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

Niseem Magdy; Mao Wu Nie; Guo Liang Ma; Roy A. Lacey

doi:10.1016/j.physletb.2020.135771

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

Niseem Magdy
, Mao Wu Nie
, Guo Liang Ma
, Roy A. Lacey

Chemistry

Stony Brook University

University of Illinois at Chicago
Shandong University
Fudan University
Chinese Academy of Sciences

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

A Multi-Phase Transport (AMPT) model is used to study the detection sensitivity of two of the primary correlators – Δγ and R_Ψ₂ – 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_CME=Δγ_CME/Δγ, which renders the Δγ-correlator insensitive to values of the Fourier dipole coefficient a₁≲2.5%, that is larger than the purported signal (signal difference) for ion-ion(isobaric) collisions. By contrast, the R_Ψ₂ correlator indicates concave-shaped distributions with inverse widths (σ_{R_Ψ₂}⁻¹) that are linearly proportional to a₁, and independent of the character of the event plane used for their extraction. The sensitivity of the R_Ψ₂ correlator to minimal CME-driven charge separation in the presence of realistic backgrounds, could aid better characterization of the CME in heavy-ion collisions.

Original language	English
Article number	135771
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	809
DOIs	https://doi.org/10.1016/j.physletb.2020.135771
State	Published - Oct 10 2020

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@article{050705731312456f88c753adc7219ab9,

title = "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 – Δγ and RΨ2 – 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 fCME=ΔγCME/Δγ, which renders the Δγ-correlator insensitive to values of the Fourier dipole coefficient a1≲2.5\%, that is larger than the purported signal (signal difference) for ion-ion(isobaric) collisions. By contrast, the RΨ2 correlator indicates concave-shaped distributions with inverse widths (σRΨ2−1) that are linearly proportional to a1, and independent of the character of the event plane used for their extraction. The sensitivity of the RΨ2 correlator to minimal CME-driven charge separation in the presence of realistic backgrounds, could aid better characterization of the CME in heavy-ion collisions.",

author = "Niseem Magdy and Nie, \{Mao Wu\} and Ma, \{Guo Liang\} and Lacey, \{Roy A.\}",

note = "Publisher Copyright: {\textcopyright} 2020 The Author(s)",

year = "2020",

month = oct,

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doi = "10.1016/j.physletb.2020.135771",

language = "English",

volume = "809",

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TY - JOUR

T1 - A sensitivity study of the primary correlators used to characterize chiral-magnetically-driven charge separation

AU - Magdy, Niseem

AU - Nie, Mao Wu

AU - Ma, Guo Liang

AU - Lacey, Roy A.

PY - 2020/10/10

Y1 - 2020/10/10

N2 - A Multi-Phase Transport (AMPT) model is used to study the detection sensitivity of two of the primary correlators – Δγ and RΨ2 – 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 fCME=ΔγCME/Δγ, which renders the Δγ-correlator insensitive to values of the Fourier dipole coefficient a1≲2.5%, that is larger than the purported signal (signal difference) for ion-ion(isobaric) collisions. By contrast, the RΨ2 correlator indicates concave-shaped distributions with inverse widths (σRΨ2−1) that are linearly proportional to a1, and independent of the character of the event plane used for their extraction. The sensitivity of the RΨ2 correlator to minimal CME-driven charge separation in the presence of realistic backgrounds, could aid better characterization of the CME in heavy-ion collisions.

AB - A Multi-Phase Transport (AMPT) model is used to study the detection sensitivity of two of the primary correlators – Δγ and RΨ2 – 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 fCME=ΔγCME/Δγ, which renders the Δγ-correlator insensitive to values of the Fourier dipole coefficient a1≲2.5%, that is larger than the purported signal (signal difference) for ion-ion(isobaric) collisions. By contrast, the RΨ2 correlator indicates concave-shaped distributions with inverse widths (σRΨ2−1) that are linearly proportional to a1, and independent of the character of the event plane used for their extraction. The sensitivity of the RΨ2 correlator to minimal CME-driven charge separation in the presence of realistic backgrounds, could aid better characterization of the CME in heavy-ion collisions.

UR - https://www.scopus.com/pages/publications/85090839196

U2 - 10.1016/j.physletb.2020.135771

DO - 10.1016/j.physletb.2020.135771

M3 - Article

SN - 0370-2693

VL - 809

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

M1 - 135771

ER -

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

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