The role of nuclear $A^{*}$ excitations for a unified description of pion induced reactions on nuclei in the medium energy range is discussed. As specific examples we treat the excitation of the $1^{+}$, $T=1\mathrm{}$ (15.11 MeV) state in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ by inelastic pion scattering and compare it with the single charge exchange reaction and the radiative capture of pions in flight into the corresponding ground states of the residual nuclei. It is shown that those reactions provide further useful tools to investigate the multipole distribution of the $A^{*}$ excitation strength and thus complement elastic pion scattering data.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\pi , {\pi }^{\prime }){}_{}{}^{12}{}_{}{}^{}\mathrm{C}(1^{+}, 15.11 \mathrm{MeV})$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({\pi }^{+}, {\pi }^0){}_{}{}^{12}{}_{}{}^{}\mathrm{N}(\mathrm{g}.\mathrm{s}.\mathrm{})$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({\pi }^{+}, \gamma ){}_{}{}^{12}{}_{}{}^{}\mathrm{N}(\mathrm{g}.\mathrm{s}.\mathrm{})$, $\Delta (3, 3)$ energy region, $A^{*}$ reaction mechanism.

• Received 13 August 1979

DOI:https://doi.org/10.1103/PhysRevC.22.681