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

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.

Comments: 7 pages, 3 figures. Contribution to the XXVIII International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2021). Submission to SciPost Proceedings. Typo corrected