Two-photon exchange in elastic electron-proton scattering : QCD factorization approach

Abstract

We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer $Q^2$. It is shown that the leading two-photon exchange amplitude behaves as $1/Q^4$ relative to the one-photon amplitude, and can be expressed in a model independent way in terms of the leading twist nucleon distribution amplitudes. Using several models for the nucleon distribution amplitudes, we provide estimates for existing data and for ongoing experiments.

4 pages, 4 figures

References in corpus (4)

• Global analysis of proton elastic form factor data with two-photon exchange corrections
• Two-Photon Physics in Hadronic Processes
• Perturbative QCD predictions for two-photon exchange
• Nucleon distribution amplitudes from lattice QCD