Two Photon Exchange for Exclusive Pion Electroproduction

We perform detailed calculations two-photon-exchange QED corrections to the cross section of pion electroproduction. The results are obtained with and without soft-photon approximation, analytic expressions for the corrections are derived. Relative importance of the two-photon correction is analyzed for kinematics of several experiments at Jefferson Lab. A significant effect due to twophoton exchange is predicted for backward electron scattering angles and large transferred momenta.