Dissipative hydrodynamics coupled to chiral fields

TL;DR

This study integrates second-order dissipative hydrodynamics with chiral fields to analyze their effects on elliptic flow and related observables in relativistic heavy-ion collisions, highlighting the importance of viscosity temperature dependence.

Contribution

It introduces a self-consistent coupling of hydrodynamics with chiral fields in 2+1 dimensions, examining their impact on flow observables in heavy-ion collisions.

Findings

Elliptic flow $v_2$ is weakly affected by chiral coupling.

The temperature dependence of $ta/s$ significantly influences $v_2$.

The ratio $v_4/(v_2)^2$ is highly sensitive to both chiral coupling and $ta/s$ temperature dependence.

Abstract

Using second--order dissipative hydrodynamics coupled self-consistently to the linear $\sigma$ model we study the 2+1 dimensional evolution of the fireball created in Au+Au relativistic collisions. We analyze the influence of the dynamics of the chiral fields on the charged-hadron elliptic flow $v_2$ and on the ratio $v_4/(v_2)^2$ for a temperature-independent as well as for a temperature-dependent viscosity-to-entropy ratio $\eta/s$ calculated from the linearized Boltzmann equation in the relaxation time approximation. We find that $v_2$ is not very sensitive to the coupling of chiral sources to the hydrodynamic evolution, but the temperature dependence of $\eta/s$ plays a much bigger role on this observable. On the other hand, the ratio $v_4/(v_2)^2$ turns out to be much more sensitive than $v_2$ to both the coupling of the chiral sources and the temperature dependence of $\eta/s$.