A method to include exclusive heavy vector-meson production data at small $x$ in global parton analyses

TL;DR

This paper introduces a method to incorporate exclusive heavy vector-meson production data at small x into global parton analyses, improving gluon PDF determination at NLO and exploring potential NNLO effects.

Contribution

It presents a novel approach for including exclusive heavy vector-meson data in global parton analyses, demonstrated with gluon PDF extraction at NLO.

Findings

Successful inclusion of J/ψ data from HERA and LHC in gluon PDF analysis.

Constraints on gluon distribution from Υ production data.

Discussion of potential NNLO effects via K factor adjustments.

Abstract

We propose a method which allows the inclusion of exclusive heavy vector-meson production data at low $x$ in future global parton analyses. As an example we perform a study within xFitter to determine the gluon parton distribution function (PDF) at next-to-leading order (NLO) at moderate-to-low $x$ using the measurements of exclusive $J/\psi$ production in ep and pp collisions from HERA and LHC. We further study the constraints from the corresponding $\Upsilon$ production process. We finish by discussing the possible effects at next-to-next-to-leading order (NNLO) through incorporation of a K factor for the exclusive heavy vector-meson coefficient function at NLO.