Study of exclusive photoproduction of charmonium in ultra-peripheral lead-lead collisions

A bstract The cross-sections of exclusive (coherent) photoproduction J/ψ and ψ (2S) mesons in ultra-peripheral PbPb collisions at a nucleon-nucleon centre-of-mass energy 5 . 02 TeV are measured using data sample corresponding to an integrated luminosity 228 ± 10 μb − 1 , collected by the LHCb experiment 2018. differential separately as function transverse momentum rapidity nucleus-nucleus frame for mesons. be $$ {\sigma}_{J/\psi}^{\textrm{coh}} σ J / ψ coh = 965 0 059 232 262 mb {\sigma}_{\psi (2S)}^{\textrm{coh}} 2 S 923 086 028 040 mb, where first listed uncertainty is statistical, second systematic third due determination. cross-section ratio (2S)}^{\textrm{coh}}/{\sigma}_{J/\psi}^{\textrm{coh}} 155 014 003, statistical systematic. These results compatible with theoretical predictions.