Differential cross sections for ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$($\gamma$, ${\pi }^{+}$)${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ to the ground and first excited states of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ separately and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$($\gamma$ ${\pi }^{+}$,)${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ to the sum of the four lowest-lying states in ${}_{}{}^{16}{}_{}{}^{}\mathrm{N}$ have been measured at laboratory angles of 45° and 90° for pions with kinetic energies from 80 and 210 MeV. The results, which are the first to discrete nuclear final states in the $\Delta \mathrm{}\left(1236\right)\mathrm{}$ region, are in qualitative agreement with several distorted-wave impulse-approximation calculations.

• Received 14 July 1980

DOI:https://doi.org/10.1103/PhysRevLett.45.1544