Viscosity coefficients for hadron and quark-gluon phases - Nuclear Theory

Abstract: The shear $\eta$ and bulk $\zeta$ viscosities are calculated in aquasiparticle relaxation time approximation. The hadron phase is describedwithin the relativistic mean field based model with scaled hadron masses andcouplings. The quark phase is treated in terms of the heavy quark bag modelfitted to the lattice data. A two-phase model allowing for the first orderphase transition from the hadron phase to the strongly coupled quark gluonplasma is constructed by means of the Gibbs conditions. Temperature and baryondensity dependence of the calculated viscosity-to-entropy ratios $\eta-s$,$\zeta-s$ are analyzed and compared with those obtained in other models.Special attention is paid to the behavior of viscosity coefficients near thecritical temperature, from both hadron and quark-gluon side. Effects ofresonance widths on viscosities and viscosity-to-entropy ratios are estimated.

Author: A.S. Khvorostukhin, V.D. Toneev, D.N. Voskresensky

Source: https://arxiv.org/