A Public Code for Precision Big Bang Nucleosynthesis with Improved Helium-4 Predictions

A Mathematica code (“PRIMAT”) for big bang nucleosynthesis (BBN), has been made publicly available. Its network includes more than 400 reactions with their updated thermonuclear reaction rates. In particular, it takes advantage of the recently improved weak reaction rates that include all the required theoretical corrections to reach a level of accuracy of \(10^{-4}\) on \(^4\mathrm{He}\). Once the uncertainties on the reaction rates and neutron lifetime are taken into account, we obtain \(Y_p = 0.24709 \pm 0.00017\), D/H = (\(2.459 \pm 0.036) \times 10^{-5}\) and Li/H = (\(5.623 \pm 0.247)\times 10^{-10}\).