Study of coherent $J/\psi$ production in lead-lead collisions at $\sqrt{s_{NN}} = 5 TeV$

TL;DR

This paper measures the coherent production cross-section of $J/$ mesons in ultraperipheral lead-lead collisions at 5 TeV, providing experimental data to test theoretical models of photon-induced interactions.

Contribution

It presents the first measurement of $J/$ coherent production cross-section in Pb-Pb ultraperipheral collisions at 5 TeV, with detailed comparison to phenomenological models.

Findings

Measured cross-section within $2.0<y<4.5$ is 4.45 mb with uncertainties.

Cross-section measurements in different rapidity intervals are provided.

Results are consistent with certain theoretical predictions.

Abstract

Coherent production of $J/\psi$ mesons is studied in ultraperipheral lead-lead collisions at a nucleon-nucleon centre-of-mass energy of 5 TeV, using a data sample collected by the LHCb experiment corresponding to an integrated luminosity of about $10 \mu b^{-1}$. The $J/\psi$ mesons are reconstructed in the dimuon final state and are required to have transverse momentum below 1 GeV. The cross-section within the rapidity range of $2.0 < y < 4.5$ is measured to be $4.45\pm0.24\pm0.18\pm0.58$ mb, where the first uncertainty is statistical, the second systematic and the third originates from the luminosity determination. The cross-section is also measured in $J/\psi$ rapidity intervals. The results are compared to predictions from phenomenological models.