Pion Charge-Exchange Scattering from Light Nuclei

The reactions ${}_{}{}^7{}_{}{}^{}\mathrm{Li}({\pi }^{+}, {\pi }^0){}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}({\pi }^{+}, {\pi }^{-}){}_{}{}^{10}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}({\pi }^{+}, {\pi }^0){}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ are examined using a full multiple-scattering formalism with a separable form assumed for the pion-nucleon $t$ matrix. Spin-flip contributions are included. We find that the contributions arising from transitions to nonanalog final states in the case of ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ are of the same order of magnitude as pure analog cross sections.