Anisotropic flow decorrelation in heavy-ion collisions with event-by-event viscous hydrodynamics

TL;DR

This paper investigates how elliptic flow decorrelation varies with rapidity in heavy-ion collisions using event-by-event viscous hydrodynamics, linking initial state anisotropies and final state effects across different energies and systems.

Contribution

It introduces a hybrid simulation approach combining viscous hydrodynamics and hadronic cascade, showing improved agreement with experimental data and elucidating the role of initial conditions and final state interactions.

Findings

Decorrelation of elliptic flow depends on initial spatial anisotropies.

Final state hadronic cascade amplifies flow decorrelation.

Extended Monte Carlo Glauber model better matches experimental data.

Abstract

Decorrelation of the elliptic flow in rapidity is calculated within a hybrid approach which includes event-by-event viscous fluid dynamics and final state hadronic cascade model. The simulations are performed for Au+Au collisions at center-of-mass collision energies of 27 and 200 GeV per nucleon pair, as well as various colliding systems at 72 GeV per nucleon pair. Initial conditions determined by an extended Monte Carlo Glauber model show better agreement with experimental data than initial conditions from the UrQMD transport model. We show how the observed decorrelation is connected with the decorrelation of initial state spatial anisotropies. We also study how the effect is increased by the final state hadronic cascade.