Finite-t and target mass corrections to deeply virtual Compton scattering

TL;DR

This paper provides the first comprehensive calculation of finite-t and target mass corrections to deeply virtual Compton scattering helicity amplitudes, reducing uncertainties in QCD predictions at intermediate Q^2 values relevant for experiments.

Contribution

It introduces the first complete calculation of kinematic power corrections to DVCS helicity amplitudes, improving theoretical accuracy for experimental data analysis.

Findings

Finite-t corrections are significant and impact data interpretation.

Target mass corrections are quantitatively evaluated.

Results enhance the precision of QCD predictions at Q^2 ~ 1-10 GeV^2.

Abstract

We carry out the first complete calculation of kinematic power corrections ~t/Q^2 and ~m^2/Q^2 to the helicity amplitudes of deeply virtual Compton scattering. This result removes an important source of uncertainties in the QCD predictions for intermediate momentum transfers Q^2 ~ 1-10 GeV^2 that are accessible in the existing and planned experiments. In particular the finite-t corrections are significant and must be taken into account in the data analysis.