Low-energy direct capture in the8Li(n,γ)9Liand8B(p,γ)9Creactions

Abstract

The cross sections of the ${}^{8}\mathrm{Li}(n,\ensuremath{\gamma}{)}^{9}\mathrm{Li}$ and ${}^{8}\mathrm{B}(p,\ensuremath{\gamma}{)}^{9}\mathrm{C}$ capture reactions have been analyzed using the direct capture model. At low energies, which are the astrophysically relevant regions, the capture process is dominated by $E1$ transitions from incoming s waves to bound p states. The cross sections of both mirror reactions can be described simultaneously with consistent potential parameters, whereas previous calculations have overestimated the capture cross sections significantly. However, the parameters of the potential have to be chosen very carefully because the calculated cross section of the ${}^{8}\mathrm{Li}(n,\ensuremath{\gamma}{)}^{9}\mathrm{Li}$ reaction depends sensitively on the potential strength.