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

We investigate the collision energy dependence of $\eta \mathrm{/}s$ 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 $\eta \mathrm{/}s$ at $19.6$ GeV compared to $62.4$ GeV, indicating dependence on baryon chemical potential ${\mu }_B$.