Dual parametrization and Abel transform tomography for twist-3 DVCS

We derive the dual parametrization for the DVCS amplitude to the twist-3 accuracy. The relation of the dual parametrization to the Abel transform tomography for amplitudes of hard exclusive processes is elaborated. We prove the dispersion relations for the twist-3 DVCS amplitude in the Wandzura–Wilczek approximation and show that the subtraction constant is given by the D-term form factor.