# Revealing the collision energy dependence of $\eta/s$ in RHIC-BES Au+Au collisions using Bayesian statistics

## TL;DR

This study uses Bayesian statistics to analyze how the shear viscosity to entropy ratio ($s$) varies with collision energy in RHIC Au+Au collisions, revealing a higher s at lower energies, influenced by baryon chemical potential.

## Contribution

It introduces a Bayesian framework to quantify the energy dependence of s in heavy-ion collisions, highlighting the role of baryon chemical potential.

## Key findings

- s increases at lower collision energies.
- Bayesian analysis constrains s values with posterior distributions.
- Dependence of s on baryon chemical potential  is suggested.

## Abstract

We investigate the collision energy dependence of $\eta/s$ in a transport + viscous hydrodynamics hybrid model. A Bayesian analysis is performed on RHIC beam energy scan data for $Au+Au$ collisions at $\sqrt{s_{NN}}=19.6,39,$ and $62.4$ GeV. The resulting posterior probability distributions for the model parameters show a preference for a larger value of $\eta/s$ at $19.6$ GeV compared to $62.4$ GeV, indicating dependence on baryon chemical potential $\mu_B$.