A large Nc approach to the study of spin effects in low-energy electron-nucleon scattering with two-photon exchange

The transverse single-spin asymmetry in inclusive electron-nucleon scattering, e + N(ST) → e' + X, represents a pure two-photon exchange observable and is of fundamental interest for exploring higher-order QED effects in electron scattering. We compute this observable in the resonance region, where excitation of ∆ isobars occurs in both intermediate and final states. We employ a novel theoretical method based on the large-Nc limit of QCD. Our predictions could be tested in future measurements of electron-nucleon scattering with polarized targets.