25 research outputs found
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
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
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
Analyzing the Power Spectrum of the Little Bangs
In this talk we discuss the analogy between data from heavy-ion collisions
and the Cosmic Microwave Background. We identify p_T correlations data as the
heavy-ion analogy to the CMB and extract a power-spectrum from the heavy-ion
data. We define the ratio of the final state power-spectrum to the initial
coordinate-space eccentricity as the transfer-function. From the
transfer-function we find that higher terms are suppressed and we argue
that the suppression provides information on length scales like the
mean-free-path. We make a rough estimate of the mean-free-path and find that it
is larger than estimates based on the centrality dependence of v_2.Comment: 4 pages, talk given at Hard Probes 2010, Eilat, Israe
Detecting a First-Order Transition in the QCD Phase Diagram with Baryon-Baryon Correlations
We suggest baryon-baryon correlations as an experimentally accessible
signature for a first-order phase transition between a baryon-rich phase, like
quarkyonic, and a baryon-suppressed hadronic phase in the QCD phase diagram. We
examine the consequences of baryon-rich bubble formation in an expanding medium
and show how the two-particle correlations vary in the transverse and
longitudinal direction depending on the strength of the radial flow, the bubble
temperature, and the time when the baryons are emitted.Comment: Revised published version, 6 pages in PL
Confinement and Chiral Symmetry
We illustrate why color deconfines when chiral symmetry is restored in gauge
theories with quarks in the fundamental representation, and while these
transitions do not need to coincide when quarks are in the adjoint
representation, entanglement between them is still present.Comment: 4 pages, 1 figure, proceedings of Quark Matter 200
Critical Behavior of Non Order-Parameter Fields
We show that all of the relevant features of a phase transition can be
determined using a non order parameter field which is a physical state of the
theory. This fact allows us to understand the deconfining transition of the
pure Yang-Mills theory via the physical excitations rather than using the
Polyakov loop.Comment: RevTeX, 4-pages, 1 figur