Near-threshold heavy quarkonium photoproduction in a light-front spectator model

TL;DR

This paper predicts near-threshold heavy quarkonium photoproduction cross sections using a light-front gluon-spectator model, aligning well with recent experimental data and providing insights into the proton's gluonic structure.

Contribution

It introduces a novel approach combining generalized parton distributions with a light-front gluon-spectator model to accurately predict quarkonium photoproduction near threshold.

Findings

Good agreement with Jefferson Lab, SLAC, and Cornell data.

Provides insights into proton's gluon gravitational form factors.

Predicts differential and total cross sections for $J/ ext{/}\Psi$ and $ ext{Upsilon}$ photoproduction.

Abstract

The near-threshold photo- and electroproduction of heavy vector quarkonia off the proton provides direct access to its gluonic structure. In particular, the cross section for $J/\Psi$ photoproduction near threshold is governed by the proton's gluon gravitational form factors (GFFs). In this work, we employ the generalized parton distribution framework together with gluon GFFs calculated in a light-front gluon-spectator model inspired by soft-wall AdS/QCD to predict both the differential and total cross sections for near-threshold $J/\Psi$ and $\Upsilon$ photoproductions. Our results for $J/\Psi$ photoproduction show good agreement with recent experimental data from the $J/\Psi$-007 and GlueX Collaborations at Jefferson Lab, as well as with earlier measurements from SLAC and Cornell.