targets, and neutrons were detected using a 4-pi detector. A weak resonant structure due to an excited state in 4He is observed which was not seen in previous cross section measurements. A new expression for the 3He(n,p)3H thermonuclear reaction rate for temperatures below 10 GK is presented which will allow for more accurate calculations of the yields of light elements produced by big-bang nucleosynthesis.

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

    E-Print Network [OSTI]

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

    2008-01-30

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

  12. Measurement of the neutron capture cross section of {sup 15}N J

    SciTech Connect (OSTI)

    MeiBner, N.J.; Schatz, H.; Herndl, H.; Wiescher, M.

    1995-10-01

    Neutron capture reactions on fight nuclei may be of considerable importance for the s-process nucleosynthesis in red giant stars as well as in inhomogeneous big bang scenarios and high entropy supernovae neutrino bubbles. To determine the reaction rates for such different temperature conditions, the cross sections need to be known for a wide energy range. The reaction {sup 15}N(n,{gamma}) represents an important link in the reaction seququences for the production of heavier isotopes in such scenarios. At high temperature conditions, the cross section is not only influenced by a non resonant a-wave contribution but also by a non resonant p-wave contribution and higher energy resonances. The (n,{gamma}) cross section has been measured at the Forschungszentrum Karlsruhe for different neutron energies using a fast cyclic neutron activation technique. The technique and the results will be presented.

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

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

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

  14. Neutrinos, WMAP, and BBN

    E-Print Network [OSTI]

    Lawrence M. Krauss; Cecilia Lunardini; Christel Smith

    2010-11-18

    New data from WMAP have appeared, related to both the fractional energy density in relativistic species at decoupling and also the primordial helium abundance, at the same time as other independent observational estimates suggest a higher value of the latter than previously estimated. All the data are consistent with the possibility that the effective number of relativistic species in the radiation gas at the time of Big Bang Nucleosynthesis may exceed the value of 3, as expected from a CP-symmetric population of the known neutrino species. Here we explore the possibility that new neutrino physics accounts for such an excess. We explore different realizations, including neutrino asymmetry and new neutrino species, as well as their combination, and describe how existing constraints on neutrino physics would need to be relaxed as a result of the new data, as well as possible experimental tests of these possibilities.

  15. Manifestations of dark matter and variations of fundamental constants in atoms and astrophysical phenomena

    E-Print Network [OSTI]

    Stadnik, Y V

    2015-01-01

    We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects (solitons). We emphasise new high-precision laboratory and astrophysical measurements, in which the sought effects are linear in the underlying interaction strength between dark matter and ordinary matter, in contrast to traditional detection schemes for dark matter, where the effects are quadratic or higher order in the underlying interaction parameters and are extremely small. New terrestrial experiments include measurements with atomic clocks, spectroscopy, atomic and solid-state magnetometry, torsion pendula, ultracold neutrons, and laser interferometry. New astrophysical observations include pulsar timing, cosmic radiation lensing, Big Bang nucleosynthesis and cosmic microwave background measurements. We also discuss various recently proposed mechanisms for the inducti...

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

    E-Print Network [OSTI]

    Vivian Poulin; Pasquale D. Serpico

    2015-03-04

    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.

  17. Conversion of relic gravitational waves into photons in cosmological magnetic fields

    SciTech Connect (OSTI)

    Dolgov, Alexander D.; Ejlli, Damian, E-mail: dolgov@fe.infn.it, E-mail: ejlli@fe.infn.it [Dipartimento di Fisica e Scienze della Terra, Polo Scientifico e Tecnologico-Edificio C, Università degli Studi di Ferrara, Via Saragat 1, 44122 Ferrara (Italy)

    2012-12-01

    Conversion of gravitational waves into electromagnetic radiation is discussed. The probability of transformations of gravitons into photons in presence of cosmological background magnetic field is calculated at the recombination epoch and during subsequent cosmological stages. The produced electromagnetic radiation is concentrated in the X-ray part of the spectrum. It is shown that if the early Universe was dominated by primordial black holes (PBHs) prior to Big Bang Nucleosynthesis (BBN), the relic gravitons emitted by PBHs would transform to an almost isotropic background of electromagnetic radiation due to conversion of gravitons into photons in cosmological magnetic fields. Such extragalactic radiation could be noticeable or even dominant component of Cosmic X-ray Background.

