Isospin Effects in Pion Single-Charge-Exchange Reactions

The (${\pi }^{\pm }, {\pi }^0$) reactions were studied on targets of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ at 160 MeV by measuring the energy spectra of the neutral pions at several laboratory angles between 6° and 160°. The shapes of the energy spectra, the angular distributions, and the ratios of cross sections for isotopic pairs are used to infer the isospin dependence of the $\Delta$-nucleus interaction.