Quark susceptibility in a generalized dynamical quasiparticle model

The quark susceptibility chi(q) 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 mu(q). The shear viscosity eta and the electric conductivity se from the extended quasiparticle model (DQPM*) also turn out to be in close agreement with lattice results for mu(q) = 0. The DQPM*, furthermore, allows one to evaluate the momentum p, temperature T, and chemical potential mu(q) dependencies of the partonic degrees of freedom also for larger mu(q), which are mandatory for transport studies of heavy-ion collisions in the regime 5 < root sNN < 10 GeV.