Is the chiral magnetic effect fast enough?

Abstract

While we find within holography that the lifetime of the magnetic field for collider energies like those achieved at RHIC is long enough to build up the chiral magnetic current, the lifetime of the magnetic field at LHC seems to be too short. We study the real-time evolution of the chiral magnetic effect out of equilibrium in strongly coupled holographic gauge theories. We consider the backreaction of the magnetic field onto the geometry and monitor pressure and chiral magnetic current. Our findings show that generically, at a small magnetic field, the pressure builds up faster than the chiral magnetic current, whereas at a strong magnetic field the opposite is true. At large charge, we also find that equilibration is delayed significantly due to long-lived oscillations. We also match the parameters of our model to QCD parameters and draw lessons of possible relevance to the realization of the chiral magnetic effect in heavy ion collisions. In particular, we find an equilibration time of about ∼0.35 fm/c in the presence of the chiral anomaly for plasma temperatures of order T ∼ 300–400 MeV