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

    SciTech Connect (OSTI)

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

    2013-10-01

    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.

  19. CONSTRAINING PRIMORDIAL MAGNETIC FIELDS THROUGH LARGE-SCALE STRUCTURE

    SciTech Connect (OSTI)

    Kahniashvili, Tina; Natarajan, Aravind; Battaglia, Nicholas [McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States); Maravin, Yurii [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States); Tevzadze, Alexander G., E-mail: tinatin@andrew.cmu.edu [Faculty of Exact and Natural Sciences, Javakhishvili Tbilisi State University, 3 Chavchavadze Avenue, Tbilisi 0128 (Georgia)

    2013-06-10

    We study primordial magnetic field effects on the matter perturbations in the universe. We assume magnetic field generation prior to the big bang nucleosynthesis (BBN), i.e., during the radiation-dominated epoch of the universe expansion, but do not limit analysis by considering a particular magnetogenesis scenario. Contrary to previous studies, we limit the total magnetic field energy density and not the smoothed amplitude of the magnetic field at large (of the order of 1 Mpc) scales. We review several cosmological signatures, such as halo abundance, thermal Sunyaev-Zel'dovich effect, and Ly{alpha} data. For a cross-check, we compare our limits with that obtained through the cosmic microwave background faraday rotation effect and BBN. The limits range between 1.5 nG and 4.5 nG for n{sub B} in (- 3; -1.5).

  20. More on cosmological constraints on spontaneous R-symmetry breaking models

    SciTech Connect (OSTI)

    Hamada, Yuta; Kobayashi, Tatsuo [Department of Physics, Kyoto University, Kyoto, 606-8502 (Japan); Kamada, Kohei [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, Hamburg, D-22607 (Germany); Ookouchi, Yutaka, E-mail: hamada@gauge.scphys.kyoto-u.ac.jp, E-mail: kohei.kamada@epfl.ch, E-mail: kobayash@gauge.scphys.kyoto-u.ac.jp, E-mail: yutaka.ookouchi@artsci.kyushu-u.ac.jp [Faculty of Arts and Science, Kyushu University, Fukuoka, 819–0395 (Japan)

    2014-01-01

    We study the spontaneous R-symmetry breaking model and investigate the cosmological constraints on this model due to the pseudo Nambu-Goldstone boson, R-axion. We consider the R-axion which has relatively heavy mass in order to complement our previous work. In this regime, model parameters, R-axions mass and R-symmetry breaking scale, are constrained by Big Bang Nucleosynthesis and overproduction of the gravitino produced from R-axion decay and thermal plasma. We find that the allowed parameter space is very small for high reheating temperature. For low reheating temperature, the U(1){sub R} breaking scale f{sub a} is constrained as f{sub a} < 10{sup 12?14} GeV regardless of the value of R-axion mass.

  1. Dark radiation constraints on minicharged particles in models with a hidden photon

    SciTech Connect (OSTI)

    Vogel, Hendrik; Redondo, Javier, E-mail: hvogel@mpp.mpg.de, E-mail: redondo@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, D-80805 München (Germany)

    2014-02-01

    We compute the thermalization of a hidden sector consisting of minicharged fermions (MCPs) and massless hidden photons in the early Universe. The precise measurement of the anisotropies of the cosmic microwave background (CMB) by Planck and the relic abundance of light nuclei produced during big bang nucleosynthesis (BBN) constrain the amount of dark radiation of this hidden sector through the effective number of neutrino species, N{sub eff}. This study presents novel and accurate predictions of dark radiation in the strongly and weakly coupled regime for a wide range of model parameters. We give the value of N{sub eff} for MCP masses between ? 100 keV and 10 GeV and minicharges in the range 10{sup ?11}?1. Our results can be used to constrain MCPs with the current data and they are also a valuable indicator for future experimental searches, should the hint for dark radiation manifest itself in the next release of Planck's data.

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

    E-Print Network [OSTI]

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

    2009-10-01

    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.

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

    E-Print Network [OSTI]

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

    2008-09-30

    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.

