New measurement of the3He(α,γ)7Be cross section at medium energies

Abstract

We report on a new cross-section measurement for the ${}^{3}$He($\ensuremath{\alpha}$, $\ensuremath{\gamma}$)${}^{7}$Be reaction at three medium energies of ${E}_{\mathrm{c}.\mathrm{m}.}$ between 1 and 3 MeV. The interest stems from the significant role played by the reaction in calculating an accurate solar neutrino flux and the primordial ${}^{7}$Li abundance. The energy dependence of the astrophysical ${S}_{34}$ factor observed in the present work, especially above 1 MeV, highlights the need to constrain theories in order to obtain a precise extrapolated value for ${S}_{34}(0)$. In this context, a comparison with the recent theoretical work in a fully microscopic fermionic molecular dynamics approach and a few other representative calculations emphasize the need for further experimental as well as theoretical work to resolve the existing conflicts.