Probe chiral magnetic effect with signed balance function *

Abstract

In this paper we propose a pair of observables as alternative ways to study the charge separation induced by Chiral Magnetic Effect (CME) in relativistic heavy ion collisions. They are, the out-ofplane to in-plane ratio of fluctuation of the difference between signed balance functions measured in pairs rest frame, and the ratio of it to similar measurement made in the laboratory frame. We have studied both observables with simulations including flow-related backgrounds, and for the first time we've pointed out and considered backgrounds that are related to resonance's global spin alignment. The two observables have similar positive responses to signal, and opposite, limited responses to identifiable backgrounds arising from resonance flow and spin alignment. We have also tested our observables with two realistic models, namely, a multi-phase transport (AMPT) model and anomalous-viscous fluid dynamics (AVFD) model. The two observables, when cross examined, will provide useful insights in the study of CME-induced charge separation.

Mapping the phases of quantum chromodynamics with beam energy scan

“…convex versus concave shape) of the R-correlator in response to various backgrounds [357] as well as the influence of factors like kinematic cuts, multiplicity fluctuations and eventplane resolution. Finally we note in passing a newly proposed observable to look for charge separation via signed balance function based on the idea of examining the momentum ordering of charged pairs along the out-of-plane direction [358].…”

System dependence of away-side broadening and $α$-clustering light nuclei structure effect in dihadron azimuthal correlations

“…There are two versions of AMPT: one for a string melting mechanism, in which a partonic phase is generated from excited strings in the HIJING model, and a simple quark coalescence model is used to combine the partons into hadrons; the other for the default AMPT version which only undergoes a pure hadron gas phase. AMPT model has been widely used in heavy ion collision at RHIC and LHC [43,46,[51][52][53][54] and the detailed introduction can be found therein. In the present work, we use the string-melting version AMPT.…”

Further developments of a multi-phase transport model for relativistic nuclear collisions

“…We have developed a version of the AMPT model that has corrected these problems and thus satisfies the electric charge conservation [277]. This charge-conserved version of the AMPT model has been shared with some colleagues for their recent studies of charge-dependent CME signals [278,279].…”