Collision-System and Beam-Energy Dependence of Anisotropic Flow Fluctuations

TL;DR

This study investigates how anisotropic flow fluctuations depend on collision system, energy, and centrality in heavy-ion collisions, revealing initial-state fluctuations as the dominant source across various conditions.

Contribution

It provides a comprehensive analysis of flow fluctuations across different collision systems and energies, highlighting the dominance of initial-state effects over other factors.

Findings

Flow fluctuations strongly depend on collision centrality.

Flow fluctuations show modest dependence on system size.

Flow fluctuations are largely independent of particle species and beam energy.

Abstract

Elliptic flow measurements from two-, four- and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at $\sqrt{s_{\rm NN}}$= 193 GeV, Cu+Au at $\sqrt{s_{\rm NN}}$= 200 GeV and Au+Au spanning the range $\sqrt{s_{\rm NN}}$= 11.5 - 200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and T$\mathrel{\protect\raisebox{-2.1pt}{R}}$ENTo model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.