Forward–backward asymmetry in electron–positron annihilation into pion or kaon pairs revisited

Abstract

Forward–backward (charge) asymmetry in the processes of [Formula: see text] annihilation into a pair of charged pseudoscalar mesons is recalculated in the one-loop approximation. The exact dependence on the meson masses is taken into account. Results known in the literature are partially corrected. The bulk of the charge asymmetry appears due to double-photon exchange in [Formula: see text] channel. Experimental studies of the asymmetry can be used to verify the point-like approximation used in calculation of radiative corrections due to emission of photons by pions or kaons.