The standard and degenerate primordial nucleosynthesis versus recent experimental data

We report the results on Big Bang Nucleosynthesis (BBN) based on an updatedcode, with accuracy of the order of 0.1% on He4 abundance, compared with thepredictions of other recent similar analysis. We discuss the compatibility ofthe theoretical results, for vanishing neutrino chemical potentials, with theobservational data. Bounds on the number of relativistic neutrinos and baryonabundance are obtained by a likelihood analysis. We also analyze the effect oflarge neutrino chemical potentials on primordial nucleosynthesis, motivated bythe recent results on the Cosmic Microwave Background Radiation spectrum. TheBBN exclusion plots for electron neutrino chemical potential and the effectivenumber of relativistic neutrinos are reported. We find that the standard BBNseems to be only marginally in agreement with the recent BOOMERANG and MAXIMA-1results, while the agreement is much better for degenerate BBN scenarios forlarge effective number of neutrinos, N_\nu \sim 10.Comment: LaTeX2e, 41 pages, 20 figures. Minor changes and 4 figures slightly modifie