Suppression of non-prompt J/ψ, prompt J/ψ, and $ \Upsilon $(1S) in PbPb collisions at $ \sqrt {{{s_{\text{NN}}}}} = 2.76 $ TeV

Abstract

Yields of prompt and non-prompt J/ψ, as well as Υ(1S) mesons, are measured by the CMS experiment via their µ + µ − decays in PbPb and pp collisions at √ s NN = 2.76 TeV for quarkonium rapidity |y| < 2.4. Differential cross sections and nuclear modification factors are reported as functions of y and transverse momentum p T , as well as collision centrality. For prompt J/ψ with relatively high p T (6.5 < p T < 30 GeV/c), a strong, centrality-dependent suppression is observed in PbPb collisions, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. In the same kinematic range, a suppression of non-prompt J/ψ, which is sensitive to the in-medium b-quark energy loss, is measured for the first time. Also the low-p T Υ(1S) mesons are suppressed in PbPb collisions.

Single electron yields from semileptonic charm and bottom hadron decays inAu+Aucollisions atsNN=200GeV

“…In Pb+Pb collisions at the LHC at √ s N N = 2.76 TeV, similar momentum distribution modifications of heavy flavor electrons and D mesons have been measured [15,16]. Recently, the CMS experiment has reported first measurements of B → J/ψ [17] and b-jets [18] in Pb+Pb collisions. In contrast to this suppression pattern found in Au+Au collisions, d+Au and peripheral Cu+Cu collisions at √ s N N = 200 GeV exhibit an enhancement at intermediate electron p T in the heavy flavor electron spectrum [19,20] that must be understood in terms of a mechanism that enhances the p T spectrum, e.g.…”

Prospects for Quarkonium Measurements in p–A and A–A Collisions at the LHC

“…This production mechanism is seen as a signature of deconfinement 1 . In addition, ATLAS [20], CMS [21,22,23] and ALICE measured at larger p T stronger suppressions than ALICE at low p T . The experimentally more challenging ψ(2S) plays a crucial role to establish the physics picture of the different models and providing also discriminative power between them, see for instance in [24].…”

Measurement of the D0 Meson Production in Pb–Pb and p–Pb Collisions

“…The results obtained at LHC by ALICE [24] and CMS [25] at forward rapidity are reported in Figure 1.13(a). At forward rapidity the J/ψ R AA , defined as the ratio of the p T distribution measured in Pb-Pb collisions to that measured in pp collisions scaled by the average number of nucleon-nucleon collisions, exhibits a strong p T dependence and decreases by a factor of 2 from low p T to high p T .…”

“…Figure 1.13: (a) Transverse momentum dependence of the centrality integrated nuclear modification factor of the J/ψ p T distribution in Pb-Pb at √ s NN = 2.76 TeV with respect to pp collisions. ALICE result refer to the rapidity range 2.5 < y < 4 [24], CMS one to 1.6 < y < 2.4 [25]. (b) Dimuon invariant mass distribution from Pb-Pb data at √ s NN = 2.76 TeV.…”