A novel invariant mass method to isolate resonance backgrounds from the chiral magnetic effect

Abstract

The Chiral Magnetic Effect (CME) refers to charge separation along a strong magnetic field, due to topological charge fluctuations in QCD. Charge correlation ($\Delta \gamma$) signals consistent with CME have been first observed almost a decade ago. It has also been known since then that the $\Delta \gamma$ is contaminated by a major background from resonance decays coupled with elliptic flow. In this contribution, we propose differential $\Delta \gamma$ measurements as function of the pair invariant mass ($m_{\mathrm{inv}}$). The $\Delta \gamma$ in the high $m_{\mathrm{inv}}$ region is essentially free of resonance backgrounds. In the low $m_{\mathrm{inv}}$ region, the $\Delta \gamma$ backgrounds show resonance peaks. The CME signal, presumably smooth in $m_{\mathrm{inv}}$, may thus be extracted from a two-component model fit. We demonstrate the feasibility and effectiveness of this novel method by using the AMPT and toy-model Monte-Carlo simulations. We also discuss an application of the method in data analysis.

4 pages 4 figures. Quark Matter 2018 proceedings

References in corpus (7)

• Big-Bang Nucleosynthesis
• The Chiral Magnetic Effect
• Anomalous Chiral Transport in Heavy Ion Collisions from Anomalous-Viscous Fluid Dynamics
• Azimuthal correlations from transverse momentum conservation and possible local parity violation
• Search for the Chiral Magnetic Effect in Relativistic Heavy-Ion Collisions
• Measurements of the chiral magnetic effect with background isolation in 200 GeV Au+Au collisions at STAR
• Chiral magnetic effect search in p+Au, d+Au and Au+Au collisions at RHIC

Cited by in corpus (5)

• Experimental searches for the chiral magnetic effect in heavy-ion collisions
• Chiral Magnetic Effects in Nuclear Collisions
• Probe Chiral Magnetic Effect with Signed Balance Function
• Pair invariant mass to isolate background in the search for the chiral magnetic effect in Au+Au collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$= 200 GeV
• Decipher the $R_{{\Psi }_m}$ correlator in search for the chiral magnetic effect in relativistic heavy ion collisions