S-matrix approach for pion re-scattering in 0 production

摘要

The pion re-scattering operator for pion production, obtained in time-ordered perturbation theory, is used as a reference result to study retardation effects in the exchanged pion propagator and off-shell dependencies intrinsic to production models. We found that the S-matrix construction of the re-scattering operator describes these effects well.