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

Abstract

Coherent production of $J/\ddot{I}ˆ$ 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 $10\hat{I}¼b^{-1}$. The $J/\ddot{I}ˆ$ 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 $4.45\pm 0.24\pm 0.18\pm 0.58$ 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 $J/\ddot{I}ˆ$ rapidity intervals. The results are compared to predictions from phenomenological models.

All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-013.html (LHCb public pages)