Extraction of the Skewing factor from the DIS/DVCS ratio

Abstract

The skewing factor, defined as the ratio of the imaginary parts of the amplitudes $Im A(\gamma^* p \to \gamma^* p)/Im A(\gamma^* p \to \gamma p)$ is extracted for the first time from the data using recent Deeply Virtual Compton Scattering (DVCS) and the inclusive inelastic cross section measurements at DESY-HERA. The results values are compared to theoretical predictions for NLO QCD and the colour dipole approach.