scholarly journals Using the Linear Sigma Model with quarks to describe the QCD phase diagram and to locate the critical end point

2018 ◽  
Vol 172 ◽  
pp. 08002
Author(s):  
Alejandro Ayala ◽  
Jorge David Castaño-Yepes ◽  
José Antonio Flores ◽  
Saúl Hernández ◽  
Luis Hernández
Keyword(s):  
Phase Diagram ◽  
Critical Temperature ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Transition Line ◽  
Baryon Chemical Potential ◽  
First Order ◽  
Qcd Phase Diagram ◽  
Crossover Transition

We study the QCD phase diagram using the linear sigma model coupled to quarks. We compute the effective potential at finite temperature and quark chemical potential up to ring diagrams contribution. We show that, provided the values for the pseudo-critical temperature Tc = 155 MeV and critical baryon chemical potential μBc ≃ 1 GeV, together with the vacuum sigma and pion masses. The model couplings can be fixed and that these in turn help to locate the region where the crossover transition line becomes first order.

scholarly journals QCD phase diagram from chiral symmetry restoration: analytic approach at high and low temperature using the Linear Sigma Model with Quarks

2018 ◽  
Vol 64 (3) ◽  
pp. 302 ◽  
Author(s):  
Luis Hernandez ◽  
Alejandro Ayala ◽  
Saul Hernandez-Ortiz
Keyword(s):  
Phase Diagram ◽  
Chiral Symmetry ◽  
Low Temperatures ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Transition Line ◽  
Chiral Symmetry Restoration ◽  
Qcd Phase Diagram ◽  
End Point

We use the linear sigma model with quarks to study the QCD phase diagram from the point of view of chiral symmetry restoration. We compute the leading order effective potential for high and low temperatures and finite quark chemical potential, up to the contribution of the ring diagrams to account for the plasma screening effects. We fix the values of the model couplings using physical values for the input parameters such as  the vacuum pion and sigma masses, the critical temperature at vanishing quark chemical potential and the conjectured end point value of the baryon chemical potential of the transition line at vanishing temperature. We find that the critical end point (CEP) is located at low temperatures and high quark chemical potentials $(\mu^{\text{CEP}}>320\ {\mbox{MeV}},T^{\text{CEP}}<40\ {\mbox{MeV}})$.

scholarly journals SU(3) Polyakov linear-sigma model with finite isospin asymmetry: QCD phase diagram

2019 ◽  
Vol 34 (31) ◽  
pp. 1950199 ◽  
Author(s):  
Abdel Nasser Tawfik ◽  
Abdel Magied Diab ◽  
M. T. Ghoneim ◽  
H. Anwer
Keyword(s):  
Phase Structure ◽  
Sigma Model ◽  
Chemical Potential ◽  
Mean Field ◽  
Field Approximation ◽  
Linear Sigma Model ◽  
Dense Medium ◽  
Mean Field Approximation ◽  
Isospin Asymmetry ◽  
Qcd Phase Diagram

The SU(3) Polyakov linear-sigma model (PLSM) in mean-field approximation is utilized in analyzing the chiral condensates [Formula: see text], [Formula: see text], [Formula: see text] and the deconfinement order parameters [Formula: see text], [Formula: see text], at finite isospin asymmetry. The bulk thermodynamics including pressure density, interaction measure, susceptibility and second-order correlations with baryon, strange and electric charge quantum numbers are studied in thermal and dense medium. The PLSM results are confronted to the available lattice quantum chromodynamics (QCD) calculations. The excellent agreement obtained strengthens the reliability of fixing the PLSM parameters and therefore supports further predictions even beyond the scope of the lattice QCD numerical applicability. From the QCD phase structure at finite isospin chemical potential [Formula: see text], we find that the pseudocritical temperatures decrease with the increase in [Formula: see text]. We conclude that the QCD phase structure in [Formula: see text] plane seems to extend the one in [Formula: see text] plane.

PHASE TRANSITION PATTERNS OF NUCLEAR MATTER BASED ON EXTENDED LINEAR SIGMA MODEL

2013 ◽  
Vol 22 (11) ◽  
pp. 1350077 ◽  
Author(s):  
TRAN HUU PHAT ◽  
NGUYEN TUAN ANH ◽  
PHUNG THI THU HA
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Nuclear Matter ◽  
Degrees Of Freedom ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Baryon Chemical Potential ◽  
Chiral Phase ◽  
The Relationship

We study systematically various types of phase transitions in nuclear matter at finite temperature T and baryon chemical potential μ based on the extended linear sigma model with nucleon degrees of freedom. It is shown that there are three types of phase transitions in nuclear matter: the chiral symmetry nonrestoration (SNR) at high temperature, the well-known liquid–gas (LG) phase transition at sub-saturation density and the Lifshitz phase transition (LPT) from the fully-gapped state to the state with Fermi surface. Their phase diagrams are established in the (T, μ)-plane and their physical properties are investigated in detail. The relationship between the chiral phase transition and the LG phase transition in nuclear matter is discussed.

scholarly journals Crossover-model approach to QCD phase diagram, equation of state and susceptibilities in the 2+1 and 2+1+1 flavor systems

2017 ◽  
Vol 32 (36) ◽  
pp. 1750205 ◽  
Author(s):  
Akihisa Miyahara ◽  
Masahiro Ishii ◽  
Hiroaki Kouno ◽  
Masanobu Yahiro
Keyword(s):  
Phase Diagram ◽  
Equation Of State ◽  
Baryon Number ◽  
Entropy Density ◽  
Transition Line ◽  
Qcd Phase Diagram ◽  
Chemical Potentials ◽  
Number Formula ◽  
Crossover Transition ◽  
Production Probability

