Directed flow at mid-rapidity in event-by-event hydrodynamics
  Fluctuations in the initial geometry of a nucleus-nucleus collision have been recently shown to result in a new type of directed flow (v_1) that, unlike the usual directed flow, is also present at midrapidity. We compute this new v_1 versus transverse momentum and centrality for Au-Au collisions at RHIC using the hydrodynamic code NeXSPheRIO. We find that the event plane of v_1 is correlated with the angle of the initial dipole of the distribution, as predicted, though with a large dispersion. It is uncorrelated with the reaction plane. Our results are in excellent agreement with results inferred from STAR correlation data. 
Fernando G. Gardim, Frederique Grassi, Yogiro Hama, Matthew Luzum,   Jean-Yves Ollitrault
nucl-th hep-ph