Hydrodynamic analyses of nuclear collisions in Landau and Eckart frames

TL;DR

This paper compares the stability, causality, and observable effects of Landau and Eckart frames in second-order relativistic hydrodynamics for dense QCD matter, relevant to heavy-ion collision experiments.

Contribution

It provides a detailed analysis of how frame choice impacts hydrodynamic stability, causality, and experimental observables in relativistic dissipative models.

Findings

Frame choice affects flow observables visibly.

Limited impact on rapidity distributions.

Both frames maintain stability and causality under certain conditions.

Abstract

Relativistic dissipative hydrodynamic model at finite density is a promising tool for analyzing the dense QCD matter created in the beam energy scan experiments. The hydrodynamic frame can be chosen in the direction of energy flow, which is called the Landau frame, or conserved charge flow, which is called the Eckart frame. In this study, I investigate the stability and causality of full second-order relativistic hydrodynamic equations in the two frames. Then the effects of frame choice on hydrodynamic variables and experimental observables are estimated numerically and are found to be visible on the flow but limited on the rapidity distributions.