Reaction mechanisms in the scattering of8Lion208Pbaround the Coulomb barrier

Abstract

We present an analysis of the reaction ${}^{8}\mathrm{Li}{+}^{208}\mathrm{Pb},$ which has been recently measured at energies around the Coulomb barrier. The study is focused on the elastic and one-neutron removal channels. The elastic angular distribution has been analyzed by means of the optical model and coupled-channels method. The measured ${}^{7}\mathrm{Li}$ yield has been assumed to come from the one-neutron transfer reaction ${}^{208}\mathrm{Pb}{(}^{8}\mathrm{Li},$ ${}^{7}\mathrm{Li}{)}^{209}\mathrm{Pb}$ and the breakup reaction ${}^{8}\mathrm{Li}{+}^{208}\mathrm{Pb}\ensuremath{\rightarrow}{n+}^{7}\mathrm{Li}{+}^{208}\mathrm{Pb}.$ For the former, an analysis in terms of the distorted wave Born approximation and coupled-channels Born approximation (CCBA) methods has been performed. For the breakup reaction, a generalization of the CCBA method has been used, in which the final states are described as ${n+}^{208}\mathrm{Pb}$ continuum states. Transfer and breakup are then treated consistently. The summed angular distribution for the two processes reproduces the shape and absolute magnitude of the measured ${}^{7}\mathrm{Li}$ distribution. We conclude that most of the measured ${}^{7}\mathrm{Li}$ yield comes from the one-neutron transfer channel. We also show that the elastic scattering is notably affected by the strong coupling to transfer channels.