Exclusive J/psi and Upsilon photoproduction and the low x gluon

TL;DR

This paper explores how exclusive production of heavy vector mesons like J/psi and Upsilon can be used to better understand small-x gluon distributions in protons, using NLO calculations in collinear factorization.

Contribution

It provides a detailed NLO calculation of J/psi and Upsilon photoproduction and discusses their potential to constrain small-x gluon PDFs in global fits.

Findings

NLO corrections differ significantly between J/psi and Upsilon production.

The processes can provide valuable constraints on small-x gluon PDFs.

Outlines how these processes could be incorporated into PDF fitting procedures.

Abstract

We discuss the potential to constrain the small-$x$ PDFs using the exclusive production of heavy vector mesons. The calculation of $J/\psi$ and $\Upsilon$ photoproduction at NLO in collinear factorisation is described. The different behaviour of the NLO corrections for $J/\psi$ and $\Upsilon$ is highlighted and we outline what might be expected from the inclusion of these processes in a PDF fit.