Primordial Nucleosynthesis in the Precision Cosmology Era

Primordial nucleosynthesis probes the Universe during its early evolution. Given the progress in exploring the constituents, structure, and recent evolution of the Universe, it is timely to review the status of Big Bang Nucleosynthesis (BBN) and confront its predictions, and the constraints that emerge from them, with those derived from independent observations of the Universe at much later epochs. Following an overview of the key physics that controls the synthesis of the elements in the early Universe, the predictions of BBN in the standard (and some nonstandard) models of cosmology and particle physics are presented. The observational data used to infer the primordial abundances are described, with an emphasis on the distinction between precision and accuracy. These are compared with the predictions, testing the internal consistency of BBN and enabling a comparison of the BBN-inferred constraints with those derived from the cosmic microwave background radiation and large scale structure data.