The fate of quarkonia in heavy-ion collisions at LHC energies: a unified description of the sequential suppression patterns

Abstract

Measurements made at the LHC have shown that the production of the J/ψ, ψ(2S), Υ (1S) and Υ (2S) quarkonia is suppressed in Pb-Pb collisions, with respect to the extrapolation of the pp production yields. The ψ(2S) and Υ (2S) states are more strongly suppressed than the ground states and the level of the suppression changes with the centrality of the collision. We show that the measured patterns can be reproduced by a simple model, where all quarkonia are treated in a unified way, starting from the recent realisation that, in pp collisions, the probability of quarkonium formation has a universal dependence on the binding-energy of the bound state. The hot-medium suppression effect is parametrized by a penalty factor in the binding energy, identical for all (S-and P-wave) charmonium and bottomonium states, including those that indirectly contribute to the measured results through feed-down decays. This single parameter, computed through a global fit of all available suppression patterns, fully determines the hierarchy of nuclear effects, for all states and centrality bins. The resulting faithful description of the data provides convincing evidence in favour of the conjecture of sequential quarkonium suppression induced by QGP formation.PACS. 12.38.Aw General properties of QCD -12.38.Qk Experimental tests of QCD -12.38.Mh Quarkgluon plasma

Signatures of QGP at RHIC and the LHC

“…Fig. 11 R AA of quarkonium states as a function of the binding energy in Pb+Pb collisions at √ s NN = 2.76TeV measured by the CMS experiment, which is consistent with the sequential suppression pattern[64][65][66] …”

“…As shown in Fig. 11, R AA of charmonia, J/ψ and ψ(2S), and bottomonia, ϒ(1S) and ϒ(2S), have been measured and the sequential suppression behavior has been clearly observed at the CMS experiment [64][65][66] which supports the assumption of QGP formation. For quantitative understanding, further theoretical and experimental studies are needed.…”

A technique to study the elastic and inelastic interaction of quarkonium with hadrons using femtoscopic correlations

“…They demonstrated that the binding potential of c and c quarks will be screened in the partonic matter, which would cause a suppression of J/ψ meson production (per nucleon-nucleon collision) in heavy-ion reactions with respect to yield in nucleonnucleon interactions. The same argument applies to other members of the charmonium and bottomonium families [4], however the suppression of a given state depends on the energy density (hence temperature) of the partonic matter. Thus, simultaneous measurement of the production of J/ψ, ψ(2s), ϒ (1S),ϒ (2S),ϒ (3S) and other quarkonium states could provide information about thermodynamic properties of the QGP within this paradigm.…”

From prompt to direct $$\mathrm{J}/\psi $$ production: new insights on the $$\chi _{{c}1} $$ and $$\chi _{{c}2} $$ polarizations and feed-down contributions from a global-fit analysis of mid-rapidity LHC data

“…This uncertainty also blurs the pattern of how the production of quarkonia of different masses, binding energies and quantum numbers is modified by the QCD medium produced in high-energy heavy-ion collisions [31]. Indeed, the feeddown fractions from heavier states are a crucial ingredient in the observation of signatures of the sequential suppression mechanism, according to which the production rate of quarkonium states should be progressively suppressed, as the temperature of the medium increases, following a hierarchy in the binding energy of the state [32,33].…”