The 8th International Conference on Chirality, Vorticity and Magnetic Field in Quantum Matter

Search for the Chiral Magnetic Effect by Event Shape Engineering Differentially in Invariant Mass in Au+Au Collisions at sNN = 200 GeV from STAR

25 juil. 2024, 17:30

30m

Amphitheater A11 (West University of Timisoara)

Talk Magnetic field and Rotation

Orateur

M. Han-Sheng Li (Purdue University)

Description

Chiral Magnetic Effect (CME) is a phenomenon in which electric charge is separated by a strong magnetic field from local domains of chirality imbalance and parity violation in quantum chromodynamics (QCD). The CME-sensitive observable, charge-dependent three-particle azimuthal correlator $\mathrm{\Delta }\gamma$, is contaminated by a major physics background proportional to the particle elliptic anisotropy ($v_2$). In this talk, we report a new analysis from STAR on charge separation using the Event Shape Engineering (ESE) approach [1], projecting $\mathrm{\Delta }\gamma$ to zero $v_2$ to obtain the intercept $\mathrm{\Delta }{\gamma }_{ESE}$ in which flow-driven background is largely suppressed. Our approach has several novel aspects: (1) we use three subevents to select dynamical fluctuations of $v_2$ by separating particles of interest from ESE selection; (2) we apply the ESE method differentially as a function of the pair invariant mass of particles of interest since CME is a low-$p_T$ phenomenon and hence more sensitive to lower mass; (3) we investigate remaining nonflow contamination in the extracted intercept [2]. We report preliminary results in Au+Au collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=200$ GeV from STAR using the event plane reconstructed with the time projection chamber (TPC) and the spectator plane reconstructed with the zero-degree calorimeter (ZDC). We compare our results to Anomalous-Viscous Fluid Dynamics (AVFD) model simulations [3].

Documents de présentation

HanSheng_Chirality_ver6.pdf