Investigation of experimental observables in search of the chiral magnetic effect in heavy-ion collisions in the STAR experiment *

Abstract

The chiral magnetic effect (CME) is a novel transport phenomenon, arising from the interplay between quantum anomalies and strong magnetic fields in chiral systems. In high-energy nuclear collisions, the CME may survive the expansion of the quark-gluon plasma fireball and be detected in experiments. Over the past two decades, experimental searches for the CME have attracted extensive interest at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The main goal of this study is to investigate three pertinent experimental approaches: the correlator, the R correlator, and the signed balance functions. We exploit simple Monte Carlo simulations and a realistic event generator (EBE-AVFD) to verify the equivalence of the core components among these methods and to ascertain their sensitivities to the CME signal and the background contributions for the isobar collisions at the RHIC.

Experimental Status of the Chiral Magnetic Effect

“…An important study [17] was carried out to complement the isobar analysis, with the purpose of benchmarking the sensitivities of different observables using the analysis code from the isobar analysis to analyze simulated data. Of particular note, this study compared ∆γ to a measurement involving the width of the R correlator [18] and found these methods to have very similar sensitivities to a CME signal; this conclusion was bolstered by analytical work in [17] comparing these observables. I conclude that such additional observables are good tools to double-check the results from ∆γ, but we should not expect any qualitatively different conclusions or better sensitivity to come from them.…”

The unseen: revealing the blind production procedure and experience for NP data

“…In 2018, the flexibility of the Relativistic Heavy Ion Collider (RHIC) enabled the Solenoidal Tracker at RHIC (STAR) [1] to embark on an ambitious effort to explore new physics possibilities through minute signature variations between two slightly different experimental setups, using high energy collisions of the two isobar nuclear species 96 44 Ru+ 96 44 Ru and 96 40 Zr+ 96 40 Zr [2]. If the variations could be demonstrated at a sufficient level of confidence, they would indicate the presence of the so-called Chiral Magnetic Effect, a possible explanation for the imbalance between matter and anti-matter in the known universe (see citations in Ref.…”

“…If the variations could be demonstrated at a sufficient level of confidence, they would indicate the presence of the so-called Chiral Magnetic Effect, a possible explanation for the imbalance between matter and anti-matter in the known universe (see citations in Ref. [2] for more details). Given the potential for bias toward making a landmark discovery with implications spanning multiple fields of research, the Physics Advisory Committee for RHIC issued a directive during preparations that, to bolster faith in the integrity of the research and confidence in the experimental findings, the program be conducted with analyses blind to the different species until the results were settled and ready for publication.…”

Studying chirality imbalance with quantum algorithms

“…Besides the effects of finite T and µ, the influence of a strong magnetic field B is an exciting topic relevant to phenomenology in relativistic heavy-ion collisions, where strong magnetic fields are generated in non-central collisions [12][13][14][15][16][17]. Many studies have been conducted on the effect of magnetic fields on the QCD vacuum [18][19][20][21][22][23][24], and it has been determined that magnetic fields B act as a catalyst of dynamical chiral symmetry breaking [25][26][27].…”