Many\u2013body effects in photoreactions of light nuclei below pion threshold

In the present paper, we discuss the reaction mechanism in photoabsorption of light nuclei below pion threshold in the frame of a self-consistent RPA theory with a Skyrme force. The role of both exchange currents in electromagnetic operators and two-body correlations in the nuclear wave function has been studied in the RPA formalism. Exchange currents in RPA calculations are related to the nucleon effective mass in the Hartree-Fock field. Comparison is made between the RPA formalism and the Gari and Hebach theory. The relative contribution of exchange currents and nuclear correlations to the photoreaction of16O is evaluated from proton threshold up to 80 MeV.E1 andE2 multipoles are included in the calculation