243 articles – 3617 Notices  [english version]
 HAL : in2p3-00086565, version 1
 arXiv : astro-ph/0401008
 Origin of Matter and Evolution of the Galaxies (OMEG03) conference, Wako : Japon
 Updated Big-Bang Nucleosynthesis compared to WMAP results
 (2004)
 From the observations of the anisotropies of the Cosmic Microwave Background (CMB) radiation, the WMAP satellite has provided a determination of the baryonic density of the Universe, \Omega_b.h^2, with an unprecedented precision. This imposes a careful reanalysis of the standard Big-Bang Nucleosynthesis (SBBN) calculations. We have updated our previous calculations using thermonuclear reaction rates provided by a new analysis of experimental nuclear data constrained by $R$-matrix theory. Combining these BBN results with the \Omega_b.h^2 value from WMAP, we deduce the light element (4He, D, 3He and 7Li) primordial abundances and compare them with spectroscopic observations. There is a very good agreement with deuterium observed in cosmological clouds, which strengthens the confidence on the estimated baryonic density of the Universe. However, there is an important discrepancy between the deduced 7Li abundance and the one observed in halo stars of our Galaxy, supposed, until now, to represent the primordial abundance of this isotope. The origin of this discrepancy, observational, nuclear or more fundamental remains to be clarified. The possible role of the up to now neglected 7Be(d,p)2\alpha and 7Be(d,\alpha)5Li reactions is considered.
 Thème(s) : Physique/Astrophysique/Cosmologie et astrophysique extra-galactiquePlanète et Univers/Astrophysique
 Lien vers le texte intégral : http://fr.arXiv.org/abs/astro-ph/0401008
 in2p3-00086565, version 1 http://hal.in2p3.fr/in2p3-00086565 oai:hal.in2p3.fr:in2p3-00086565 Contributeur : Dominique Girod <> Soumis le : Mercredi 19 Juillet 2006, 10:18:11 Dernière modification le : Mercredi 19 Juillet 2006, 10:18:26