Dynamical quasiparticles properties and effective interactions in the sQGP

TL;DR

This paper develops a dynamical quasiparticle model for the sQGP using lattice QCD data, separating time-like and space-like quantities to derive effective interactions and mean-fields, and validates it against lattice results and dilepton production data.

Contribution

It introduces a novel approach to determine quasiparticle properties and effective interactions in the sQGP from lattice QCD, including separation of time-like and space-like components.

Findings

Effective mean-fields for gluons and quarks are derived.

The model's predictions agree with lattice QCD data.

Effective interactions are approximately independent of quark chemical potential.

Abstract

Dynamical quasiparticle properties are determined from lattice QCD along the line of the Peshier model for the running strong coupling constant in case of three light flavors. By separating time-like and space-like quantities in the number density and energy density the effective degrees of freedom in the gluon and quark sector may be specified from the time-like densities. The space-like parts of the energy densities are identified with interaction energy (or potential energy) densities. By using the time-like parton densities (or scalar densities) as independent degrees of freedom variations of the potential energy densities with respect to the time-like gluon and/or fermion densities lead to effective mean-fields for time-like gluons and quarks as well as to effective gluon-gluon, quark-gluon and quark-quark (quark-antiquark) interactions. The latter dynamical quantities are found to be approximately independent on the quark chemical potential and thus well suited for an inplementation in off-shell parton transport approaches. Results from the dynamical quasiparticle model (DQPM) in case of two dynamical light quark flavors are compared to lattice QCD calculations for the net quark density as well as for the 'back-to-back' differential dilepton production rate by $q-{\bar q}$ annihilation. The DQPM is found to pass the independent tests.