Refined Big Bang Nucleosynthesis Constraints on ${\Omega }_{Baryon}$ and $N_{\nu }$

Abstract

We include correlations between elemental abundances in a Monte Carlo statistical analysis of BBN predictions, which, along with updated reaction rates and an improved BBN code, lead to tightened constraints on ${\Omega }_B$ and $N_{\nu }$. Observational upper limits on the primordial \he and $\mathrm{D}+{}^3\mathrm{He}$ fractions of $24\%$ (by weight) and $10^{-4}$ respectively lead to the limits: $0.015\le {\Omega }_B\le 0.070$, and $N_{\nu }\le 3.04$. The former limit appears to be incompatible with purely baryonic galactic halo dark matter, while the latter puts qualitatively new constraints on neutrinos, and physics beyond the standard model.

Comments: 13 pages, latex, 3 uuencoded figures (appended)