Hadron-quark phase transition in a hadronic and Polyakov--Nambu--Jona-Lasinio models perspective

TL;DR

This paper investigates the hadron-quark phase transition by matching relativistic hadrodynamical models with Polyakov-Nambu-Jona-Lasinio models, revealing the influence of nuclear forces and comparing with MIT bag model results.

Contribution

It introduces a systematic comparison of hadron-quark phase transition models using RMF-PNJL and RMF-MIT approaches, highlighting the importance of nuclear degrees of freedom.

Findings

RMF-PNJL predicts larger hadronic phases than pure Polyakov quark models.

RMF-MIT shows larger hadron regions but smaller mixed phases compared to RMF-PNJL.

Nuclear forces significantly affect the resistance of hadronic matter to compression.

Abstract

In this work we study the hadron-quark phase transition matching relativistic hadrodynamical mean-field models (in the hadronic phase) with the more updated versions of the Polyakov-Nambu-Jona-Lasinio models (on the quark side). Systematic comparisons are performed showing that the predicted hadronic phases of the matching named as RMF-PNJL, are larger than the confined phase obtained exclusively by the Polyakov quark models. This important result is due to the effect of the nuclear force that causes more resistance of hadronic matter to isothermal compressions. For sake of comparison, we also obtain the matchings of the hadronic models with the MIT bag model, named as RMF-MIT, showing that it presents always larger hadron regions, while shows smaller mixed phases than that obtained from the RMF-PNJL ones. Thus, studies of the confinement transition in nuclear matter, done only with quark models, still need nuclear degrees of freedom to be more reliable in the whole $T\times\mu$ phase diagram.