Decomposition of flow and nonflow in relativistic heavy-ion collisions

TL;DR

This paper introduces a data-driven method to distinguish flow-related and nonflow azimuthal correlations in heavy-ion collisions by analyzing pseudorapidity dependencies, enhancing understanding of collision dynamics.

Contribution

The paper presents a novel approach to separate flow and nonflow correlations using two- and four-particle cumulants based on eta symmetry, applicable to symmetric heavy-ion collisions.

Findings

Method successfully separates flow and nonflow correlations in simulated data.

Demonstrates the approach's effectiveness with AMPT and HIJING event generators.

Provides insights into the nature of correlations in heavy-ion collision models.

Abstract

We propose a method to separate \Delta\eta-dependent and \Delta\eta-independent azimuthal correlations using two- and four-particle cumulants between pseudo-rapidity (\eta) bins in symmetric heavy-ion collisions. The \Delta\eta-independent correlation may be dominated by harmonic flows, a global correlation to the common collision geometry. The \Delta\eta-dependent correlation can be identified as nonflow, particle correlations unrelated to the common geometry. Our method exploits the \eta symmetry of the average harmonic flows and is "data-driven." We use the AMPT and HIJING event generators to illustrate our method. We discuss the decomposed \Delta\eta-independent and \Delta\eta-dependent correlations regarding flow and nonflow in the models.