Collision Energy Evolution of Elliptic and Triangular Flow in a Hybrid Model

TL;DR

This paper investigates how elliptic and triangular flow in heavy ion collisions evolve with collision energy using a hybrid model, shedding light on the transition from hadronic matter to quark-gluon plasma.

Contribution

It introduces a hybrid Boltzmann+hydrodynamics model to analyze the energy dependence of flow observables, highlighting the roles of hydrodynamics and hadron transport.

Findings

Collision energy affects initial eccentricities and flow observables.

Hydrodynamics dominates at higher energies, while hadron transport is more important at lower energies.

Results help map the QGP formation threshold.

Abstract

While the existence of a strongly interacting state of matter, known as 'quark-gluon plasma' (QGP), has been established in heavy ion collision experiments in the past decade, the task remains to map out the transition from the hadronic matter to the QGP. This is done by measuring the dependence of key observables (such as particle suppression and elliptic flow) on the collision energy of the heavy ions. This procedure, known as 'beam energy scan', has been most recently performed at the Relativistic Heavy Ion Collider (RHIC). Utilizing a Boltzmann+hydrodynamics hybrid model, we study the collision energy dependence of initial state eccentricities and the final state elliptic and triangular flow. This approach is well suited to investigate the relative importance of hydrodynamics and hadron transport at different collision energies.