Updated Big Bang Nucleosynthesis Compared with<i>Wilkinson Microwave Anisotropy Probe</i>Observations and the Abundance of Light Elements

We improve Standard Big Bang Nucleosynthesis (SBBN) calculations taking into\naccount new nuclear physics analyses (Descouvemont et al. 2003). Using a\nMonte-Carlo technique, we calculate the abundances of light nuclei versus the\nbaryon to photon ratio.The results concerning omegab are compared to relevant\nastrophysical and cosmological observations. Consistency between WMAP, SBBN\nresults and D/H data strengthens the deduced baryon density and has interesting\nconsequences on cosmic chemical evolution. A significant discrepancy between\nthe calculated Li-7 deduced from WMAP and the Spite plateau is clearly\nrevealed. To explain this discrepancy three possibilities are invoked :\nuncertainties on the Li abundance, surface alteration of Li in the course of\nstellar evolution or poor knowledge of the reaction rates related to Be-7\ndestruction. In particular, the possible role of the up to now neglected\nBe-7(d,p)2He-4 and Be-7(d,alpha)Li5 reactions is considered. The impressive\nadvances in CMB observations provide a strong motivation for more efforts in\nexperimental nuclear physics and high quality spectroscopy to keep BBN in pace.\n Comment: accepted in ApJ, 22 pages, 5 figures