Thermodynamics and higher order moments in SU(3) linear σ-model with gluonic quasiparticles

Abstract

In framework of linear σ-model (LSM) with three quark flavors, the chiral phase-diagram at finite temperature and density is investigated. At temperatures higher than the critical temperature (T c ), we added to LSM the gluonic sector from the quasi-particle model (QPM), which assumes that the interacting gluons in the strongly interacting matter, the quark-gluon plasma (QGP), are phenomenologically the same as non-interacting massive quasi-particles. The dependence of the chiral condensates of strange and non-strange quarks on temperature and chemical potential is analysed.Then, we have calculated the thermodynamics in the new approach (combination of LSM and QPM).Confronting the results with recent lattice QCD simulations shows an excellent agreement in almost all thermodynamic quantities. The first and second order moments of particle multiplicity are studied in dependence on the chemical potential but at fixed temperature and on the chemical potential but at fixed temperature. These are implemented in characterizing the large fluctuations accompanying the chiral phase-transition. The results of first and second order moments are compared with the SU(3) Polyakov linear σ-model (PLSM). Also, the resulting phase-diagrams deduced in PLSM and LSM+QPM are compared with each other. The interactions between the basic building blocks (quarks, gluons, leptons and force mediators) of the visible matter in the Universe are controlled by fundamental interactions (except gravity). The quantum electrodynamics (QED) gives a very good description for the electromagnetic phenomena. The strong interaction can be described by the quantum chromodynamics (QCD) with an asymptotic freedom [1, 2] meaning that the strong coupling becomes small when the momentum scale for the considered processes becomes large. This leads to a phase transition from hadronic matter, in which quarks and gluons are confined at low temperature and density to a new state-of-mater [3, 4], called quark-gluon plasma (QGP), in which quarks and gluons are no longer confined at high temperature and large density [5]. The theoretical and experimental studies of QGP still represent a challenge to be faced by scientists. So far, there are many heavy-ion experiments aiming to create that phase of matter and to study its properties for example the ones operating with the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC). From theoretical point-of-view, there are -apart from QCD and its numerical simulations -many first-principle models, like perturbative Nambu-Jona-Lasinio (PNJL) model [6-8], Polyakov linear σ-model (PLSM), Polyakov quark meson model (PQM) [9][10][11]. Also the quasi-particle model (QPM) [12][13][14] was suggested to reproduce the lattice QCD calculations. Each of these model has strong and weak features. The compilation between different effective models was suggested [15], for instance, an extension in NJL to include Hadron Resonance Gas (HRG). In the present paper, we implement the same compilation aiming to fully reproduce...

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