NLO inclusive $J/\psi$ photoproduction at large $P_T$ at HERA and the EIC

TL;DR

This paper presents a comprehensive NLO QCD analysis of inclusive $J/$ photoproduction at large transverse momentum at HERA and the EIC, including QED and charm channel contributions, and explores the potential to probe intrinsic charm in the proton.

Contribution

It provides the first reliable estimate of the EIC's capability to measure $J/$ production and detect intrinsic charm in the proton using NLO calculations.

Findings

Results agree with HERA data from H1.

Demonstrates EIC's potential to observe $J/$+charm production.

Shows sensitivity to intrinsic charm at high $x$.

Abstract

We study inclusive $J/\psi$ photoproduction at NLO at large $P_T$ at HERA and the EIC. Our computation includes NLO QCD leading-$P_T$ corrections, QED contributions via an off-shell photon as well as those from $J/\psi$+charm channels. For the latter, we employ the variable-flavour-number scheme. Our results are found to agree with the latest HERA data by H1 and provide, for the first time, a reliable estimate of the EIC reach for such a measurement. Finally, we demonstrate the observability of $J/\psi$+charm production and the sensitivy to probe the non-perturbative charm content of the proton at high $x$, also known as intrinsic charm, at the EIC.