Measurements of Bottomonium production in pp and PbPb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

Geonhee Oh
2019 Proceedings of International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions — PoS(HardProbes2018)   unpublished
Bottomonia are important probes of the quark-gluon plasma since they are produced at early times and propagate through the medium. The production cross sections of the three Υ states (1S, 2S, 3S) were measured by CMS in pp and PbPb collisions at √ s NN = 5.02 TeV. The nuclear modification factors, R AA , derived from the PbPb to pp ratio of yields for each state, are studied as functions of meson rapidity between 0 to 2.4 and transverse momentum p T spanning from 0 to 30 GeV/c, as well as PbPb
more » ... ollision centrality 0 to 100%. A strong suppression of is observed in PbPb collisions but the Υ(3S) was not observed clearly in PbPb collisions. The upper limit on the R AA of Υ(3S) integrated over p T , rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. The suppression of Υ(1S) is larger than that seen at √ s NN = 2.76 TeV, although the two are still compatible within uncertainties. Bottomonia are important probes of the Quark-Gluon Plasma (QGP) since they are produced at early times and propagate through the medium. The production cross sections of the three ϒ states (1S, 2S, 3S) were measured by CMS in pp and PbPb collisions at √ s NN = 5.02 TeV . The nuclear modification factors, R AA , derived from the PbPb to pp ratio of yields for each state, are studied as functions of meson rapidity between 0 to 2.4 and transverse momentum p T spanning from 0 to 30 GeV/c, as well as PbPb collision centrality 0 to 100%. A strong suppression of R AA is observed in PbPb collisions but the ϒ(3S) was not observed clearly in PbPb collisions. The upper limit on the R AA of ϒ(3S) integrated over p T , rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy-ion collisions to date. The suppression of ϒ(1S) is larger than that seen at √ s NN = 2.76 TeV, although the two are still compatible within uncertainties.
doi:10.22323/1.345.0012 fatcat:v2crrynvujcgzny4vyzgckxpwm