Search

The hadron-resonance gas (HRG) approach, used to model hadronic matter at small baryon potentials μB and finite temperature T, is extended to finite and large chemical potentials by introducing interactions between baryons in line with relativistic mean-field theory defining an interacting HRG (IHRG). Using lattice data for μB=0 as well as information on the nuclear equation of state at T=0 we constrain the attractive and repulsive interactions of the IHRG such that it reproduces the lattice equation of state at μB=0 and the nuclear equation of state at T=0 and finite μB. The formulated covariant approach is thermodynamically consistent and allows us to provide further information on the phase boundary between hadronic and partonic phases of strongly interacting matter by assuming constant thermodynamic potentials. [ABSTRACT FROM AUTHOR]

The quark susceptibility χq at zero and finite quark chemical potential provides a critical benchmark to determine the quark-gluon-plasma (QGP) degrees of freedom in relation to the results from lattice QCD (lQCD) in addition to the equation of state and transport coefficients. Here we extend the familiar dynamical quasiparticle model (DQPM) to partonic propagators that explicitly depend on the three-momentum with respect to the partonic medium at rest in order to match perturbative QCD (pQCD) at high momenta. Within the extended dynamical quasiparticle model (DQPM*) we reproduce simultaneously the lQCD results for the quark number density and susceptibility and the QGP pressure at zero and finite (but small) chemical potential μq. The shear viscosity η and the electric conductivity σe from the extended quasiparticle model (DQPM*) also turn out to be in close agreement with lattice results for μq=0. The DQPM*, furthermore, allows one to evaluate the momentum p, temperature T, and chemical potential μq dependencies of the partonic degrees of freedom also for larger μq, which are mandatory for transport studies of heavy-ion collisions in the regime 5<√sNN<10 GeV. [ABSTRACT FROM AUTHOR]

The heavy quark collisional scattering on partons of the quark gluon plasma (QGP) is studied in a quantum chromodynamics medium at finite temperature and chemical potential. We evaluate the effects of finite parton masses and widths, finite temperature T, and quark chemical potential μq on the different elastic cross sections for dynamical quasiparticles (on- and off-shell particles in the QGP medium as described by the dynamical quasiparticle model "DQPM") using the leading order Born diagrams. Our results show clearly the decrease of the qQ and gQ total elastic cross sections when the temperature and the quark chemical potential increase. These effects are amplified for finite μq at temperatures lower than the corresponding critical temperature Tc(μq). Using these cross sections we, furthermore, estimate the energy loss and longitudinal and transverse momentum transfers of a heavy quark propagating in a finite temperature and chemical potential medium. Accordingly, we have shown that the transport properties of heavy quarks are sensitive to the temperature and chemical potential variations. Our results provide some basic ingredients for the study of charm physics in heavy-ion collisions at Beam Energy Scan at RHIC and CBM experiment at FAIR. [ABSTRACT FROM AUTHOR]

The interactions of heavy quarks with the partonic environment at finite temperature T and finite quark chemical potential μq are investigated in terms of transport coefficients within the dynamical quasiparticle model (DQPM) designed to reproduce the lattice-QCD (lQCD) results (including the partonic equation of state) in thermodynamic equilibrium. These results are confronted with those of nuclear many-body calculations close to the critical temperature Tc. The hadronic and partonic spatial diffusion coefficients join smoothly and show a pronounced minimum around Tc at μq = 0 as well as at finite μq. Close to and above Tc its absolute value maTches the lQCD calculations for μq = 0. The smooth transition of the heavy-quark transport coefficients from the hadronic to the partonic medium corresponds to a crossover in line with lattice calculations, and differs substantially from perturbative-QCD calculations which show a large discontinuity at Tc. This indicates that in the vicinity of Tc dynamically dressed massive partons should be the effective degrees of freedom in the quark-gluon plasma. [ABSTRACT FROM AUTHOR]