Estimate of Two-Photon Exchange in Elastic Electron-Proton Scattering: 
QCD factorisation approach 

Nikolai Kivel
Ruhr University, Bochum, Germany and Petersburg NPI, Russia

We estimate the TPE exchange contribution to elastic electron-proton
scattering at large momentum transfer Q^2 using QCD factorisation approach.
Using several models for the nucleon distribution amplitudes, we provide
estimates for existing data and ongoing experiments.