Measuring and interpreting charge dependent anisotropic flow

TL;DR

This paper introduces a new observable for measuring charge-dependent anisotropic flow in heavy-ion collisions, aiming to improve interpretability and distinguish effects like the Chiral Magnetic Wave from local charge conservation.

Contribution

The paper proposes a novel observable that is free from experimental inefficiencies and acceptance biases, enabling clearer interpretation of charge-dependent flow measurements.

Findings

The new observable reduces experimental uncertainties.

It helps differentiate between CMW effects and local charge conservation.

Application to data shows improved clarity in charge-dependent flow analysis.

Abstract

The Chiral Magnetic Wave (CMW) [1] predicts a dependence of the positive and negative particle elliptic flow on the event charge asymmetry. Such a dependence has been observed by the STAR Collaboration [2]. However, it is rather difficult to interpret the results of this measurement, as well as to perform cross-experiment comparisons, due to the dependence of the observable on experimental inefficiencies and the kinematic acceptance used to determine the net asymmetry. We propose another observable that is free from these deficiencies. It also provides possibilities for differential measurements clarifying the interpretation of the results. We use this new observable to study the effect of the local charge conservation that can mimic the effect of the CMW in charge dependent flow measurements.