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

    E-Print Network [OSTI]

    Sachiko Kuroyanagi; Tomo Takahashi; Shuichiro Yokoyama

    2014-07-17

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

  5. How to Avoid a Swift Kick in the Chameleons

    E-Print Network [OSTI]

    Padilla, Antonio; Stefanyszyn, David; Walters, Anthony; Weltman, Amanda; Wilson, Toby

    2015-01-01

    Recently, it was argued that the conformal coupling of the chameleon to matter fields created an issue for early universe cosmology. As standard model degrees of freedom become non-relativistic in the early universe, the chameleon is attracted towards a "surfing" solution, so that it arrives at the potential minimum with too large a velocity. This leads to rapid variations in the chameleon's mass and excitation of high energy modes, casting doubts on the classical treatment at Big Bang Nucleosynthesis. Here we present the DBI chameleon, a consistent high energy modification of the chameleon theory that dynamically renders it weakly coupled to matter during the early universe thereby eliminating the adverse effects of the `kicks'. This is done without any fine tuning of the coupling between the chameleon and matter fields, and retains its screening ability in the solar system. We demonstrate this explicitly with a combination of analytic and numerical results.

  6. How to Avoid a Swift Kick in the Chameleons

    E-Print Network [OSTI]

    Antonio Padilla; Emma Platts; David Stefanyszyn; Anthony Walters; Amanda Weltman; Toby Wilson

    2015-11-18

    Recently, it was argued that the conformal coupling of the chameleon to matter fields created an issue for early universe cosmology. As standard model degrees of freedom become non-relativistic in the early universe, the chameleon is attracted towards a "surfing" solution, so that it arrives at the potential minimum with too large a velocity. This leads to rapid variations in the chameleon's mass and excitation of high energy modes, casting doubts on the classical treatment at Big Bang Nucleosynthesis. Here we present the DBI chameleon, a consistent high energy modification of the chameleon theory that dynamically renders it weakly coupled to matter during the early universe thereby eliminating the adverse effects of the `kicks'. This is done without any fine tuning of the coupling between the chameleon and matter fields, and retains its screening ability in the solar system. We demonstrate this explicitly with a combination of analytic and numerical results.

  7. PRODUCTION OF {sup 9}Be THROUGH THE {alpha}-FUSION REACTION OF METAL-POOR COSMIC RAYS AND STELLAR FLARES

    SciTech Connect (OSTI)

    Kusakabe, Motohiko; Kawasaki, Masahiro E-mail: kawasaki@icrr.u-tokyo.ac.jp

    2013-04-10

    Spectroscopic observations of metal-poor stars have indicated possible {sup 6}Li abundances that are much larger than the primordial abundance predicted in the standard big bang nucleosynthesis model. Possible mechanisms of {sup 6}Li production in metal-poor stars include pregalactic and cosmological cosmic-ray (CR) nucleosynthesis and nucleosynthesis by flare-accelerated nuclides. We study {sup 9}Be production via two-step {alpha}-fusion reactions of CR or flare-accelerated {sup 3,4}He through {sup 6}He and {sup 6,7}Li, in pregalactic structure, intergalactic medium, and stellar surfaces. We solve transfer equations of CR or flare particles and calculate nuclear yields of {sup 6}He, {sup 6,7}Li, and {sup 9}Be taking account of probabilities of processing {sup 6}He and {sup 6,7}Li into {sup 9}Be via fusions with {alpha} particles. Yield ratios, i.e., {sup 9}Be/{sup 6}Li, are then calculated for the CR and flare nucleosynthesis models. We suggest that the future observations of {sup 9}Be in metal-poor stars may find enhanced abundances originating from metal-poor CR or flare activities.

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

    E-Print Network [OSTI]

    Allen, P D; Dalton, G; MacDonald, E; Blake, C; Clewley, L; Heymans, C; Wegner, G; Allen, Paul D.; Moustakas, Leonidas A.; Dalton, Gavin; Donald, Emily Mac; Blake, Chris; Clewley, Lee; Heymans, Catherine; Wegner, Gary

