Characterizing the hydrodynamic response to the initial conditions

TL;DR

This paper investigates how initial conditions influence the hydrodynamic evolution of particle momentum distributions, emphasizing the role of nonlinear effects in predicting flow patterns, to improve the connection between experiments and initial state models.

Contribution

It provides a quantitative analysis of the relationship between initial conditions and anisotropic flow, highlighting the significance of nonlinear terms for accurate predictions.

Findings

Initial eccentricity strongly influences anisotropic flow.

Nonlinear terms are crucial for predicting quadrangular flow.

Results aid in constraining hydrodynamic initial conditions from experimental data.

Abstract

In hydrodynamics, the momentum distribution of particles at the end of the evolution is completely determined by initial conditions. We study quantitatively to what extent anisotropic flow is determined by predictors such as the initial eccentricity in a set of realistic simulations, and we also show the importance of nonlinear terms in order to correctly predict the quadrangular flow. This knowledge will be important for making a more direct link between experimental observables and hydrodynamic initial conditions, the latter being poorly constrained at present.