Charmonium production in pPb and PbPb collisions at 5.02 TeV with CMS

Abstract

Charmonium states, such as $J/\psi$ and $\psi\left(2S\right)$ mesons, are excellent probes of the Quark-Gluon Plasma (QGP). The understanding of charmonium production in PbPb collisions requires the inclusion of many phenomena, such as dissociation in the QGP and statistical recombination, on top of cold nuclear matter effects (modifications of nPDFs, initial-state energy loss, nuclear break-up). Measurements of charmonium production in pPb collisions are crucial in order to disentangle the QGP-related effects from cold nuclear matter effects. In these proceedings, final results on the ratio of $\psi\left(2S\right)$ meson to $J/\psi$ meson yields in PbPb collisions normalized to pp collisions at $\sqrt{s_{NN}}=5.02$ TeV, are reported. In addition, final prompt and nonprompt $J/\psi$ meson results in pPb collisions at 5.02 TeV are also shown, using the 2015 pp data taken at the same energy. At last, final results are reported regarding prompt $\psi\left(2S\right)$ meson production in pPb collisions at 5.02 TeV, as a function of rapidity.