Measurement of the $J/\psi$ pair production cross-section in $pp$ collisions at $\sqrt{s} = 13 \,{\mathrm{TeV}}$

TL;DR

This paper reports the measurement of the $J/eta$ pair production cross-section in proton-proton collisions at 13 TeV using LHCb data, providing insights into quantum chromodynamics and validating theoretical models.

Contribution

It presents the first measurement of $J/\psi$ pair production cross-section at 13 TeV in the specified kinematic range, with detailed differential cross-sections compared to theory.

Findings

Measured cross-section: 15.2 ± 1.0 ± 0.9 nb

Differential cross-sections align with theoretical predictions

Provides data for testing QCD models

Abstract

The production cross-section of $J/\psi$ pairs is measured using a data sample of $pp$ collisions collected by the LHCb experiment at a centre-of-mass energy of $\sqrt{s} = 13 \,{\mathrm{TeV}}$, corresponding to an integrated luminosity of $279 \pm 11 \,{\mathrm{pb^{-1}}}$. The measurement is performed for $J/\psi$ mesons with a transverse momentum of less than $10 \,{\mathrm{GeV}}/c$ in the rapidity range $2.0<y<4.5$. The production cross-section is measured to be $15.2 \pm 1.0 \pm 0.9 \,{\mathrm{nb}}$. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the $J/\psi$ pair are measured and compared to theoretical predictions.