Searcharxiv⌕ Search

arXiv subjects

Sergei Voloshin

Publications and source records attributed to Sergei Voloshin.

6 recordsLinked to original sources

Investigation of Experimental Observables in Search of the Chiral Magnetic Effect in Heavy-ion Collisions in the STAR experiment

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 decade, the experimental searches for the CME have aroused extensive interest at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The main goal of this article is to investigate three pertinent experimental approaches: the $γ$ correlator, the $R$ correlator and the signed balance functions. We will exploit both simple Monte Carlo simulations and a realistic event generator (EBE-AVFD) to verify the equivalence in the kernel-component observables among these methods and to ascertain their sensitivities to the CME signal for the isobaric collisions at RHIC.

nucl-ex↗

Chiral Magnetic Effect Task Force Report

In this report, we briefly examine the current status of the study of the chiral magnetic effect including theory and experimental progress. We recommend future strategies for resolving uncertainties in interpretation including recommendations for theoretical work, recommendations for measurements based on data collected in the past five years, and recommendations for beam use in the coming years of RHIC. We have specifically investigated the case for colliding nuclear isobars (nuclei with the same mass but different charge) and find the case compelling. We recommend that a program of nuclear isobar collisions to isolate the chiral magnetic effect from background sources be placed as a high priority item in the strategy for completing the RHIC mission.

nucl-th↗

Flow analysis with cumulants: direct calculations

Anisotropic flow measurements in heavy-ion collisions provide important information on the properties of hot and dense matter. These measurements are based on analysis of azimuthal correlations and might be biased by contributions from correlations that are not related to the initial geometry, so called non-flow. To improve anisotropic flow measurements advanced methods based on multi-particle correlations (cumulants) have been developed to suppress non-flow contribution. These multi-particle correlations can be calculated by looping over all possible multiplets, however this quickly becomes prohibitively CPU intensive. Therefore, the most used technique for cumulant calculations is based on generating functions. This method involves approximations, and has its own biases, which complicates the interpretation of the results. In this paper we present a new exact method for direct calculations of multi-particle cumulants using moments of the flow vectors.

nucl-ex↗

Effects of non-uniform acceptance in anisotropic flow measurement

Applicability of anisotropic flow measurement techniques and their extension for detectors with non-uniform azimuthal acceptance are discussed. Considering anisotropic flow measurement with two and three (mixed harmonic) azimuthal correlations we introduce a set of observables based on the x and y components of the event flow vector. These observables provide independent measures of anisotropic flow, and can be used to test self-consistency of the analysis. Based on these observables we propose a technique that explicitly takes into account the effects of non-uniform detector acceptance. Within this approach the acceptance corrections, as well as parameters which define the method applicability, can be determined directly from experimental data. For practical purposes a brief summary of the method is provided at the end.

nucl-th↗

Fluctuations in the Mixed Event Technique

A method for an evaluation of fluctuations in the mixed event technique is proposed. It is shown, that, generally, the magnitude of the fluctuations is proportional to $N^{3/4}$, where $N$ is the number of produced events, which should be compared with $N^{1/2}$ for the case of independent events. The formula eligible for the use in an analysis of experimental data is provided.

hep-ph↗