相关论文: Measurements of Nuclear Reactions that Create and …
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…
This article presents an original code for Big Bang Nucleosynthesis in a baryon inhomogeneous model of the universe. In this code neutron diffusion between high and low baryon density regions is calculated simultaneously with the nuclear…
We reconsider the effects of unstable particles on the production and destruction of the primordial light elements, with a view to reconciling the high primordial Li7 abundance deduced from Big Bang Nucleosynthesis (BBN), as implied by the…
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…
In the first thousand seconds of its evolution the Universe was a primordial nuclear reactor synthesizing the nuclides D, $^3$He, $^4$He and $^7$Li. These messengers from the Big Bang provide a unique window on the early, hot, dense…
We present a detailed study of inhomogeneous Big Bang nucleosynthesis where, for the first time, nuclear reactions are coupled to all significant fluctuation dissipation processes. Theses processes include neutrino heat transport, baryon…
We consider the effect on Big Bang Nucleosynthesis (BBN) of new measurements of the $d(p,\gamma){}^3$He cross section by the LUNA Collaboration. These have an important effect on the primordial abundance of D/H which is also sensitive to…
In both the Sun and the early universe, the 3He(alpha,gamma)7Be reaction plays a key role. The rate of this reaction is the least certain nuclear input needed to calculate both the primordial 7Li abundance in big bang nucleosynthesis (BBN)…
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…
Primordial nucleosynthesis is inevitable during the early evolution of an expanding universe filled with radiation and matter (baryons). However, the precise abundance yields depend sensitively on the baryon density, the radiation content…
We investigate the effect of a variation of fundamental constants on primordial element production in Big Bang nucleosynthesis (BBN). We focus on the effect of a possible change in the nucleon-nucleon interaction on nuclear reaction rates…
We show that the predicted primordial helium production is significantly reduced when new measurements of the neutron lifetime and the implied enhancement in the weak reaction rates are included in big-bang nucleosynthesis. Therefore, even…
Using the cosmological constants derived from WMAP, the standard big bang nucleosynthesis (SBBN) predicts the light elements primordial abundances for 4He, 3He, D, 6Li and 7Li. These predictions are in satisfactory agreement with the…
During Big Bang Nucleosynthesis (BBN), in the first 20 minutes of the evolution of the Universe, the light nuclides, D, 3He, 4He, and 7Li were synthesized in astrophysically interesting abundances. The Cosmic Microwave Background Radiation…
Two dimensional concordance plots involving the baryon-to-photon ratio, $\eta$, and an effective number of light neutrinos, $N_{\nu}$, are used to discuss the overall consistency of standard big-bang nucleosynthesis in light of recent…
We report the results on Big Bang Nucleosynthesis (BBN) based on an updated code, with accuracy of the order of 0.1% on He4 abundance, compared with the predictions of other recent similar analysis. We discuss the compatibility of the…
The Big Bang nucleosynthesis (BBN) in the presence of charged massive particles (CHAMPs) is studied in detail. All currently known effects due to the existence of bound states between CHAMPs and nuclei, including possible late-time…
We investigate the effect of a variation of fundamental constants on primordial element production in big bang nucleosynthesis (BBN). We focus on the effect of a possible change in the nucleon-nucleon interaction on nuclear reaction rates…
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…
We point out that the cosmological abundance of ${}^7$Li can be reduced down to observed values if during its formation Big Bang Nucleosynthesis is modified by the presence of light electrically neutral particles $X$ that have substantial…