Study of the $\eta-^7Be$ Interaction Near Threshold in $p-^6Li$ Fusion

We present a calculation for $\eta$ production in the $p-^6Li$ fusion near threshold including the $\eta-^7Be$ final state interaction (FSI). We consider the $^6Li$ and $^7Be$ nuclei as $\alpha-d$ and $\alpha-^3He$ clusters respectively. The calculations are done for the lowest states of $^7Be$ with $J = ({3\over2}^-, {1\over2}^-)$ resulting from the $L = $1 radial wave function. The $\eta-^7Be$ interaction is incorporated through the $\eta-^7Be$ $T-$matrix, constructed from the medium modified matrices for the $\eta-^3He$ and $\eta-\alpha$ systems. These medium modified matrices are obtained by solving few body equations, where the scattering in nuclear medium is taken into account.
Comment: To appear in the proceedings of IVth DAE-BRNS Workshop on HADRON PHYSICS, Aligarh Muslim University, Aligarh, 18-23 Feb. 2008