Next-to-leading-power kinematic corrections to DVCS: a scalar target

TL;DR

This paper derives explicit expressions for finite-$t$ and target mass corrections to DVCS helicity amplitudes up to order $1/Q^4$, demonstrating IR divergence cancellation and small nuclear effects.

Contribution

It provides the first detailed derivation of next-to-leading-power kinematic corrections to DVCS amplitudes including target mass effects.

Findings

IR divergences cancel at all orders in leading-order perturbation theory.

Target mass corrections in nuclear DVCS are small and do not affect factorization.

Explicit $1/Q^4$ power corrections to helicity amplitudes are obtained.

Abstract

Using the recent results on the contributions of descendants of the leading twist operators to the operator product expansion of two electromagnetic currents we derive explicit expressions for the kinematic finite-$t$ and target mass corrections to the DVCS helicity amplitudes to the $1/Q^4$ power accuracy. The cancellation of IR divergences for kinematic corrections is demonstrated to all powers in the leading order of perturbation theory. We also argue that target mass corrections in the coherent DVCS from nuclei are small and do not invalidate the factorization theorem.