Energy spectra of pions produced by the ($p, {\pi }^{+}$) reaction on ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ leading to discrete final states have been measured with 170-210 keV resolution. Except for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, final states that can be reached by the simple transfer of a neutron tend to be favored compared to final states of more complicated structure, which is suggestive of a one-step reaction mechanism. These ($p, {\pi }^{+}$) spectra are surprisingly similar to ($d, p$) spectra at much lower momentum transfer. For ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, single-particle and 2p-1h final states are populated about equally and there is little similarity between the ($p, {\pi }^{+}$) and ($d, p$) spectra.

NUCLEAR REACTIONS ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}(p, {\pi }^{+}){}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}(p, {\pi }^{+}){}_{}{}^{12}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(p, {\pi }^{+}){}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}(p, {\pi }^{+}){}_{}{}^{14}{}_{}{}^{}\mathrm{C}$, $E_p=200\mathrm{}$ MeV; measured $\sigma \left(E_{\pi }\right)$ at ${\theta }_{\mathrm{lab}}=25\mathrm{}°$.

• Received 5 February 1980

DOI:https://doi.org/10.1103/PhysRevC.22.1348