Chemical Origins: Nuclear Chemistry in the Early Universe

摘要

Big bang nucleosynthesis (BBN), describes the production of the light elements in the early universe. The theoretical prediction for the abundances of D, ~3He, ~4He, and ~7Li is discussed and compared with their observational determination. The spectrum of anisotropies in the cosmic microwave background (CMB) now independently measures the baryon density to high precision. As a result, the CMB data test BBN. One finds that the CMB along with D and ~4He observations paint a consistent picture. This concordance stands as a major success of the hot big bang. On the other hand, ~7Li remains discrepant with the CMB-preferred baryon density; possible explanations are reviewed.