We construct a simple model for describing the hadron–quark crossover transition by using lattice QCD (LQCD) data in the [Formula: see text] flavor system, and draw the phase diagram in the [Formula: see text] and [Formula: see text] flavor systems through analyses of the equation of state (EoS) and the susceptibilities. In the present hadron–quark crossover (HQC) model, the entropy density [Formula: see text] is defined by [Formula: see text] with the hadron-production probability [Formula: see text], where [Formula: see text] is calculated by the hadron resonance gas model that is valid in low temperature [Formula: see text] and [Formula: see text] is evaluated by the independent quark model that explains LQCD data on the EoS in the region [Formula: see text] for the [Formula: see text] flavor system and [Formula: see text] for the [Formula: see text] flavor system. The [Formula: see text] is determined from LQCD data on [Formula: see text] and susceptibilities for the baryon-number [Formula: see text], the isospin [Formula: see text] and the hypercharge [Formula: see text] in the [Formula: see text] flavor system. The HQC model is successful in reproducing LQCD data on the EoS and the flavor susceptibilities [Formula: see text] for [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] in the [Formula: see text] flavor system, without changing the [Formula: see text]. We define the hadron–quark transition temperature with [Formula: see text]. For the [Formula: see text] flavor system, the transition line thus obtained is almost identical in [Formula: see text], [Formula: see text], [Formula: see text] planes, when the chemical potentials [Formula: see text] [Formula: see text] are smaller than 250 MeV. This [Formula: see text] approximate equivalence is also seen in the [Formula: see text] flavor system. We plot the phase diagram also in [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] planes in order to investigate flavor dependence of transition lines. In the [Formula: see text] flavor system, [Formula: see text] quark does not affect the [Formula: see text] flavor subsystem composed of [Formula: see text], [Formula: see text], [Formula: see text]. Temperature dependence of the off-diagonal susceptibilities and the [Formula: see text] show that the transition region at [Formula: see text] is [Formula: see text] for both the [Formula: see text] and [Formula: see text] flavor systems.

scholarly journals Chiral Phase Transition in Linear Sigma Model with Nonextensive Statistical Mechanics

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Ke-Ming Shen ◽  
Hui Zhang ◽  
De-Fu Hou ◽  
Ben-Wei Zhang ◽  
En-Ke Wang
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Statistical Mechanics ◽  
Sigma Model ◽  
Chemical Potential ◽  
Linear Sigma Model ◽  
Nonextensive Statistical Mechanics ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Lower Temperature

From the nonextensive statistical mechanics, we investigate the chiral phase transition at finite temperature T and baryon chemical potential μB in the framework of the linear sigma model. The corresponding nonextensive distribution, based on Tsallis’ statistics, is characterized by a dimensionless nonextensive parameter, q, and the results in the usual Boltzmann-Gibbs case are recovered when q→1. The thermodynamics of the linear sigma model and its corresponding phase diagram are analysed. At high temperature region, the critical temperature Tc is shown to decrease with increasing q from the phase diagram in the (T,μ) plane. However, larger values of q cause the rise of Tc at low temperature but high chemical potential. Moreover, it is found that μ different from zero corresponds to a first-order phase transition while μ=0 to a crossover one. The critical endpoint (CEP) carries higher chemical potential but lower temperature with q increasing due to the nonextensive effects.

scholarly journals Locating the QCD Critical Point Using Holographic Black Holes

Proceedings ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 40
Author(s):  
Israel Portillo
Keyword(s):  
Black Holes ◽  
Critical Point ◽  
Chemical Potential ◽  
Transition Line ◽  
Qcd Critical Point ◽  
First Order ◽  
Qcd Phase Diagram ◽  
Baryonic Chemical Potential ◽  
First Order Phase Transition ◽  
First Order Phase

It has been shown that holographic black holes, constructed to mimic the equation of state of QCD computed on the lattice at finite temperature and zero density, display critical behavior at large baryonic chemical potential. In this proceedings, we discuss the mapping of holographic black holes into the QCD phase diagram and the emergence of the critical point and the first order phase transition line.

scholarly journals Relative scale setting for two-color QCD with Nf = 2 Wilson fermions

2020 ◽  
Author(s):  
Kei Iida ◽  
Etsuko Itou ◽  
Tong-Gyu Lee
Keyword(s):  
Phase Diagram ◽  
Critical Temperature ◽  
Pseudoscalar Meson ◽  
Continuum Limit ◽  
Chemical Potential ◽  
Gradient Flow ◽  
Meson Mass ◽  
Qcd Phase Diagram ◽  
Theoretical Analyses ◽  
The Continuum

Abstract We determine the scale setting function and the pseudo-critical temperature on the lattice in Nf = 2 two-color QCD using the Iwasaki gauge and Wilson fermion actions. Although two-color QCD does not correspond to the real world, it is very useful as a good testing ground for three-color QCD. The scale setting function gives the relative lattice spacings of simulations performed at different values of the bare coupling. It is a necessary tool for taking the continuum limit. Firstly, we measure the meson spectra for various combinations of (β, κ) and find a line of constant physics in β – κ plane. Next, we determine the scale setting function via w0 scale in the gradient flow method. Furthermore, we estimate the pseudo-critical temperature at zero chemical potential from the chiral susceptibility.Combining these results, we can discuss the QCD phase diagram in which both axes are given by dimensionless quantities, namely, the temperature normalized by the pseudo-critical temperature on the lattice and the chemical potential normalized by the pseudoscalar meson mass. It makes it easy to compare among several lattice studies and also makes it possible to compare theoretical analyses and lattice studies in the continuum limit.

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