Ab initio informed evaluation of the radiative capture of protons on 7Be

Abstract

The radiative capture of protons by 7Be, which is the source of 8B that β-decays emitting the majority of higher-energy solar neutrinos measured on earth, has not yet been measured at astrophysically relevant energies. The recommended value for its zero-energy S-factor, S17(0)=20.8±(0.7)exp±(1.4)theory eV⋅b, relies on theoretical extrapolations from higher-energy measurements, a process that leads to significant uncertainty. We performed a set of first-principle (or, ab initio) calculations of the 7Be(p,γ)8B reaction to provide an independent prediction of the low-energy S-factor with quantified uncertainties. We demonstrate underlying features in the predicted S-factor allowing the combination of theoretical calculations and measurements to produce an evaluated S-factor of S17(0)=19.8±0.3 eV⋅b. We expect the calculations and uncertainty quantification process described here to set a new standard for the evaluation of light-ion astrophysical reactions.