# Charge asymmetry dependence of the elliptic flow splitting in relativistic heavy-ion collisions

## TL;DR

This study investigates the charge asymmetry dependence of elliptic flow splitting in relativistic heavy-ion collisions, using an extended transport model, and finds that the observed positive slope is unlikely caused by the chiral magnetic wave.

## Contribution

It introduces an extended multiphase transport model with chiral kinetic equations to analyze elliptic flow splitting and challenges the chiral magnetic wave as the primary cause.

## Key findings

- Negative slope of $ riangle v_2$ with respect to charge asymmetry from simulations.
- Overestimation of spin polarization splitting by magnetic field in QGP.
- Positive experimental slope unlikely due to chiral magnetic wave.

## Abstract

The elliptic flow splitting $\Delta v_2$ between $\bar{u}$ and $u$ quarks as well as between $\pi^-$ and $\pi^+$ in midcentral Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV has been studied, based on the framework of an extended multiphase transport model with the partonic evolution described by the chiral kinetic equations of motion. Within the available statistics, the slope of $\Delta v_2$ between $\bar{u}$ and $u$ quarks with respect to the electric charge asymmetry $A_{ch}$ from the linear fit is found to be negative, due to the correlation between the velocity and the coordinate in the initial parton phase-space distribution. Simulations with the magnetic field in QGP overestimate the splitting of the spin polarization between $\Lambda$ and $\bar{\Lambda}$ observed experimentally, with the latter more consistent with results under the magnetic field in vacuum. Considering the uncertainties from the magnetic field, the quark-antiquark vector interaction, and the hadronization, as well as the hadronic evolution, our study shows that the experimentally observed positive slope of $\Delta v_2$ with respect to $A_{ch}$ is not likely due to the chiral magnetic wave.