Properties of the partonic phase at RHIC within PHSD

TL;DR

This paper investigates the properties of the partonic phase in relativistic heavy-ion collisions at RHIC energies using the PHSD transport approach, which incorporates a quasiparticle model consistent with lattice QCD results.

Contribution

It introduces and applies the PHSD model to analyze the space-time evolution of partonic matter and its transition to hadrons in nucleus-nucleus collisions, highlighting novel dynamical features.

Findings

Partonic interactions influence elliptic flow of hadrons.

Quark-number scaling observed at top RHIC energy.

PHSD reproduces experimental hadronic spectra.

Abstract

The dynamics of partons, hadrons and strings in relativistic nucleus-nucleus collisions is analyzed within the novel Parton-Hadron-String Dynamics (PHSD) transport approach, which is based on a dynamical quasiparticle model for partons (DQPM) matched to reproduce recent lattice-QCD results -- including the partonic equation of state -- in thermodynamic equilibrium. The transition from partonic to hadronic degrees of freedom is described by covariant transition rates for the fusion of quark-antiquark pairs or three quarks (antiquarks), respectively, obeying flavor current-conservation, color neutrality as well as energy-momentum conservation. In order to explore the space-time regions of 'partonic matter' the PHSD approach is applied to nucleus-nucleus collisions from SPS to RHIC energies. Detailed comparisons are presented for hadronic rapidity spectra and transverse mass distributions. The traces of partonic interactions are found in particular in the elliptic flow of hadrons as well as in an approximate quark-number scaling at the top RHIC energy.