Big Bang Nucleosynthesis in the Post-WMAP Era

An overview of the standard model of big bang nucleosynthesis (BBN) in the post-WMAP era is presented. With the value of the baryon-to-photon ratio determined to relatively high precision by WMAP, standard BBN no longer has any free parameters. In this context, the theoretical prediction for the abundances of D, ³He, ⁴He, and ⁷Li is discussed. The observational determination of the light nuclides is also discussed. While, the D and ⁴He observations are concordant with BBN predictions, ⁷Li remains discrepant with the CMB-preferred baryon density and possible explanations are reviewed. Finally, moving beyond the standard model, primordial nucleosynthesis constraints on early universe and particle physics are also briefly discussed.