Elisabeth Vangioni-Flam

Updated Big Bang nucleosynthesis confronted to WMAP observations and to the abundance of light elements

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

Compilation and R-matrix analysis of Big Bang nuclear reaction rates

We use the R-matrix theory to fit low-energy data on nuclear reactions involved in Big Bang nucleosynthesis. A special attention is paid to the rate uncertainties which are evaluated on statistical grounds. We provide S factors and reaction rates in tabular and graphical formats. Comment: 40 pages, accepted for publication at ADNDT, web site at http://pntpm3.ulb.ac.be/bigbang

Production and evolution of LiBeB isotopes in the Galaxy

We reassess the problem of the production of the light elements lithium, beryllium, and boron, by energetic collisions between Galactic cosmic rays (GCR) and interstellar gas nuclei, in the framework of a consistent model for the chemical evolution of our Galaxy. We propose a new scenario for the propagation of GCR in the early Galaxy suggesting that, during its halo phase, GCR were more efficiently confined than today and had flatter spectra at low energy

Constraints on the variations of the fundamental couplings

We reconsider several current bounds on the variation of the fine-structure constant in models where all gauge and Yukawa couplings vary in an interdependent manner, as would be expected in unified theories. In particular, we reexamine the bounds established by the Oklo reactor from the resonant neutron capture cross section of

Cosmic Star Formation, Reionization, and Constraints on Global Chemical Evolution

{}^{149}\mathrm{Sm}.

Lithium-6 : evolution from big bang to present

By imposing variations in

The Effects of an Early Galactic Wind on the Evolution of D,3He, and Z

{\ensuremath{\Lambda}}_{\mathrm{QCD}}

Galactic Cosmic Rays and the Evolution of Light Elements

and the quark masses, as dictated by unified theories, the corresponding bound on the variation of the fine-structure constant can be improved by about 2 orders of magnitude in such theories. In addition, we consider possible bounds on variations due to their effect on long lived \ensuremath{\alpha}- and \ensuremath{\beta}-decay isotopes, particularly

On the galactic evolution of D and He-3

{}^{147}\mathrm{Sm}

On the Baryometric Status of 3He

and