Chiral effective-field theory in the Delta(1232) region. II. Radiative pion photoproduction

We present a theoretical study of the radiative pion photoproduction on the nucleon (gamma N ->pi N gamma(')) in the Delta-resonance region, with the aim to determine the magnetic dipole moment (MDM) of the Delta(+)(1232). The study is done within the framework of chiral effective-field theory, where the expansion is performed (to next-to-leading order) in the delta power-counting scheme, an extension of chiral perturbation theory to the Delta-resonance energy region. We present the results for the absorptive part of the Delta MDM, as well as perform a sensitivity study of the dependence of gamma N ->pi N gamma(') observables on the real part of the Delta MDM. We find that an asymmetry for circular polarization of the photon beam may provide a model-independent way to measure the Delta MDM.