37 research outputs found
Zero mode contribution in quarkonium correlators and in-medium properties of heavy quarks
We calculate the low energy contribution to quarkonium correlators in
Euclidean time in lattice QCD. This contribution was found to give the dominant
source of the temperature dependence of the correlators. We have found that the
low energy contribution is well described by a quasi-particle model and have
determined the effective temperature dependent heavy quark mass.Comment: Contribution to QM2008, 4 pages, LaTeX, uses iopart.cls, corrected
typo
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
Static quark anti-quark pair in SU(2) gauge theory
We study singlet and triplet correlation functions of static quark anti-quark
pair defined through gauge invariant time-like Wilson loops and Polyakov loop
correlators in finite temperature SU(2) gauge theory. We use the Luescher-Weisz
multilevel algorithm, which allows to calculate these correlators at very low
temperatures. We observe that the naive separation of singlet and triplet
states in general does not hold non-perturbatively, however, is recovered in
the limit of small separation and the temperature dependence of the
corresponding correlators is indeed very different.Comment: ReVTeX, 11 pages, 5 figure
Equation of state at finite baryon density based on lattice QCD
We employ the lattice QCD data on Taylor expansion coefficients to extend our
previous parametrization of the equation of state to finite baryon density.
When we take into account lattice spacing and quark mass dependence of the
hadron masses, the Taylor coefficients at low temperature are equal to those of
hadron resonance gas. Thus the equation of state is smoothly connected to the
hadron resonance gas equation of state at low temperatures. We also show how
the elliptic flow is affected by this equation of state at the maximum SPS
energy.Comment: 4 pages, 4 figures, Paraller talk at Quark Matter 2011, 22-28 May
2011, Annecy, Franc
Heavy Quark Diffusion from the Lattice
We study the diffusion of heavy quarks in the Quark Gluon Plasma using the
Langevin equations of motion and estimate the contribution of the transport
peak to the Euclidean current-current correlator. We show that the Euclidean
correlator is remarkably insensitive to the heavy quark diffusion coefficient
and give a simple physical interpretation of this result using the free
streaming Boltzmann equation. However if the diffusion coefficient is smaller
than , as favored by RHIC phenomenology, the transport
contribution should be visible in the Euclidean correlator. We outline a
procedure to isolate this contribution.Comment: 24 pages, 5 figure
On Fluctuations of Conserved Charges : Lattice Results Versus Hadron Resonance Gas
We compare recent lattice results on fluctuations and correlations of
strangeness, baryon number and electric charge obtained with p4 improved
staggered action with the prediction of hadron resonance gas model. We show
that hadron resonance gas can describe these fluctuations reasonably well if
the hadron properties are as calculated on the lattice.Comment: 4 pages, LaTeX, uses jpconf.cls, to appear in the proceedings of 26th
Winter Workshop on Nuclear Dynamic
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
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 in Hot Medium
I review recent progress in studying quarkonium properties in hot medium as
well as possible consequences for quarkonium production in heavy ion
collisions.Comment: Invited talk at SQM 2009, Buzios, Brazil, Sep. 27 -Oct. 2 2009,
LaTeX, 8 pages,3 figures; typos corrected, references adde
Determination of αs from the QCD static energy: An update
We present an update of our determination of the strong coupling α s from the quantum chromodynamics static energy. This updated analysis includes new lattice data, at smaller lattice spacings and reaching shorter distances, the use of better suited perturbative expressions to compare with data in a wider distance range, and a comprehensive and detailed estimate of the error sources that contribute to the uncertainty of the final result. Our updated value for α s at the Z -mass scale, M Z , is α s ( M Z ) = 0.116 6 + 0.0012 − 0.0008 , which supersedes our previous result