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相关论文: Quantifying the sensitivity of Big Bang Nucleosynt…

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Precision on primordial abundances, deduced from observations, have now reached the percent level for 4He and deuterium. Precision on big bang nucleosynthesis (BBN) predictions should, hence, reach the same level. The uncertainty on the 4He…

宇宙学与河外天体物理 · 物理学 2019-09-27 Cyril Pitrou , Alain Coc , Jean-Philippe Uzan , Elisabeth Vangioni

This paper is superseded by Arxiv:1911.07334. Big-bang nucleosynthesis (BBN) is a valuable tool to constrain the physics of the early universe and is the only probe of the radiation-dominated epoch. A fundamental assumption in BBN is that…

宇宙学与河外天体物理 · 物理学 2020-07-01 Nishanth Sasankan , Atul Kedia , Motohiko Kusakabe , Grant J Mathews

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…

天体物理学 · 物理学 2010-04-30 Christel J. Smith , George M. Fuller , Michael S. Smith

We present results of a perturbative QCD analysis of deep inelastic measurements of both the deuteron and proton structure functions. We evaluate the theoretical uncertainty associated to nuclear effects in the deuteron, and we extract…

高能物理 - 唯象学 · 物理学 2014-11-17 S. I. Alekhin , S. A. Kulagin , S. Liuti

The fragment production in collisions of $^{48,50}$Ca+$^{12}$C at 50 MeV/nucleon are simulated via the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model followed by the {GEMINI code}. {By changing the diffuseness parameter of…

核理论 · 物理学 2015-04-02 Z. T. Dai , D. Q. Fang , Y. G. Ma , X. G. Cao , G. Q. Zhang , W. Q. Shen

Within an isospin and momentum dependent transport model, the dynamics of isospin particles (nucleons and light clusters) in Fermi-energy heavy-ion collisions are investigated for constraining the isospin splitting of nucleon effective mass…

核理论 · 物理学 2017-09-15 Ya-Fei Guo , Peng-Hui Chen , Fei Niu , Hong-Fei Zhang , Gen-Ming Jin , Zhao-Qing Feng

One of the three testaments in favor of the big bang theory is the prediction of the primordial elemental abundances in the big-bang nucleosynthesis (BBN). The Standard BBN is a parameter-free theory due to the precise knowledge of the…

核理论 · 物理学 2024-05-28 Vinay Singh , Debasis Bhowmick , D. N. Basu

Big Bang Nucleosynthesis (BBN) is very sensitive to the cosmological expansion rate. If the gravitational constant $G$ took a different value during the nucleosynthesis epoch than today, the primordial abundances of light elements would be…

宇宙学与河外天体物理 · 物理学 2020-03-18 James Alvey , Nashwan Sabti , Miguel Escudero , Malcolm Fairbairn

We reinvestigate the constraints from primordial nucleosynthesis on a possible time-dependent quark mass. The limits on such quark-mass variations are particularly sensitive to the adopted observational abundance constraints. Hence, in the…

宇宙学与河外天体物理 · 物理学 2014-05-06 Myung-Ki Cheoun , Toshitaka Kajino , Motohiko Kusakabe , Grant J. Mathews

We present a method to evaluate on the lattice the leading isospin breaking effects due to both the small mass difference between the up and down quarks and the QED interaction. Our proposal is applicable in principle to any QCD+QED gauge…

高能物理 - 格点 · 物理学 2013-06-12 G. M. de Divitiis , R. Frezzotti , V. Lubicz , G. Martinelli , R. Petronzio , G. C. Rossi , F. Sanfilippo , S. Simula , N. Tantalo

The existence and stability of atoms rely on the fact that neutrons are more massive than protons. The measured mass difference is only 0.14\% of the average of the two masses. A slightly smaller or larger value would have led to a…

高能物理 - 格点 · 物理学 2015-04-08 Sz. Borsanyi , S. Durr , Z. Fodor , C. Hoelbling , S. D. Katz , S. Krieg , L. Lellouch , T. Lippert , A. Portelli , K. K. Szabo , B. C. Toth

We study Big Bang Nucleosynthesis (BBN) constraints on heavy QCD axions. BBN offers a powerful probe of new physics that modifies the neutron-to-proton ratio during the process, thanks to the precisely measured primordial Helium-4…

高能物理 - 唯象学 · 物理学 2026-03-11 Tae Hyun Jung , Takemichi Okui , Kohsaku Tobioka , Jiabao Wang

The neutron-proton effective mass splitting in neutron-rich nucleonic matter reflects the space-time nonlocality of the isovector nuclear interaction. It affects the neutron/proton ratio during the earlier evolution of the Universe, cooling…

核理论 · 物理学 2015-04-14 Bao-An Li , Lie-Wen Chen

We consider the effects of uncertainties in nuclear reaction rates on the cosmological constraints on the decays of unstable particles during or after Big-Bang nucleosynthesis (BBN). We identify the nuclear reactions due to non-thermal…

宇宙学与河外天体物理 · 物理学 2011-04-08 Richard H. Cyburt , John Ellis , Brian D. Fields , Feng Luo , Keith A. Olive , Vassilis C. Spanos

Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be classified as elemental abundance, isotopic abundance, and abundance of nuclei. In this work we propose to change nucleon identification from the…

核实验 · 物理学 2015-02-25 Miklos Kiss

To elucidate the significance of the effect of systematic uncertainties in light element abundance estimates on cosmological bounds derivable from Big Bang Nucleosynthesis (BBN) we present tables giving bounds on $\Omega_{baryon}$ and…

天体物理学 · 物理学 2009-10-22 Lawrence M. Krauss , Peter J. Kernan

We study the dependence of the primordial nuclear abundances as a function of the electromagnetic fine-structure constant $\alpha$, keeping all other fundamental constants fixed. We update the leading nuclear reaction rates, in particular…

高能物理 - 理论 · 物理学 2023-05-26 Ulf-G. Meißner , Bernard Ch. Metsch , Helen Meyer

Big Bang Nucleosynthesis (BBN) explores the first few minutes of nuclei formation after the Big Bang. We present updates that result in new constraints at the 2{\sigma} level for the abundances of the four primary light nuclides -…

宇宙学与河外天体物理 · 物理学 2017-09-20 Michael Foley , Nishanth Sasankan , Motohiko Kusakabe , Grant. J. Mathews

We study big bang nucleosynthesis in the presence of large mass-scale, non-linear entropy fluctuations. Overdense regions, with masses above the local baryon-Jeans mass, are expected to collapse and form condensed objects. Surviving…

天体物理学 · 物理学 2009-10-22 K. Jedamzik , G. M. Fuller

The decreasing uncertainties in theoretical predictions and experimental measurements of several hadronic observables related to weak processes, which in many cases are now smaller than $\mathrm{O}(1\%)$, require theoretical calculations to…