1303.1138 (Adam Bzdak et al.)

Contributions to the event-by-event charge asymmetry dependence for the
elliptic flow of pi^{+} and pi^{-} in heavy-ion collisions    [PDF]

Adam Bzdak, Piotr Bozek

We discuss various contributions to an event-by-event charge asymmetry dependence of pi^{+} and pi^{-} elliptic flow, recently measured by the STAR Collaboration at RHIC. It is shown that under quite general assumptions the difference between v_2^{+} and v_2^{-} at a given fluctuating value of an asymmetry parameter A is a linear function of A, as observed in the preliminary data. We further discuss two mechanisms that are qualitatively consistent with the experimental data and result in a signal of the correct order of magnitude. Finally we perform hydrodynamic calculations with local charge conservation at freeze-out and show that the observed signal can be qualitatively and partly quantitatively understood, providing a detailed test of the hydrodynamic model in heavy-ion collisions.

View original: http://arxiv.org/abs/1303.1138