    2005-01-01

    We present measurements of the clustering properties of bright ($L>L_{*}$) z$\\sim$4 Lyman Break Galaxies (LBGs) selected from the Oxford-Dartmouth Thirty Degree Survey (ODT). We describe techniques used to select and evaluate our candidates and calculate the angular correlation function which we find best fitted by a power law, $\\omega(\\theta)=A_{w}\\theta^{-\\beta}$ with $A_{w}=15.4$ (with $\\theta$ in arcseconds), using a constrained slope of $\\beta=0.8$. Using a redshift distribution consistent with photometric models, we deproject this correlation function and find a comoving $r_{0}=11.4_{-1.9}^{+1.7}$ h$_{100}^{-1}$ Mpc in a $\\Omega_m=0.3$ flat $\\Lambda$ cosmology for $i_{AB}\\leq24.5$. This corresponds to a linear bias value of $b=8.1_{-2.6}^{+2.0}$ (assuming $\\sigma_{8}=0.9$). These data show a significantly larger $r_{0}$ and $b$ than previous studies at $z\\sim4$. We interpret this as evidence that the brightest LBGs have a larger bias than fainter ones, indicating a strong luminosity dependence for the m...

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

    E-Print Network [OSTI]

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

    2015-05-09

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

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

    SciTech Connect (OSTI)

    Fujimoto, Shin-ichiro; Kotake, Kei; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2011-09-01

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

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

    SciTech Connect (OSTI)

    Placco, Vinicius M.; Rossi, Silvia [Departamento de Astronomia-Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Sao Paulo, SP 05508-900 (Brazil); Frebel, Anna [Massachusetts Institute of Technology and Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Karakas, Amanda I.; Kennedy, Catherine R. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Christlieb, Norbert [Zentrum fuer Astronomie der Universitaet Heidelberg, Landessternwarte, Koenigstuhl 12, D-69117 Heidelberg (Germany); Stancliffe, Richard J. [Argelander-Institut fuer Astronomie der Universitaet Bonn, Auf dem Huegel 71, D-53121 Bonn (Germany)

    2013-06-20

    We present a comprehensive abundance analysis of two newly discovered carbon-enhanced metal-poor (CEMP) stars. HE 2138-3336 is a s-process-rich star with [Fe/H] = -2.79, and has the highest [Pb/Fe] abundance ratio measured thus far, if non-local thermodynamic equilibrium corrections are included ([Pb/Fe] = +3.84). HE 2258-6358, with [Fe/H] = -2.67, exhibits enrichments in both s- and r-process elements. These stars were selected from a sample of candidate metal-poor stars from the Hamburg/ESO objective-prism survey, and followed up with medium-resolution (R {approx} 2000) spectroscopy with GEMINI/GMOS. We report here on derived abundances (or limits) for a total of 34 elements in each star, based on high-resolution (R {approx} 30, 000) spectroscopy obtained with Magellan-Clay/MIKE. Our results are compared to predictions from new theoretical asymptotic giant branch (AGB) nucleosynthesis models of 1.3 M{sub Sun} with [Fe/H] = -2.5 and -2.8, as well as to a set of AGB models of 1.0 to 6.0 M{sub Sun} at [Fe/H] = -2.3. The agreement with the model predictions suggests that the neutron-capture material in HE 2138-3336 originated from mass transfer from a binary companion star that previously went through the AGB phase, whereas for HE 2258-6358, an additional process has to be taken into account to explain its abundance pattern. We find that a narrow range of progenitor masses (1.0 {<=} M(M{sub Sun }) {<=} 1.3) and metallicities (-2.8 {<=} [Fe/H] {<=}-2.5) yield the best agreement with our observed elemental abundance patterns.

  12. Oxford Innovation | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History ViewMayo, Maryland:NPIProtectio Program | OpenWisconsin:NewOver Core

  13. Oxford, Ohio, Site Fact Sheet

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouthReport for the Weldon Spring,7=cr5rnP 7694 i+lJNewS eFOURTHOxford,

  14. Adrian Cooper CEO, Oxford Economics

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (Billion Cubic Feet) Wyoming Dry NaturalPrices1 Table 1.10 CoolingNotes &*GinaSpring

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

    E-Print Network [OSTI]

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

    1998-06-05

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

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

    E-Print Network [OSTI]

    T. Kiang

    2003-05-27

    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.

  17. A new paradigm for the universe

    E-Print Network [OSTI]

    Colin Rourke

    2012-01-25

    A new paradigm for the universe is presented in which the universe is far older than current estimates and there is no big bang.

