Photoexcitation of the quasi-bound isobar nuclear state of a nucleus in the (γ,πN) reaction

Abstract

The data from three experiments performed on the Saclay linac, at the Tomsk synchrotron, and at the MAMI accelerator in Maintz, in which single pion photoproduction on light nuclei was accompanied by the emission of nucleons, are analyzed. The behavior of the experimental cross sections, which cannot be explained in the impulse approximation, is interpreted in a model where an intermediate quasi-bound isobar nuclear state is formed and decays with the emission of a pion and a nucleon.