Off-shell effects in pion-nucleon Bremsstrahlung

Until this moment the πNγ reaction has been studied within the Soft Proton Approximation, where the total amplitude depends only on the elastic πN scattering T-matrix. Here we propose a dynamical model that treats the amplitude to all orders in the photon energy and thus permits to investigate the off-shell behavior of the πN interaction. In addition to obtain a total gauge invariant amplitude, two-body meson exchange currents are included. The off-shell behavior of different interactions are compared to each other and with UCLA and SIN data. This makes possible to determine the interaction where the approximations involved in the model are acceptable, or eventual problems in the behavior of interactions in the off-shell regime. (author)