Suppression of quarkonia in PbPb collisions at $\sqrt{{s}_{{NN}}}$ = 5.02 TeV

Abstract

We study different processes responsible for the modification of quarkonia yields in the medium produced in PbPb collisions at √ s N N = 5.02 TeV. The quarkonia and heavy flavour cross sections are estimated using the measurements in pp collisions at LHC energies and shadowing corrections are obtained using the EPS09 parameterizations. A kinetic model is used which incorporates quarkonia suppression inside the Quark Gluon Plasma (QGP), suppression due to hadronic comovers, and regeneration from recombination of heavy quark pairs. The quarkonia dissociation cross section due to gluon collisions, including both color-electric dipole and colormagnetic dipole transitions, has been employed. The regeneration rate is obtained using the principle of detailed balance. The effect of these processes on the nuclear modification factors for both J/ψ and Υ in different ranges of transverse momentum p T and rapidity has been studied for PbPb collisions at √ s N N = 5.02 TeV. The calculations are compared with the available results from LHC experiments. Both the suppression and regeneration due to a QGP are effective in the low and intermediate p T range. The large observed suppression of J/ψ at p T > 10 GeV/c is larger than the suppression expected due to gluon dissociation. PACS numbers: 12.38.Mh, 24.85.+p, 25.75.-q arXiv:1909.10785v2 [hep-ph]

Production of bottomonia states in proton+proton and heavy-ion collisions

“…Figure 22 (left) depicts the calculated [24] centrality dependence of the Υ(1S) nuclear modification factor, along with the midrapidity data from CMS [18]. The calculations combined with the pion dissociation and shadowing corrections gives a very good description of the measured data.…”

“…Figure 21 (left) and (right) show the model calculation [24] of the nuclear modification factor, R AA , for the Υ(1S) and Υ(2S) respectively as a function of p T in the kinematic range covered by the ALICE detector. The ALICE data [87] is well described by the model.…”

“…experimental [16,17,18,19,20] and theoretical works [21,22,23,24] on quarkonia modifications in Pb+Pb collisions. The bottomonia states in heavy-ion collisions are suppressed with respect to their yields in proton-proton collisions scaled by the number of binary nucleon-nucleon (NN) collisions.…”

“…Figure20(left) and (right) show the calculations[24] of various contributions to the nuclear modification factor, R AA , for the Υ(1S) and Υ(2S) respectively as a function of p T compared with the mid rapidity measurements from CMS[18]. The gluon dissociation mechanism combined with the pion dissociation and shadowing corrections gives a good description of data in p T range (p T ≈ 0-15 GeV/c) for both Υ(1S) and Υ(2S).…”

Bottomonia production in p+p collisions under NRQCD formalism

“…However cold nuclear matter effects such as modification of parton distribution functions of nucleons inside nucleus also affect their yields. There have been immense experimental [3,4,5,6] and theoretical works [7,8,9,10] on quarkonia modifications in PbPb collisions for which understanding of quarkonia production in pp collisions is an important prerequisite.…”