Two-Photon Exchange in Electron-Proton Elastic Scattering: Theory Update

Abstract

Recent theoretical developments in the studies of two-photon exchange effects in elastic electron-proton scattering are reviewed. Two-photon exchange mechanism is considered a likely source of discrepancy between polarized and unpolarized experimental measurements of the proton electric form factor at momentum transfers of several GeV${}^2$. This mechanism predicts measurable effects that are currently studied experimentally.

Comments: 9 pages, 4 figures; To appear in Proceedings of International Workshop on Exclusive Reactions at High Momentum Transfer, May 21-24, 2007, Jefferson Lab, Newport News, VA