The electroproduction of 12.3±0.7 MeV positive pions from ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, leading to low-lying states in ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$, has been measured in the angular range ${\theta }_{\pi }=30\mathrm{}°-140\mathrm{}°$ for incident electron energies $E_e=158.5-165.0\mathrm{}$ MeV. The unique character of $M3\mathrm{}$ transitions in the $p$ shell permits a direct comparison of $\frac{d^2\sigma }{d{E}_{\pi }d{\Omega }_{\pi }}$ with the analog electron scattering form factors in ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$, assuming the strong $\pi$-nucleus interaction can be neglected. For the two lowest $T=1\mathrm{}$ states, the ($e, {\pi }^{+}$) angular distributions agree with the $M3\mathrm{}$ form factors. The convective term in the $M1\mathrm{}$ form factor for the third $T=1\mathrm{}$ state is deduced from a comparison of the ($e, {\pi }^{+}$) and ($e, e^{\prime }$) data and is in good agreement with recent radiative pion capture results. The photoproduction cross section leading to the ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ ground state is estimated.

NUCLEAR REACTIONS ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}(e, {\pi }^{+})e^{\prime }{}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$; $E_e=158.5-165.0\mathrm{}$ MeV; $E_{\pi }=12.3\mathrm{}$ MeV; measured $\sigma (E_{\pi }, {\theta }_{\pi })$; ${\theta }_{\pi }=30\mathrm{}°-140\mathrm{}°$; compare to electron scattering, radiative pion capture, and photoproduction.

• Received 30 March 1982

DOI:https://doi.org/10.1103/PhysRevC.26.1610