261 research outputs found
Transverse momentum spectra and elliptic flow: Hydrodynamics with QCD-based equations of state
We present a family of equations of state within a quasiparticle model
adjusted to lattice QCD and study the impact on azimuthal flow anisotropies and
transverse momentum spectra within hydrodynamic simulations for heavy-ion
collisions at energies relevant for LHC.Comment: Aug. 2007. 3 pp. Talk given at the Focus Week of the workshop Heavy
Ion Collisions at the LHC - Last Call for Predictions, Genf, Switzerland, 29
May - 2 June 200
Viscosities in the Gluon-Plasma within a Quasiparticle Model
A phenomenological quasiparticle model, featuring dynamically generated
self-energies of excitation modes, successfully describes lattice QCD results
relevant for the QCD equation of state and related quantities both at zero and
non-zero net baryon density. Here, this model is extended to study bulk and
shear viscosities of the gluon-plasma within an effective kinetic theory
approach. In this way, the compatibility of the employed quasiparticle ansatz
with the apparent low viscosities of the strongly coupled deconfined gluonic
medium is shown.Comment: 4 pages, 1 figure. To appear in the conference proceedings for Quark
Matter 2009, March 30 - April 4, Knoxville, Tennessee, US
Plasmons, plasminos and Landau damping in a quasiparticle model of the quark-gluon plasma
A phenomenological quasiparticle model is surveyed for 2+1 quark flavors and
compared with recent lattice QCD results. Emphasis is devoted to the effects of
plasmons, plasminos and Landau damping. It is shown that thermodynamic bulk
quantities, known at zero chemical potential, can uniquely be mapped towards
nonzero chemical potential by means of a thermodynamic consistency condition
and a stationarity condition.Comment: Sep. 2007. 13 pp. Invited talk given at Zimanyi 75 Memorial Workshop
on Hadronic and Quark Matter, Budapest, Hungary, 2-4 Jul. 2007; reviewed and
published versio
Plasmons, plasminos and Landau damping in a quasiparticle model of the quark-gluon plasma
A phenomenological quasiparticle model is surveyed for 2+1 quark flavors and
compared with recent lattice QCD results. Emphasis is devoted to the effects of
plasmons, plasminos and Landau damping. It is shown that thermodynamic bulk
quantities, known at zero chemical potential, can uniquely be mapped towards
nonzero chemical potential by means of a thermodynamic consistency condition
and a stationarity condition.Comment: Sep. 2007. 13 pp. Invited talk given at Zimanyi 75 Memorial Workshop
on Hadronic and Quark Matter, Budapest, Hungary, 2-4 Jul. 2007; reviewed and
published versio
Shear and bulk viscosities of the gluon plasma in a quasiparticle description
Shear and bulk viscosities of deconfined gluonic matter are investigated
within an effective kinetic theory by describing the strongly interacting
medium phenomenologically in terms of quasiparticle excitations with
medium-dependent self-energies. We show that the resulting transport
coefficients reproduce the parametric dependencies on temperature and coupling
obtained in perturbative QCD at large temperatures and small running coupling.
The extrapolation into the non-perturbative regime results in a decreasing
specific shear viscosity with decreasing temperature, exhibiting a minimum in
the vicinity of the deconfinement transition, while the specific bulk viscosity
is sizeable in this region falling off rapidly with increasing temperature. The
temperature dependence of specific shear and bulk viscosities found within this
quasiparticle description of the pure gluon plasma is in agreement with
available lattice QCD results.Comment: Sep 2011. 24pp. 6 figures. revised journal versio
Transport Coefficients in Gluodynamics: From Weak Coupling towards the Deconfinement Transition
We study the ratio of bulk to shear viscosity in gluodynamics within a
phenomenological quasiparticle model. We show that at large temperatures this
ratio exhibits a quadratic dependence on the conformality measure as known from
weak coupling perturbative QCD. In the region of the deconfinement transition,
however, this dependence becomes linear as known from specific strongly coupled
theories. The onset of the strong coupling behavior is located near the maximum
of the scaled interaction measure. This qualitative behavior of the viscosity
ratio is rather insensitive to details of the equation of state.Comment: Oct 2011. 3 pages. 3 figures. Contribution to the proceedings of the
19th Particles and Nuclei International Conference (PANIC11
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