Regge Exchange Contribution to Deeply Virtual Compton Scattering

TL;DR

This paper demonstrates that Regge exchanges dominate Deeply Virtual Compton Scattering at low Mandelstam-t, emphasizing the meson cloud's role over quark structure and proposing process-dependent Regge amplitudes for better description.

Contribution

It introduces Regge exchange contributions into the collinear factorization framework for DVCS, highlighting their importance over universal GPDs in certain kinematic regions.

Findings

Regge exchanges describe low-t exclusive reactions effectively.

DVCS is more sensitive to the meson cloud than quark structure.

Process-dependent Regge amplitudes outperform universal GPDs in some regimes.

Abstract

Recently we have shown that exclusive QCD photon-induced reactions at low Mandelstam-t are best described by Regge exchanges in the entire scaling region, and not only for low values of Bjorken-x. In this paper we explore this crucial Regge behavior in Deeply Virtual Compton Scattering from the point of view of collinear factorization, with the proton tensor written in terms of Generalized Parton Distributions, and we reproduce this feature. Thus it appears that in the Bjorken limit, a large class of hard, low-t exclusive processes are more sensitive to the meson cloud of the proton than to its fundamental quark structure. These process will then be described most efficiently by process-dependent Regge Exclusive Amplitudes rather than by universal Generalized Parton Distributions. We introduce such Regge Exclusive Amplitudes for Deeply Virtual Compton Scattering.