Charge separation with fluctuating domains in relativistic heavy-ion collisions

TL;DR

This paper investigates charge separation phenomena in relativistic heavy-ion collisions, proposing a domain-based model that aligns with experimental observations and suggests small, metastable domains in the early quark-gluon plasma stage.

Contribution

It introduces a domain-based scenario with final state interactions to explain charge correlations observed in heavy-ion collisions, linking domain size and number to early quark-gluon plasma conditions.

Findings

Model reproduces STAR charge correlation measurements

Small occupancy factor indicates few metastable domains

Supports the presence of small, early-stage domains in QGP

Abstract

Charge separation induced by the chiral magnetic effect suggested that some ${\cal P}$- or ${\cal CP}$-odd metastable domains could be produced in a QCD vacuum in the early stage of relativistic heavy-ion collisions. Based on a multi-phase transport model, our results suggest that a domain-based scenario with final state interactions can describe the solenoidal tracker at RHIC detector (STAR) measurements of both same- and opposite-charge azimuthal angle correlations, $<\cos(\phi_{\alpha}+\phi_{\beta})>$, in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}=200$ GeV. The occupancy factor of the total volume of domains over the fireball volume is small, which indicates that the size and number of metastable domains should be relatively small in the early stage of a quark-gluon plasma.