Soft-photon analysis of pion-proton bremsstrahlung

We define the soft-photon approximation consistent in its treatment of both the kinematical and dynamical aspects of bremsstrahlung. Using this consistent soft-photon approximation, we calculate ${\pi }^{\pm }p\gamma$ cross sections and obtain excellent agreement with experiment. Our results suggest that the contributions from off-mass-shell effects and resonances are small.