Quantification of the Chiral Magnetic Effect in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV

Abstract

The Multi-Phase Transport model, AMPT, and the Anomalous Viscous Fluid Dynamics model, AVFD, are used to assess a possible chiral-magnetically-driven charge separation ($\Delta S$) recently measured with the $R_{{\Psi }_2}(\Delta S)$ correlator in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV. The Comparison of the experimental and simulated $R_{{\Psi }_2}(\Delta S)$ distributions indicates that background-driven charge separation is insufficient to account for the measurements. The AVFD model calculations, which explicitly account for CME-driven anomalous transport in the presence of background, indicate a CME signal quantified by the $P$-odd Fourier dipole coefficient $a_1^{\prime }\approx 0.5\%$ in mid-central collisions. A similar evaluation for the $\Delta \gamma$ correlator suggests that only a small fraction of this signal ($f_{\mathrm{CME}}=\Delta {\gamma }_{\mathrm{CME}}/\Delta \gamma \approx 25\%$) is measurable with this correlator in the same collisions. The related prediction for signal detection in isobaric collisions of Ru+Ru and Zr+Zr are also presented.

Comments: 5 pages, 3 figures, submitted for publication. arXiv admin note: text overlap with arXiv:2002.07934