Speaker
Description
The specific shear viscosity eta/s of quark gluon plasma has been extracted with increasing accuracy from comparing viscous fluid dynamics calculations to data. Together with lattice QCD and new NLO perturbative calculations a consistent picture seems to emerge. On the other hand, for hot hadron gas below Tc uncertainties are larger, with transport models typically predicting very large eta/s up to Tc. We explore the possibility to constrain eta/s of hot hadron gas from data by utilizing the deformation of particle distributions in the presence of shear stress. Following this strategy we obtain values of the specific shear viscosity vs temperature. Results are consistent between LHC and RHIC data, and values of eta/s drop significantly between 110 and 140 MeV temperature. We make an effort to estimate the systematic uncertainties on the numbers we extract.
