Speaker
Description
We refine our previous calculation of multipole amplitude $E_{0+}$ for pion photoproduction process, γN→πN. The treatment of final-state interactions is based upon an earlier analysis of pion-nucleon scattering within Hamiltonian effective field theory, supplemented by incorporating contributions from the N(1650) and the KΛ coupled channel. The contribution from the bare state corresponding to the N(1650) significantly enhances our results. Additionally, we also compute the multipole amplitude $M_{1-}$, which is of direct relevance to the Roper resonance. The results are comparable with other dynamical coupled-channel models, even though the contribution from the bare state (interpreted as a 2s excitation) in this channel is small because of its large mass.
