Search forLi7Breakup inLi+7Au197Au near Grazing Incidence

Abstract

Coincidence measurements of charged particles emitted in a narrow cone in ${}_{}{}^7{}_{}{}^{}\mathrm{L}\mathrm{i}+$ ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, near grazing incidence, show that the two-step breakup via the ${\frac{7}{2}}^{-}$ (4.63 MeV) state in the $\alpha +t$ channel is very weak, in agreement with the predictions of the corresponding inelastic process (${\sigma }_{\mathrm{tot}}=350\mathrm{}$ μb). An important $\alpha -d$ coincidence yield comes from the following mechanism: ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$(${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^6{}_{}{}^{}\mathrm{L}\mathrm{i}*$ (2.18 MeV)) ${}_{}{}^{198}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}_{}^{*}{}_{}{}^{}\left(2.18\mathrm{} \mathrm{MeV}\right)\to \alpha +d$; ${\sigma }_{\mathrm{tot}}<~9\pm 2$ mb. The experimental optimum $Q$ value of the first step of this process is $Q_{\mathrm{opt}}=-1.8\mathrm{}\pm 0.1$ MeV.