Chiral Magnetic Effect and evolution of electromagnetic field

TL;DR

This paper models the energy dependence of the Chiral Magnetic Effect (CME) in heavy-ion collisions, predicting a significant decrease at LHC energies and exploring electromagnetic influences on observable signals.

Contribution

It introduces a phenomenological model for CME energy dependence and a transport model including electromagnetic field evolution to analyze background effects.

Findings

CME predicted to be much weaker at LHC than at RHIC.

Electromagnetic fields have negligible impact on observables due to electric and magnetic field compensation.

CME effect sharply vanishes above certain collision energies.

Abstract

The energy dependence of observable two particle correlator in search for the local strong parity violation in Au+Au collisions is estimated within a simple phenomenological model. The model reproduces available RHIC data but at LHC predicts that the Chiral Magnetic effect (CME) will be about 20 times weaker than at RHIC, contrary to the first LHC measurements. In the lower energy range this effect should vanish sharply at energy somewhere above the top SPS one with agreement with the preliminary results of the Beam Energy Scan program. To elucidate CME background effects a transport HSD model including magnetic field evolution is put forward and electromagnetic dynamics at the RHIC energy is investigated. It is observed that the electromagnetic field included into the hadronic model does not influence on observables due to mutual compensation of effects of electric and magnetic fields.