Structure-dependent radiative corrections to e+e−→π+π−γ in the GVMD approach

We compute the radiative corrections to the process of two-pion production in association with a hard photon in e + e − annihilation by taking into account the non-perturbative structure of the pion in the one-loop calculation. For this purpose, we adopt the generalised vector meson dominance model to insert the pion form factor in loop integrals for the treatment of final-state radiation and initial-final state interference at next-to-leading order. We compare our predictions with the results of the naive factorised scalar QED approach for experimentally relevant observables in the measurement of the e + e − → π + π − γ process. The computation extends previous results obtained for the energy scan process e + e − → π + π − and can be used to quantify the uncertainty due to the model describing the pion-photon interaction in radiative return experiments at flavour factories.