The phenomenological isobar doorway model of Kisslinger and Wang is applied to the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\gamma , {\pi }^0){}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ for photon energies between 220 and 360 MeV. The parameters of the model are determined by fitting pion elastic scattering data. Over most of thee energy range the isobar model gives a total photoproduction cross section substantially larger than distorted-wave impulse approximation with a static first order optical potential. The calculated cross sections are compared to experimental data at photon energy 250 MeV.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({\pi }^{-}, {\pi }^{-})$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\gamma , {\pi }^{\circ })$, resonance region, isobar doorway model.

• Received 19 December 1977

DOI:https://doi.org/10.1103/PhysRevC.18.1056