Hydrodynamics with a chiral hadronic equation of state including quark degrees of freedom

TL;DR

This paper explores how a deconfinement phase transition affects the dynamics of hot, dense nuclear matter in heavy-ion collisions, using a hybrid model with an equation of state that includes a critical end point and quark degrees of freedom.

Contribution

It introduces a hybrid hydrodynamic model with a chiral hadronic equation of state incorporating a critical end point and quark degrees of freedom, linking deconfinement and chiral restoration.

Findings

Results show observable differences linked to the phase transition.

Comparison with non-interacting hadron resonance gas highlights phase transition effects.

Model aligns with lattice data for the critical end point.

Abstract

We investigate the influence of a deconfinement phase transition on the dynamics of hot and dense nuclear matter. We apply a hybrid model where an intermediate hydrodynamics stage is employed for the the hot and dense stage of a system created in head-on collisions of Pb+Pb/Au+Au at beam energies from $2-160A $GeV. The initial and final interactions are performed by a microscopic transport approach (UrQMD). An equation of state that incorporates a critical end point (CEP) in line with lattice data is used. It follows from coupling the Polyakov loop (as an order parameter for deconfinement) to a chiral hadronic $SU(3)_f$ model. In this configuration the EoS describes chiral restoration as well as the deconfinemt phase transition. We compare the results obtained in this approach to results from a non interacting hadron resonance gas, focussing on observables deemed to be sensitive to the phase transition to the quark gluon plasma.