Hadronic transport coefficients from the linear sigma model at finite temperature

TL;DR

This paper calculates hadronic transport coefficients at finite temperature using the linear sigma model, comparing different methods and analyzing the effects of in-medium masses on these coefficients.

Contribution

It introduces a comprehensive framework for computing transport coefficients in the linear sigma model at finite temperature, including novel comparisons of methods and in-medium mass effects.

Findings

Bulk viscosity over entropy density $\

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Abstract

We investigate general frameworks for calculating transport coefficients for quasiparticle theories at finite temperature. Hadronic transport coefficients are then computed using the linear sigma model (LSM). The bulk viscosity over entropy density ($\zeta/s$) is evaluated in the relaxation time approximation (RTA) and the specific shear viscosity ($\eta/s$) and static electrical conductivity ($\sigma_{el}/T$) are both obtained in the RTA and using a functional variational approach. Results are shown for different values of the scalar-isoscalar hadron vacuum mass with in-medium masses for the interacting fields. The advantages and limitations of the LSM for studies of strongly interacting matter out of equilibrium are discussed and results are compared with others in the literature.