CMS-PAS-HIN-21-007

CMS-PAS-HIN-21-007
Observation of the $\Upsilon$ (3S) meson and sequential suppression of $\Upsilon$ states in PbPb collisions at $\sqrt{\smash[b]{s_{_{\mathrm{NN}}}}}=$ 5.02 TeV
CMS Collaboration
April 2022

Abstract: The production of $\Upsilon$ (2S) and $\Upsilon$ (3S) mesons in lead-lead (PbPb) and proton-proton (pp) collisions is studied using the CMS detector at the LHC. Their nuclear modification factors, $R_{\textrm{AA}}$ , derived from the ratio of yields measured in PbPb to pp collisions, are reported as functions of transverse momentum and PbPb collision centrality. The $\Upsilon$ (3S) meson is observed for the first time in PbPb collisions. The suppression is found to be stronger for $\Upsilon$ (3S) mesons compared to $\Upsilon$ (2S) mesons, extending the pattern of sequential suppression of bottomonium states in nuclear collisions previously seen for the $\Upsilon$ (1S) and $\Upsilon$ (2S) states. The results provide new constraints on models describing the dynamics of quarkonium states in heavy ion collisions.
Links: CDS record (PDF) ; Physics Briefing ; CADI line (restricted) ; These preliminary results are superseded in this paper, PRL 133 (2024) 022302. The superseded preliminary plots can be found here.

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