Probing the non-equilibrium dynamics of hot and dense QCD with dileptons
  It is argued that, in heavy ion collisions, thermal dileptons are good probes of the transport properties of the medium created in such events, and also of its early-time dynamics, usually inaccessible to hadronic observables. In this work we show that electromagnetic azimuthal momentum anisotropies do not only display a sensitivity to the shear relaxation time and to the initial shear-stress tensor profile, but also to the temperature dependence of the shear viscosity coefficient. 
Gojko Vujanovic, Jean-Francois Paquet, Gabriel S. Denicol, Matthew   Luzum, Bjoern Schenke, Sangyong Jeon, Charles Gale
nucl-th hep-ph nucl-ex