Electric charge separation in strong transient magnetic fields

Abstract

We discuss various mechanisms for the creation of an asymmetric charge fluctuation with respect to the reaction plane among hadrons emitted in relativistic heavy-ion collisions. We show that such mechanisms exist in both the hadronic gas and the partonic phases of quantum chromodynamics. The mechanisms considered here all require the presence of a strong magnetic field (the "chiral magnetic effect"), but they do not involve parity or charge-parity violations. We analyze how a transient local electric current fluctuation generated by the chiral magnetic effect can dynamically evolve into an asymmetric charge distribution among final-state hadrons in momentum space. We estimate the magnitude of the event-by-event fluctuations of the final-state charge asymmetry owing to partonic and hadronic mechanisms.