Angular distributions of single pion charge exchange reactions to isobaric analog states in light nuclei

Measurements of the angular distributions of the single charge exchange reactions to isobaric analog states for ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}({\pi }^{+}, {\pi }^0){}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}({\pi }^{+}, {\pi }^0){}_{}{}^{15}{}_{}{}^{}\mathrm{O}$ at 165 MeV are described. The two angular distributions are very similar. The shapes are reproduced by semiphenomeno-logical isobar-doorway calculations and by second-order coupled channels calculations. The calculated magnitudes are low by about a factor of 2. The measurements are consistent with older angle-integrated cross sections for ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$.