Can quarkonia survive deconfinement?

Abstract

We study quarkonium correlators and spectral functions at zero and finite temperature in QCD with only heavy quarks using potential models combined with perturbative QCD. First, we show that this approach can describe the quarkonium correlation function at zero temperature. Using a class of screened potentials based on lattice calculations of the static quark-antiquark free energy we calculate spectral functions at finite temperature. We find that all quarkonium states, with the exception of the 1S bottomonium, dissolve in the deconfined phase at temperatures smaller than 1.5Tc, in contradiction with the conclusions of recent studies. Despite this the temperature dependence of the quarkonium correlation functions calculated on the lattice is well reproduced in our model. We also find that even in the absence of resonances the spectral function at high temperatures is significantly enhanced over the spectral function corresponding to free quark antiquark propagation.

Dissociation of quarkonium in a complex potential

“…Thus the in-medium behavior of heavy quark bound states is used to probe the state of matter in QCD thermodynamics. 3 …”

“…The remaining function in the imaginary part of the potential associated with the linear term (67) can similarly be separated into θ r -dependent and independent terms: 3 1 − 2 sin zr zr − 3 cos(zr) (zr) 2 + 3 sin(zr) (zr) 3 +3 sin zr zr + 3 cos(zr) (zr) 2 − 3 sin(zr) (zr) 3 cos 2 θ r ≡ ψ (1) 2 (r) + ψ (2) 2 (r, θ r ),…”

“…The assumption behind the proposal is that the medium effects can be envisaged through 1 binoyfph@iitr.ac.in a temperature-dependent heavy quark potentials and have been studied over the decades either phenomenologically or through lattice based free-energy calculations [3,4]. In recent years there have been important theoretical developments in heavy quarkonium physics where a sequence of effective field theories (EFT) [5,6,7,8,9] are derived by exploiting the hierarchy of different scales of heavy quark bound state: m Q ≫ m Q v ≫ m Q v 2 , due to its large quark mass (m Q ).…”

“…In principle it is possible to study the problem of quarkonium dissolution without any use of potential models. Recently a lot of progress has been made in this direction in which the in-medium properties of different quarkonium states are encoded in spectral functions in terms of the Euclidean meson correlation functions constructed on the lattice [18,19,20,21,22,23,24,25,26]. However, the reconstruction of the spectral functions from the lattice meson correlators turns out to be very difficult, and despite several attempts its outcome still remains inconclusive.…”

Overview of quarkonium production in heavy-ion collisions at LHC

“…The heavy quarkonia are generated in early stage of the collision due to their large masses and expected to be sequentially resolved by color Debye screening at different temperatures, depending on their binding energies, during evolution [1]. Therefore, the data on the yields and momentum spectra of quarkonia may provide invaluable information on the medium temperature and the characteristics of quantum chromodynamics (QCD) in high density and temperature environment [2].…”