Recent ($\overrightarrow{p},{\pi }^{+}$) experiments on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ at 200 MeV proton bombarding energy indicate that the production asymmetry $\epsilon$ cannot be explained (within the distorted-wave Born-approximation framework) by proton distortion alone. We examine in a simple model the effect of pion rescattering from the nucleus. The dependence of $\epsilon$ on the pion wave function, as well as its sensitivity to nuclear structure and the pion production operator are studied. The implication of the large negative asymmetry observed experimentally is briefly discussed.

[NUCLEAR REACTIONS Calculated asymmetries in ($\overrightarrow{\mathrm{p}},{\pi }^{+}$) reactions on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at $T_p=200\mathrm{}$ MeV.]

• Received 27 September 1977

DOI:https://doi.org/10.1103/PhysRevC.17.837