Exclusive production of quarkonia as a probe of the GPD E for gluons

TL;DR

This paper investigates how exclusive quarkonium production can be used to probe the gluon GPD E, providing insights into the nucleon's spin structure through theoretical modeling and potential experimental measurements at future colliders.

Contribution

It offers a novel analysis of the gluon GPD E via quarkonium production, including model-based estimates of spin asymmetries for upcoming Electron Ion Collider experiments.

Findings

Estimated transverse target spin asymmetry for various GPD E models

Potential to measure recoil nucleon polarization

Implications for understanding gluon contributions to nucleon spin

Abstract

Exclusive quarkonium photo- and electro-production off the nucleon is studied in the framework of generalized parton distributions (GPDs). The short distance part of the process is treated at leading order in perturbative Quantum Chromodynamics. The main focus is on the GPD E for gluons. On the basis of different models for E we estimate the transverse target spin asymmetry for typical kinematics of a future Electron Ion Collider. We also explore the potential of measuring the polarization of the recoil nucleon.