Finite-tand Target-Mass Corrections to Deeply Virtual Compton Scattering

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 quantum chromodynamics 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.

Dual parametrization of generalized parton distributions in two equivalent representations

“…The main ingredients for this issue are flexible phenomenological GPD models and the development of the state-of-the-art-level formalism allowing to systematically account for the next-to-leading order and kinematical twist-four corrections [93][94][95][96][97]. The global fitting procedure [35][36][37] developed within the Mellin-Barnes integral representation framework represents the up-to-present-date most consecutive approach to challenge the GPD data description.…”

Timelike vs Spacelike DVCS from JLab, Compass to Ultraperipheral Collisions and AFTER@LHC

“…Neither did we comment on recent progresses in higher twist contributions [13] nor on the effect of resummation of higher order QCD corrections [14]. The physics of generalized parton distributions is definitely a domain of work in progress, both on the theory and on the experimental side.…”

PARTONS: PARtonic Tomography Of Nucleon Software

“…Various theoretical frameworks exist that take into account e.g. the target mass and finite-t corrections [71,72], the soft-collinear resummation of DVCS [64,65], higher order effects either in the coefficient function [54][55][56][57][58] or in the evolution kernel [78][79][80][81][82]. All theoretical frameworks should work all the same with a given GPD model.…”

“…During the same period, an intense theoretical activity put DVCS under solid control. In particular we mention the full description of DVCS up to twist-3 [50][51][52][53], the computation of higher orders in the perturbative QCD expansion [54][55][56][57][58][59][60][61][62][63], the softcollinear resummation of DVCS [64,65], the discussion of QED gauge invariance [66][67][68][69][70] and the elucidation of finite-t and target mass corrections [71,72]. Variety of those existing theoretical improvements, usually developed within the model/framework preferred by the corresponding authors, also justify the need for a common framework enabling systematic comparisons.…”