Dynamical coupled-channels model study of pion photoproduction
The photoproduction of pions off nucleons is investigated within a dynamical coupled-channels approach based on the Julich πN model, which has been quite successful in the description of πN→πN scattering for center-of-mass energies up to 1:9 GeV. The full pion photoproduction amplitude is constructed to satisfy the generalized Ward-Takahashi identity and thus is fully gauge invariant. The calculated differential cross sections and photon spin asymmetries up to 1.65 GeV center-of-mass energy for the reactions γp→π+n, γp→π0p and γn→π−p are in good agreement with the experimental data.