# Quark Matter 2019 - the XXVIIIth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions

3-9 November 2019
Wanda Reign Wuhan Hotel
Asia/Shanghai timezone

## Collision-system dependence of charge separation relative to the second- and third-order event planes; Implications for the Chiral Magnetic Effect in STAR

4 Nov 2019, 17:40
20m
Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

#### Wanda Han Show Theatre & Wanda Reign Wuhan Hotel

Poster Presentation Chirality, vorticity and spin polarization

### Speaker

Niseem Abdelrahman (University of Illinois at Chicago)

### Description

Validation of the Chiral Magnetic Effect (CME) in the quark-gluon plasma (QGP) produced in heavy-ion collisions can provide key insights into anomalous transport in QGP and the connections between chiral symmetry restoration, axial anomaly and gluonic topology. Recently, a charge-sensitive correlator, $\mathrm{R_{\Psi_m}(\Delta S)}$ [1], designed to discern between background- and CME-driven charge separation was used to carry out a detailed set of charge separation measurements, relative to both the $2^{\mathrm{nd}}$- ($\Psi_2$) and $3^{\mathrm{rd}}$-order ($\Psi_3$) event planes for several collision systems (A+A(B)). The measurements indicate nearly flat to convex $\mathrm{R_{\Psi_m}(\Delta S)}$ distributions for the measurements relative to $\Psi_3$ and those relative to $\Psi_2$ for the p(d)+Au systems, consistent with the essentially random $\vec{B}$-field orientations for these measurements. By contrast, the A+A measurements relative to $\Psi_2$ show concave-shaped $\mathrm{R_{\Psi_2}(\Delta S)}$ distributions suggestive of a CME-driven charge separation. Results for U+U collisions at $\sqrt{s_{NN}}$= 193 GeV and p(d)+Au, Cu+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV will be presented and discussed in this poster.

[1] N. Magdy, et al., Phys. Rev. C 97 (2018) 061901.

### Primary author

Niseem Abdelrahman (University of Illinois at Chicago)