Flow correlations from a hydrodynamics model with dynamical freeze-out and initial conditions based on perturbative QCD and saturation

TL;DR

This paper enhances a hydrodynamics model for heavy-ion collisions by incorporating dynamical freeze-out and bulk viscosity, improving the description of flow observables across centralities at RHIC and LHC.

Contribution

It introduces dynamical freeze-out conditions and bulk viscosity into the EKRT framework, extending its applicability to peripheral collisions and improving agreement with experimental data.

Findings

Better description of flow coefficients in peripheral collisions

Extended centrality range for constraining QCD matter properties

Improved match with experimental flow correlations

Abstract

We extend the applicability of the hydrodynamics, perturbative QCD and saturation -based EKRT (Eskola-Kajantie-Ruuskanen-Tuominen) framework for ultrarelativistic heavy-ion collisions to peripheral collisions by introducing dynamical freeze-out conditions. As a new ingredient compared to the previous EKRT computations we also introduce a non-zero bulk viscosity. We compute various hadronic observables and flow correlations, including normalized symmetric cumulants, mixed harmonic cumulants and flow-transverse momentum correlations, and compare them against measurements from the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). We demonstrate that the inclusion of the dynamical freeze-out and bulk viscosity allows a better description of the measured flow coefficients in peripheral collisions and enables the use of an extended centrality range when constraining the properties of QCD matter in the future.