Tomography for amplitudes of hard exclusive processes

TL;DR

This paper explores how the amplitude of hard exclusive processes reveals specific information about the structure of hadrons through Generalized Parton Distributions, including new insights into their dual parametrization.

Contribution

It introduces a method to extract partial information about GPDs from process amplitudes and derives explicit equations linking data to the hadron's response to arbitrary spin operators.

Findings

Partial GPD image contains direct info on hadron response to quark-antiquark operators.

Derived equations connect GPD data to hadron structure.

Presented new results on dual parametrization of GPDs.

Abstract

We discuss which part of information about hadron structure encoded in the Generalized Parton Distributions (GPDs) [part of total GPD image] can be restored from the known amplitude of a hard exclusive process. The physics content of this partial image is analyzed. Among other things, we show that this partial image contains direct information about how the target hadron responses to the (string) quark-antiquark operator of {\it arbitrary} spin J. Explicit equations relating physics content of the partial image of GPDs directly to the data are derived. Also some new results concerning the dual parametrization of GPDs are presented.