68 research outputs found
Impact of off-shell dynamics on the transport properties and the dynamical evolution of Charm Quarks at RHIC and LHC temperatures
We evaluate drag and diffusion transport coefficients comparing a
quasi-particle approximation with on-shell constituents of the QGP medium and a
dynamical quasi-particles model with off-shell bulk medium at finite
temperature T. We study the effects of the width of the particles of
the bulk medium on the charm quark transport properties exploring the range
where . We find that off-shell effects are in general quite
moderate and can induce a reduction of the drag coefficient at low momenta that
disappear already at moderate momenta, . We also
observe a moderate reduction of the breaking of the Fluctuation-Dissipation
theorem (FDT) at finite momenta.
Moreover, we have performed a first study of the dynamical evolution of HQ
elastic energy loss in a bulk medium at fixed temperature extending the
Boltzmann (BM) collision integral to include off-shell dynamics. A comparison
among the Langevin dynamics, the BM collisional integral with on-shell and the
BM extension to off-shell dynamics shows that the evolution of charm energy
when off-shell effects are included remain quite similar to the case of the
on-shell BM collision integral.Comment: 13 pages, 14 figure
Recent thermodynamic results from lattice QCD analyzed within a quasi-particle model
The thermodynamic behavior of QCD matter at high temperature is currently
studied by lattice QCD theory. The main features are the fast rise of the
energy density around the critical temperature and the large
trace anomaly of the energy momentum tensor
which hints at a strongly interacting system. Such features can be accounted
for by employing a massive quasi-particle model with a temperature-dependent
bag constant. Recent lattice QCD calculations with physical quark masses by the
Wuppertal-Budapest group have shown a slower increase of and a
smaller peak with respect to previous results from the
hotQCD collaboration. We investigate the implications of such differences from
the point of view of a quasi-particle model, also discussing light and strange
quark number susceptibilities. Furthermore, we predict the impact of these
discrepancies on the temperature-dependence of the transport properties of
matter, like the shear and bulk viscosities.Comment: 18 pages, 9 figures; version accepted in Phys. Rev.D; calculation
with relaxation time \tau \sim g^4 ln g has been adde
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