Interpreting the charge-dependent flow and constraining the chiral magnetic wave with event shape engineering

TL;DR

This paper proposes a novel method using Event Shape Engineering to distinguish between background effects and the chiral magnetic wave signal in charge-dependent flow measurements in heavy-ion collisions.

Contribution

It introduces the use of ESE to separate background and signal in charge asymmetry studies, enhancing the search for the chiral magnetic wave.

Findings

ESE can effectively differentiate background from CMW signals.

LCC effects can mimic CMW signals in flow measurements.

The proposed method improves experimental sensitivity to the CMW.

Abstract

The charge asymmetry (Ach) dependence of anisotropic flow serves as an important tool to search for the chiral magnetic wave (CMW) in heavy-ion collisions. However, the background effect, such as the local charge conservation (LCC) entwined with collective flow, has not yet been unambiguously eliminated in the measurement. With the help of two models, the AMPT with initial quadrupole moment and the blast wave (BW) incorporating LCC, we discuss the features of the LCC-induced and the CMW-induced correlations between Ach and the flow. More importantly, we first propose to use the Event Shape Engineering (ESE) technique to distinguish the background and the signal for the CMW study. This method would be highly desirable in the experimental search for the CMW and provides more insights for understanding the charge-dependent collective motion of the quark-gluon plasma.