Speaker
Description
The LHCb detector is a single-arm forward spectrometer covering the pseudorapidity range 2 < 𝜂 < 5, designed for the study of particles containing bottom or charm quark. The study of exclusive vector meson photoproduction in ultra-peripheral lead-lead collisions is essential to understand physics at low Bjorken x. In particular, coherent J/ψ and ψ(2S) mesons are promising probes of nuclear shadowing due to their sensitivity to the nuclear parton distribution function of gluons.
In this presentation, we report the measurements of the differential coherent cross section productions as a function of transverse momentum and rapidity separately for J/ψ and ψ(2S) mesons, as well as the ratio of coherent ψ(2S) to J/ψ differential cross sections as a function of rapidity. in ultra-peripheral PbPb collisions at a nucleon-nucleon centre-of-mass energy of 5.02TeV. The J/ψ and ψ(2S) mesons are reconstructed in the dimuon decay channel using a data sample collected by the LHCb experiment in 2018, corresponding to an integrated luminosity of 228±10𝜇𝑏^(−1). The comparisons with theoretical predictions are also presented.
