Hydrodynamic event-plane correlations in Pb+Pb collisions at   sqrt(s)=2.76ATeV
  The recently measured correlations between the flow angles associated with higher harmonics in the anisotropic flow generated in relativistic heavy-ion collisions are shown to be of hydrodynamic origin. The correlation strength is found to be sensitive to both the initial conditions and the shear viscosity of the expanding fireball medium. 
Zhi Qiu and Ulrich W. Heinz
nucl-th hep-ph nucl-ex