Initial eccentricity fluctuations and their relation to higher-order flow harmonics

TL;DR

This paper uses Monte Carlo simulations to analyze how initial eccentricity fluctuations in heavy ion collisions relate to higher-order flow harmonics, providing testable predictions to distinguish between models and improve understanding of quark-gluon plasma viscosity.

Contribution

It offers new predictions for flow coefficient dependencies on centrality and model type, aiding in constraining initial state models and the medium's viscosity in heavy ion collisions.

Findings

Predicted flow coefficient magnitudes and centrality dependence for different models.

Ratios of flow coefficients can distinguish between initial eccentricity models.

Constraints on the medium's specific viscosity derived from model comparisons.

Abstract

Monte Carlo simulations are used to compute the centrality dependence of the participant eccentricities ($\epsilon_{n}$) in Au+Au collisions, for the two primary models currently employed for eccentricity estimates -- the Glauber and the factorized Kharzeev-Levin-Nardi (fKLN) models. They suggest specific testable predictions for the magnitude and centrality dependence of the flow coefficients $v_n$, respectively measured relative to the event planes $\Psi_n$. They also indicate that the ratios of several of these coefficients may provide an additional constraint for distinguishing between the models. Such a constraint could be important for a more precise determination of the specific viscosity of the matter produced in heavy ion collisions.