Resonance nucleon scattering amplitude in the photonuclear reaction

The cross section of the photonuclear reaction in the nucleon-resonance region is calculated to search the resonance-nucleon scattering amplitude in the nucleus. It is assumed that the resonance $R$ is produced and decayed in the elementary photon-nucleon $(\gamma N)$ reaction in the nucleus as $\gamma N \to R \to \gamma N$. The resonance interacts with the nucleons while propagating through the nucleus. Therefore, the calculated photonuclear reaction cross section is compared with the data to extract the resonance-nucleon scattering parameters in the nucleus.