Shadowing in low-energy photonuclear reactions

Abstract

The photonuclear reaction in the multi-GeV region occurs because of the electromagnetic and hadronic interactions. The latter originates due to the hadronic fluctuation, i.e., vector meson, of the photon. The total cross section of the reaction is shadowed because of the vector meson--nucleus (hadronic) interaction. To estimate it quantitatively, the cross section of the photonuclear reaction was calculated in the low energy region ($\ensuremath{\sim}1--3$ GeV) using the simple vector-meson dominance (SVMD) model, i.e., the low-lying vector mesons (${\ensuremath{\rho}}^{0}, \ensuremath{\omega}$, and $\ensuremath{\phi}$ mesons) were considered. The nuclear shadowing is reinvestigated using the generalized vector meson (GVMD) model, where the higher $\ensuremath{\rho}$ meson effective state (${\ensuremath{\rho}}^{\ensuremath{'}}$ meson) is taken into account along with the low-lying vector mesons. Using the GVMD model, the total cross section of the photonuclear reaction are calculated in the above mentioned energy region. The calculated results are compared with the measured spectra.