Big bang nucleosynthesis: Present status

Big Bang Nucleosynthesis: Current Status

During its hot, dense, early evolution the Universe was a primordial nuclear reactor, synthesizing the light nuclides D, He, He and Li in the first thousand seconds. The presently observed abundances of these relic nuclides provide a unique window on the early Universe. The implications of current observations for cosmology (the universal density of nucleons) and for particle physics (new parti...

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...

Big Bang Nucleosynthesis Calculation

I review standard big bang nucleosynthesis and some versions of nonstandard BBN. The abundances of the primordial isotopes D, He-3, and Li-7 produced in standard BBN can be calculated as a function of the baryon density with an accuracy of about 10%. For He-4 the accuracy is better than 1%. The calculated abundances agree fairly well with observations, but the baryon density of the universe can...