Measurement of prompt and nonprompt charmonium suppression in $$\text {PbPb}$$ collisions at 5.02$$\,\text {Te}\text {V}$$

Abstract

The nuclear modification factors of and mesons are measured in collisions at a centre-of-mass energy per nucleon pair of . The analysis is based on and data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 and 28, respectively. The measurements are performed in the dimuon rapidity range of as a function of centrality, rapidity, and transverse momentum ( ) from in the most forward region and up to 50. Both prompt and nonprompt (coming from b hadron decays) mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at for the two meson components. No dependence on rapidity is observed for either prompt or nonprompt mesons. An indication of a lower prompt meson suppression at is seen with respect to that observed at intermediate . The prompt meson yield is found to be more suppressed than that of the prompt mesons in the entire range.

Studies of beauty suppression via nonprompt $D^0$ mesons in PbPb collisions at 5.02 TeV withthe CMS detector

“…The vertical bands around the data points and at unity represent the bin-by-bin and global systematic uncertainties, respectively. compared with the R AA of B mesons [4], nonprompt J/ψ mesons from b hadron decays [5], prompt D 0 mesons [6], and charged hadrons [7]. The B → D 0 R AA is consistent with the B meson and nonprompt J/ψ meson results, and extends the reach of b quark related R AA studies to a larger p T coverage at midrapidity.…”

“…In Fig. 2 Global uncertainty CUJET EPOS2+MC@sHQ TAMU PHSD Figure 3: The B → D 0 nuclear modification factor R AA for PbPb collisions at √ s NN = 5.02 TeV (red circles) [2] compared to other particles [4,5,6,7] (upper panel), and to various theoretical predictions [8,9,10,11] (lower panel). The vertical bands around the data points and at unity represent the bin-by-bin and global systematic uncertainties, respectively.…”

gg → Z Z: analytic two-loop results for the low- and high-energy regions

“…It can be measured with an accuracy of a few percent (see, e.g., Ref. [1,2]) and, furthermore, plays an important role both for on-shell and off-shell Higgs boson production. The latter is particularly important in the context of the indirect determination of the Higgs boson width [3,4], as was pointed out in Refs.…”

Quarkonium production in nuclear collisions

“…Transport model calculations, including both direct and regenerated J/ψ, are shown for comparison [11,12]. Right: comparison of R AA for prompt J/ψ and ψ(2S) as a function of p T in minimum-bias Pb+Pb collisions at √ s NN = 5.02 TeV [13].…”