Partonic Interpretation of Generalized Parton Distributions

TL;DR

This paper investigates the conditions under which generalized parton distributions can be interpreted as describing partons, revealing the necessity of gluon re-interactions for a consistent partonic picture in non-forward kinematics.

Contribution

It demonstrates that gluon mediated re-interactions are essential for a proper partonic interpretation of GPDs in non-forward kinematics at leading order.

Findings

Semi-disconnected diagrams contribute in non-forward kinematics at leading order.

Gluon re-interactions are necessary for a consistent partonic interpretation.

Partonic interpretation requires considering gluon exchanges in GPDs.

Abstract

Generalized Parton Distributions describe, within QCD factorization, the non perturbative component in the amplitudes for deeply virtual exclusive processes. However, in order for a partonic interpretation to hold, semi-disconnected diagrams should not contribute. We show that this condition is not satisfied for non-forward kinematics at leading order, and that gluon mediated re-interactions are essential for a consistent description in terms of parton degrees of freedom.