Probes of the small x gluon via exclusive J/psi and Upsilon

TL;DR

This paper uses new LHC data on exclusive J/psi and Upsilon production to better constrain the low-x gluon distribution, accounting for various effects and providing predictions at different energies.

Contribution

It introduces refined constraints on the low-x gluon distribution using recent data, including skewed effects, real parts, and absorptive corrections, with predictions at NLO for various energies.

Findings

Improved constraints on low-x gluon distribution.

Predictions for exclusive J/psi and Upsilon production at multiple energies.

Inclusion of skewed effects and absorptive corrections in analysis.

Abstract

New, more precise data on diffractive J/psi photoproduction and on exclusive J/psi production in the process pp -> p + J/psi + p at the LHC allow a better constraint on the low-x gluon distribution in the domain of relatively low scales Q^2 ~ 2-6 GeV^2. We account for the `skewed' effect and for the real part of the amplitude, as well as for the absorptive corrections in the case of the exclusive process pp -> p + J/psi + p. The predictions for exclusive J/psi production at \sqrt{s}=8 and 14 TeV and for exclusive Upsilon(1S) production at 7, 8 and 14 TeV are also given. We present results at leading and next-to-leading order.