Theory HEP Seminar

Mode mixing in angle and rapidity in a hydrodynamic description of heavy ion collisions

Derek Teaney

Stony Brook

We determine the non-linear hydrodynamic response to geometrical fluctuations in heavy ion collisions using ideal and viscous hydrodynamics. This response is characterized with a set of non-linear response coefficients that determine, for example, the v₅ that is produced by an ε₂ and an ε₃. These coefficients depend on viscosity in characteristic ways. We then use the linear and quadratic response to describe the observed correlations between the event plane angles.

Finally, we extend the discussion to the rapidity direction, and discuss how shape fluctuations in rapidity lead to characteristic rapidity dependent correlations. At quadratic order, these rapidity fluctuations mix with the azimuthal dependence leading to rapidity dependent azimuthal correlations, which provide an appealing explanation for the “hard-ridge”.