Gluon TMDs and inelastic $J/\psi$ leptoproduction at the EIC

TL;DR

This paper investigates the gluon Sivers function through $J/$ production in semi-inclusive deep inelastic scattering, using TMD models and NRQCD, providing predictions for future EIC experiments.

Contribution

It introduces a combined TMD and NRQCD approach to study gluon Sivers asymmetry in $J/$ production and offers predictions for EIC measurements.

Findings

Comparison with HERA and COMPASS data validates the models.

Estimates of Sivers asymmetry at EIC kinematics are provided.

The study enhances understanding of gluon spin-momentum correlations.

Abstract

We study the Sivers azimuthal asymmetry for $J/\psi$ production in semi-inclusive deep inelastic scattering, and the still poorly known gluon Sivers function. We concentrate on the $J/\psi$ low transverse momentum region, employing the transverse-momentum dependent generalised parton model (GPM), and its colour gauge invariant extension (CGI-GPM), which includes final-state interactions at leading order. We adopt the nonrelativistic QCD (NRQCD) framework for the quarkonium formation mechanism, and compare our results for the unpolarised cross section and the Sivers asymmetry with available data, respectively from HERA and COMPASS. Finally, we give estimates for the asymmetry in the kinematical regime of the future Electron-Ion Collider (EIC).