Big bang nucleosynthesis with a varying fine structure constant and nonstandard expansion rate

Big bang nucleosynthesis with a varying fine structure constant and non - standard expansion rate

We calculate primordial abundances of light elements produced during big bang nucleosynthesis when the fine structure constant and/or the cosmic expansion rate take non-standard values. We compare them with the recent values of observed D, He and Li abundances, which show slight inconsistency among themselves in the standard big bang nucleosynthesis scenario. This inconsistency is not solved by...

Structure Constant from Big Bang Nucleosynthesis

We put bounds on the variation of the value of the fine structure constant α, at the time of Big Bang nucleosynthesis. We study carefully all light elements up to 7Li. We correct a previous upper limit on |∆α/α| estimated from 4He primordial abundance and we find interesting new potential limits (depending on the value of the baryon-to-photon ratio) from 7Li, whose production is governed to a l...

Big Bang Nucleosynthesis

Big Bang Nucleosynthesis: Reprise

Recent observational and theoretical developments concerning the primordial synthesis of the light elements are reviewed, and the implications for dark matter mentioned.

Assessing Big-Bang nucleosynthesis.

Systematic uncertainties in the light-element abundances and their evolution make a rigorous statistical assessment difficult. However, using Bayesian methods we show that the following statement is robust: the predicted and measured abundances are consistent with 95% credibility only if the baryon-to-photon ratio is between 2× 10 and 6.5× 10 and the number of light neutrino species is less tha...