How much does the hadronic phase contribute to the observed anisotropic flow at the LHC?

TL;DR

This paper investigates the contribution of the hadronic phase to elliptic flow in heavy-ion collisions at the LHC, using experimental data and hydrodynamical models to understand the phase's impact on observed anisotropic flow signals.

Contribution

It provides a detailed comparison of experimental elliptic flow data with hydrodynamical models including and excluding the hadronic phase, to quantify its contribution.

Findings

Energy dependence of elliptic flow explained by a boosted thermal system.

Hadronic re-interactions influence identified particle flow.

Model comparisons constrain hadron-hadron cross-sections.

Abstract

Elliptic flow signals the presence of multiple interactions between the constituents of the created matter in heavy-ion collisions. This includes possible contributions from the different phases, including the hadronic phase. In these proceedings I will first show that the energy dependence of elliptic flow, based on recent ALICE and STAR beam energy scan measurements, can largely be understood in terms of a boosted thermal system. In addition, a detailed comparison between the identified particle elliptic flow measured by the ALICE collaboration and viscous hydrodynamical model calculations with and without a hadronic afterburner is performed to constrain the possible effects of individual hadron-hadron re-interaction cross-sections.