We analyze the role of meson exchange currents (MECs) in photon- and electron-induced one nucleon emission reactions in a fully relativistic model. The relativistic mean-field theory is used for the bound state and the Pauli reduction for the scattering state. Direct one-body and exchange two-body terms in the nuclear current are considered. Results for the ${}^{12}\mathrm{C}(\gamma ,p)$ and ${}^{16}\mathrm{O}(\gamma ,p)$ differential cross sections and photon asymmetries are displayed in an energy range between 60 and 196 MeV. The two-body seagull current affects the cross section less than in nonrelativistic analyses. In the case of the ${}^{16}\mathrm{O}(\gamma ,n)$ differential cross section, MEC effects are large but not sufficient to reproduce the data. MECs have a small effect on ${(e,e}^{\prime }p)$ calculations.

• Received 20 May 2002

DOI:https://doi.org/10.1103/PhysRevC.66.034610