Differential cross sections for ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(\gamma , {\pi }^{+}){}_{}{}^{14}{}_{}{}^{}\mathrm{C}(\mathrm{g}.\mathrm{s}.\mathrm{})$ ($0^{+}$1) have been measured for an incident photon energy $E_{\gamma }=200\mathrm{}$ MeV at laboratory angles of 45°, 60°, 75°, 90°, 120°, and 140°. Momentum-space distorted-wave-impulse-approximation calculations, using a complete treatment of a one-body pion-photoproduction operator, are found to be in excellent agreement with the experimental data. The effect of the momentum-dependent terms in the nuclear photoproduction operator is observed. The reaction is found to be sensitive to input nuclear structure elements not observable in the ($e, e^{\prime }$) form-factor data.

• Received 18 February 1985

DOI:https://doi.org/10.1103/PhysRevLett.55.684