Study of hot and dense nuclear matter in effective QCD model

TL;DR

This thesis investigates hot and dense nuclear matter using effective QCD models, analyzing spectral functions, dilepton rates, and fluctuations to understand properties of quark-gluon plasma in heavy ion collisions.

Contribution

It introduces the application of entangled PNJL models to study spectral functions and dilepton production, highlighting the effects of strong entanglement on these observables.

Findings

Dilepton rate is enhanced in strongly interacting QGP compared to weakly coupled QGP.

Entanglement in PNJL models affects the spectral functions and dilepton production rates.

Inclusion of vector interactions influences conserved density fluctuations and QNS behavior.

Abstract

In this thesis we use various effective QCD models to investigate hot and dense nuclear matter created in heavy ion collisions. To characterize such matter, we mainly exploit correlation functions and some of the associated spectral properties. We explore the vector meson current-current correlation function with and without the influence of vector interaction in Nambu\textendash Jona-Lasinio (NJL) model and also in its Polyakov loop extended version (PNJL). As a spectral property we have computed the dilepton rate which is found to be enhanced in strongly interacting QGP (sQGP) as compared to the Born rate in a weakly coupled QGP. We further consider the idea of entanglement between the chiral and confinement dynamics through the entangled PNJL (EPNJL) model and re-explore the vector spectral function and the spectral property such as the dilepton production rate studied in our earlier effort. Because of the strong entanglement, the coupling strengths run with the temperature and chemical potential. The implications of such running on the dilepton rate have been discussed in details. The Euclidean vector correlator and the response of the conserved density fluctuations related with the temporal vector correlator have also been investigated. We have considered both the scenarios, i.e. presence and absence of the vector interaction. The inclusion of the vector interaction also brings forth some intriguing issues in the fluctuation of conserved density, namely the QNS. It has been discussed in details and we try to address it using EPNJL model. We also assume the QGP to be made of a non-interacting quarks, antiquarks and gluons and construct a partition function which is restricted by the assumption of a color singlet projection to conform with the $SU(3)_c$ symmetry. This type of simple quantum statistical description exhibits very interesting features, which we have discussed in details.