Finite-t and target mass corrections in off-forward hard reactions

Abstract

We describe a systematic approach [1] to the calculation of kinematic corrections ~ t/Q^2, m^2/Q^2 in hard exclusive processes which involve momentum transfer from the initial to the final hadron state. As an example, the complete expression is derived for the time-ordered product of two electromagnetic currents that includes all kinematic corrections due to the quark distribution to twist-four accuracy. The results are applicable e.g. to the studies of deeply-virtual Compton scattering.

Comments: Invited talk at the 33rd Erice school on nuclear physics, Erici, 16-24 September 2011, Italy