A sensitivity study of the primary correlators used to characterize chiral-magnetically-driven charge separation

Abstract

A Multi-Phase Transport (AMPT) model is used to study the detection sensitivity of two of the primary correlators -- $\Delta \gamma$ and $R_{{\Psi }_2}$ -- employed to characterize charge separation induced by the Chiral Magnetic Effect (CME). The study, performed relative to several event planes for different input "CME signals", indicates a detection threshold for the fraction $f_{\mathrm{CME}}=\Delta {\gamma }_{\mathrm{CME}}/\Delta \gamma$, which renders the $\Delta \gamma$-correlator insensitive to values of the Fourier dipole coefficient $a_1\lesssim 2.5\%$, that is larger than the purported signal(signal difference) for ion-ion(isobaric) collisions. By contrast, the $R_{{\Psi }_2}$ correlator indicates concave-shaped distributions with inverse widths (${\sigma }_{{\mathrm{R}}_{{\mathrm{\Psi }}_2}}^{-1}$) that are linearly proportional to $a_1$, and independent of the character of the event plane used for their extraction. The sensitivity of the $R_{{\Psi }_2}$ correlator to minimal CME-driven charge separation in the presence of realistic backgrounds, could aid better characterization of the CME in heavy-ion collisions.

7 pages, 4 figs., submitted for publication

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Cited by in corpus (4)

• Recent developments in chiral and spin polarization effects in heavy-ion collisions
• Decipher the $R_{{\Psi }_m}$ correlator in search for the chiral magnetic effect in relativistic heavy ion collisions
• An extended $R_{{\Psi }_m}^{(2)}(\Delta S_2)$ correlator for detecting and characterizing the Chiral Magnetic Wave
• Quantification of the Chiral Magnetic Effect in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=200$ GeV