# Viscous coefficients and thermal conductivity of a $\pi K N$ gas mixture in the medium

## TL;DR

This paper investigates the temperature and density dependence of transport coefficients like viscosity and thermal conductivity in a hot, dense pion-kaon-nucleon gas, incorporating in-medium effects for more accurate modeling.

## Contribution

It introduces in-medium cross-sections derived from thermal field theory, providing more realistic calculations of transport properties in a hadronic gas.

## Key findings

- Significant deviations in viscosity and conductivity with in-medium effects
- Shear viscosity to entropy ratio aligns with existing estimates
- Temperature dependence of transport coefficients shows notable differences from vacuum-based calculations

## Abstract

The temperature and density dependence of the relaxation times, thermal conductivity, shear viscosity and bulk viscosity for a hot and dense gas consisting of pions, kaons and nucleons have been evaluated in the kinetic theory approach. The in-medium cross-sections for $\pi\pi$, $\pi K$ and $\pi N$ scatterings were obtained by using complete propagators for the exchanged $\rho$, $\sigma$, $K^*$ and $\Delta$ excitations derived using thermal field theoretic techniques. Notable deviations can be observed in the temperature dependence of $\eta$, $\zeta$ and $\lambda$ when compared with corresponding calculations using vacuum cross-sections usually employed in the literature. The value of the specific shear viscosity $\eta/s$ is found to be in agreement with available estimates.