206 research outputs found
Can quarkonia survive deconfinement ?
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 bottomonium, dissolve in the deconfined
phase at temperatures smaller than , 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.Comment: Version accepted in Phys. Rev. D, 20 pages, 25 figure
Quarkonium states in an anisotropic QCD plasma
We consider quarkonium in a hot QCD plasma which, due to expansion and
non-zero viscosity, exhibits a local anisotropy in momentum space. At short
distances the heavy-quark potential is known at tree level from the
hard-thermal loop resummed gluon propagator in anisotropic perturbative QCD.
The potential at long distances is modeled as a QCD string which is screened at
the same scale as the Coulomb field. At asymptotic separation the potential
energy is non-zero and inversely proportional to the temperature. We obtain
numerical solutions of the three-dimensional Schroedinger equation for this
potential. We find that quarkonium binding is stronger at non-vanishing
viscosity and expansion rate, and that the anisotropy leads to polarization of
the P-wave states.Comment: 18 pages, 6 figures, final version, to appear in PR
Dissipation near the QCD phase transition
We set up a framework for field theoretical studies of systems out of thermal
equilibrium and zoom in on the dissipation of disoriented chiral condensates.
Short relaxation times are obtained in the phase transition region,
jeopardizing the definiteness of a DCC signal.Comment: 4 pages, 4 figures, espcrc.sty, to be published in the proceedings
PANIC02, Osaka, Japan, September 30 - October 4, 200
Quarkonia Correlators Above Deconfinement
We study the quarkonia correlators above deconfinement using the potential
model with screened temperature-dependent potentials. We find that while the
qualitative features of the spectral functions, such as the survival of the 1S
state, can be reproduced by potential models, the temperature dependence of the
correlators disagree with the recent lattice data.Comment: 21 pages, 26 eps figure
S-Wave Quarkonia in Potential Models
We discuss S-wave quarkonia correlators and spectral function using the
Wong-potential, and show that these do not agree with the lattice results.Comment: based on talk presented at Strangeness in Quark Matter, UCLA, March
26-31, 200
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