Li6(p, p′)Li6(3.56 MeV)Reaction fromEp=24.3 to 46.4MeV and the Effective Interaction

The total cross section for the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}(p, p^{\prime }){}_{}{}^6{}_{}{}^{}\mathrm{Li}\left(3.56\mathrm{} \mathrm{MeV}\right)$ reaction was measured by observing the isotropic 3.56-MeV de-excitation $\gamma$ rays in a 20-${\mathrm{cm}}^3$ Ge(Li) detector and was found to decrease slowly with energy. In a microscopic model of the reaction, this cross section depends only on the spin-isospin-dependent part $V_{11}$ of the effective interaction. At energies above 34 MeV, the data are well described by a potential, $V_{11}=\frac{V{e}^{-\alpha r}}{\alpha r}$, where the range $\frac{1}{\alpha }$ is taken to be 1.0 F, and $V=12.1\mathrm{}$ MeV. At 25 MeV, $V=11.1\mathrm{}$ MeV fits the data. The impulse approximation predicts a cross section larger than the data for the energy range of this experiment, the ratio decreasing from 2.9 at 25 MeV to 1.4 at 45 MeV. Available evidence on the spin-isospin-dependent interaction is summarized. For proton energies between 23 and 52 MeV, the strength of $V_{11}$ lies in the range 12.5±2.5 MeV and does not appear to vary with energy.