Viscosity of hadron matter within relativistic mean-field based model with scaled hadron masses and couplings

TL;DR

This paper calculates shear and bulk viscosities of hadron matter using a relativistic mean-field model with scaled hadron properties, showing potential for low shear viscosity ratios and highlighting significant bulk viscosity in baryon-rich conditions.

Contribution

It introduces a quasiparticle relaxation time approach within a scaled hadron mass model to evaluate viscosities, comparing results with other models.

Findings

Small shear viscosity to entropy density ratio possible in hadron phase.

Large bulk viscosity observed in baryon-enriched matter.

Comparison with other models provided.

Abstract

The shear ($\eta$) and bulk ($\zeta$) viscosities are calculated in a quasiparticle relaxation time approximation for a hadron matter described within the relativistic mean-field based model with scaled hadron masses and couplings. Comparison with results of other models is presented. We demonstrate that a small value of the shear viscosity to entropy density ratio required for explaining a large elliptic flow observed at RHIC may be reached in the hadron phase. Large values of the bulk viscosity are noted in case of the baryon enriched matter.