Two-Photon-Exchange Correction to Elastic ep Scattering in the Forward Angle Limit

The two-photon-exchange (TPE) correction to elastic ep scattering in the forward angle region is discussed based on a simple hadronic model. It is found that the correction is exactly zero in the forward angle limit. This analytical result gives a good explanation of the previous numerical results and shows the clear power behavior of the TPE correction to elastic ep scattering in the forward angle region.