  18. Light-element nucleosynthesis in a molecular cloud interacting with a supernova remnant and the origin of beryllium-10 in the protosolar nebula

    SciTech Connect (OSTI)

    Tatischeff, Vincent; Duprat, Jean [Centre de Sciences Nucléaires et de Sciences de la Matière, IN2P3-CNRS and Univ Paris-Sud, F-91405 Orsay Cedex (France); De Séréville, Nicolas, E-mail: Vincent.Tatischeff@csnsm.in2p3.fr [Institut de Physique Nucléaire d'Orsay, IN2P3-CNRS and Univ Paris-Sud, F-91405 Orsay Cedex (France)

    2014-12-01

    The presence of short-lived radionuclides (t {sub 1/2} < 10 Myr) in the early solar system provides important information about the astrophysical environment in which the solar system formed. The discovery of now extinct {sup 10}Be (t {sub 1/2} = 1.4 Myr) in calcium-aluminum-rich inclusions (CAIs) with Fractionation and Unidentified Nuclear isotope anomalies (FUN-CAIs) suggests that a baseline concentration of {sup 10}Be in the early solar system was inherited from the protosolar molecular cloud. In this paper, we investigate various astrophysical contexts for the nonthermal nucleosynthesis of {sup 10}Be by cosmic-ray-induced reactions. We first show that the {sup 10}Be recorded in FUN-CAIs cannot have been produced in situ by irradiation of the FUN-CAIs themselves. We then show that trapping of Galactic cosmic rays (GCRs) in the collapsing presolar cloud core induced a negligible {sup 10}Be contamination of the protosolar nebula, the inferred {sup 10}Be/{sup 9}Be ratio being at least 40 times lower than that recorded in FUN-CAIs ({sup 10}Be/{sup 9}Be ? 3 × 10{sup –4}). Irradiation of the presolar molecular cloud by background GCRs produced a steady-state {sup 10}Be/{sup 9}Be ratio ? 1.3 × 10{sup –4} at the time of the solar system formation, which suggests that the presolar cloud was irradiated by an additional source of CRs. Considering a detailed model for CR acceleration in a supernova remnant (SNR), we find that the {sup 10}Be abundance recorded in FUN-CAIs can be explained within two alternative scenarios: (1) the irradiation of a giant molecular cloud by CRs produced by ? 50 supernovae exploding in a superbubble of hot gas generated by a large star cluster of at least 20,000 members, and (2) the irradiation of the presolar molecular cloud by freshly accelerated CRs escaped from an isolated SNR at the end of the Sedov-Taylor phase. In the second picture, the SNR resulted from the explosion of a massive star that ran away from its parent OB association, expanded during most of its adiabatic phase in an intercloud medium of density of about 1 H-atom cm{sup –3}, and eventually interacted with the presolar molecular cloud only during the radiative stage. This model naturally provides an explanation for the injection of other short-lived radionuclides of stellar origin into the cold presolar molecular cloud ({sup 26}Al, {sup 41}Ca, and {sup 36}Cl) and is in agreement with the solar system originating from the collapse of a molecular cloud shocked by a supernova blast wave.

  19. Analysis of laboratory nucleosynthesis products

    E-Print Network [OSTI]

    S. V. Adamenko; A. S. Adamenko

    2003-07-11

    We present the results of the experimental study on synthesis of a wide range of isotopes in a superdense plasma. The initial conditions necessary for plasma bunch formation were provided by specially organized coherent impact on a solid target with a total energy up to 1 kJ. More than 4000 shots were performed with various targets made of light, medium, and heavy elements. Subsequent analysis of the products of the target explosion reveals the presence of a wide range of elements absent in the initial materials. Elements with nuclei three and more times heavier than the nucleus of the target main element are detected in the products. The isotopic composition of the produced elements significantly differs from the natural one. The presence of unknown superheavy elements at the border of the periodic table and beyond it was detected by several different spectroscopic methods of elemental and isotopic analyzes.

  20. Primordial nucleosynthesis and neutrino physics

    E-Print Network [OSTI]

    Smith, Christel Johanna

    2009-01-01

    A Brief History of and Introduction to Neutrino Physics . 13Theoretical Nuclear Physics, Volume I: Nuclear Structure, 1McGregor, in Particle Physics and Cosmology: Third Tropical