Sharpening the Predictions of Big-Bang Nucleosynthesis

We have reexamined the nuclear inputs to big-bang nucleosynthesis using Monte Carlo realization of the cross-section data to directly estimate theoretical uncertainties for the yields of $\mathrm{D}$, ${}^3\mathrm{He}$, and ${}^7\mathrm{Li}$. Our results indicate that previous estimates of the uncertainties were too large by a factor of 2. Using the Burles–Tytler deuterium measurement, we infer a baryon density ${\Omega }_B{h}^2=0.019\mathrm{}\pm 0.0024$, predict a primeval ${}^4\mathrm{He}$ mass fraction $Y_P=0.246\mathrm{}\pm 0.0014$, and obtain a limit to the equivalent number of neutrino species $N_{\nu }<3.20\mathrm{}$ (all at $95\%$ C.L.). We also identify key reactions and the energies, where improved data would allow further progress.