Moving Forward to Constrain the Shear Viscosity of QCD Matter.
We demonstrate that measurements of rapidity differential anisotropic flow in heavy-ion collisions can constrain the temperature dependence of the shear viscosity to entropy density ratio η/s of QCD matter. Comparing results from hydrodynamic calculations with experimental data from the RHIC, we find evidence for a small η/s≈0.04 in the QCD crossover region and a strong temperature dependence in the hadronic phase. A temperature independent η/s is disfavored by the data. We further show that measurements of the event-by-event flow as a function of rapidity can be used to independently constrain the initial state fluctuations in three dimensions and the temperature dependent transport properties of QCD matter.
Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Gabriel
G
Denicol
RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA.
Akihiko
A
Monnai
Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Björn
B
Schenke