scholarly journals Chiral symmetry restoration and the critical end point in QCD

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 1039-1044 ◽  
Author(s):  
Jose Rubén Morones-Ibarra ◽  
Armando Enriquez-Perez-Gavilan ◽  
Abraham Israel Hernández Rodriguez ◽  
Francisco Vicente Flores-Baez ◽  
Nallaly Berenice Mata-Carrizalez ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Chemical Potential ◽  
Quark Condensate ◽  
Number Density ◽  
Chiral Symmetry Restoration ◽  
Chiral Phase ◽  
Quark Number ◽  
Quark Number Susceptibility ◽  
Transition Type

AbstractIn a system of quark matter we study the chiral phase transition, the behavior of the chiral and quark number susceptibility and the CEP at finite temperature and chemical potential. This is done within the framework of two-flavor Nambu and Jona-Lasinio model. We have calculated the chiral quark condensate and the quark number density and, with this, we have found the phase transition type. With these quantities we have determined the phase diagram for QCD and the CEP.

Thermodynamic properties of light mesons and phase transition in an extended SU(2) NJL model

2019 ◽  
Vol 34 (13) ◽  
pp. 1950070
Author(s):  
J. R. Morones Ibarra ◽  
A. J. Garza Aguirre ◽  
Francisco V. Flores-Baez
Keyword(s):  
Chemical Potential ◽  
Pion Mass ◽  
Quark Condensate ◽  
The Other ◽  
Chiral Symmetry Restoration ◽  
Chiral Phase ◽  
Potential Dependence ◽  
Njl Model ◽  
The Masses ◽  
Sigma Meson

In this work, we study the temperature and chemical potential dependence of the masses of sigma and pion mesons as well as the quark condensate by using a SU(2) flavor version of the Nambu–Jona–Lassino model, introducing a prescription that mimics confinement. We have found that as the temperature increases, the mass of sigma shifts down, while the pion mass remains almost constant. On the other hand, the quark condensate decreases as the temperature and chemical potential increases. We have also analyzed the temperature and chemical potential dependence of the spectral function of the sigma meson, from which we observe at low values of T and [Formula: see text] an absence of a peak. Furthermore, as the Mott temperature is reached, its value increases abruptly and a distinct peak emerges, which is related with the dissociation of the sigma. For the case of [Formula: see text], the Mott dissociation is exhibited about the temperature of 189 MeV. We have also obtained the chiral phase diagram and the meson dissociation for different values of [Formula: see text]. From these results, we can state a relation between chiral symmetry restoration and Mott dissociation.

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.

QCD susceptibilities in the presence of the chiral chemical potential

2020 ◽  
Vol 35 (16) ◽  
pp. 2050137
Author(s):  
Run-Lin Liu ◽  
Hong-Shi Zong
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Chemical Potential ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Chiral Phase ◽  
First Order Phase Transition ◽  
Phase Transition Region ◽  
First Order Phase

In this paper, chiral chemical potential [Formula: see text] is introduced to investigate the QCD susceptibilities and chiral phase transition within the Polyakov-loop-extended Nambu–Jona-Lasinio models in the mean-field approximation. We concentrate on the effect of chiral chemical potential on the phase diagram and the QCD susceptibilities. Moreover, it is worth noting that chiral chemical potential has more and more prominent impact on the susceptibilities and the phase diagram with the decrease of temperature based on our results, which coincides with the prediction that the chiral symmetry is dynamically broken in the first-order phase transition region and gets partly restored in the crossover region.

scholarly journals Analytic study on chiral phase transition in holographic QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Meng-Wei Li ◽  
Yi Yang ◽  
Pei-Hung Yuan
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Black Hole ◽  
Chemical Potential ◽  
Chiral Symmetry Breaking ◽  
Chiral Phase ◽  
First Order ◽  
Holographic Qcd ◽  
Small Chemical ◽  
Bypass Mechanism

Abstract The chiral symmetry breaking (χsb) is one of the most fundamental problems in QCD. In this paper, we calculate quark condensation analytically in a holographic QCD model dual to the Einstein-Maxwell-Dilaton (EMD) system coupled to a probe scalar field. We find that the black hole phase transition in the EMD system seriously affects χsb. At small chemical potential, χsb behaves as a crossover. For large chemical potential μ > μc, χsb becomes first order with exactly the same transition temperature as the black hole phase transition by a bypass mechanism. The phase diagram we obtained is qualitatively consistent with the recent results from lattice QCD simulations and NJL models.

scholarly journals On SU(3) Effective Models and Chiral Phase Transition

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Abdel Nasser Tawfik ◽  
Niseem Magdy
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Lattice Qcd ◽  
High Energy ◽  
Particle Model ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Thermal Models ◽  
Qcd Phase Diagram ◽  
Freeze Out

Sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL) model and Polyakov linear sigma-model (PLSM) has been utilized in studying QCD phase-diagram. From quasi-particle model (QPM) a gluonic sector is integrated into LSM. The hadron resonance gas (HRG) model is used in calculating the thermal and dense dependence of quark-antiquark condensate. We review these four models with respect to their descriptions for the chiral phase transition. We analyze the chiral order parameter, normalized net-strange condensate, and chiral phase-diagram and compare the results with recent lattice calculations. We find that PLSM chiral boundary is located in upper band of the lattice QCD calculations and agree well with the freeze-out results deduced from various high-energy experiments and thermal models. Also, we find that the chiral temperature calculated from HRG is larger than that from PLSM. This is also larger than the freeze-out temperatures calculated in lattice QCD and deduced from experiments and thermal models. The corresponding temperature and chemical potential are very similar to that of PLSM. Although the results from PNJL and QLSM keep the same behavior, their chiral temperature is higher than that of PLSM and HRG. This might be interpreted due the very heavy quark masses implemented in both models.

Studies on proper time regularization and the QCD chiral phase transition

2019 ◽  
Vol 34 (01) ◽  
pp. 1950003
Author(s):  
Yu-Qiang Cui ◽  
Zhong-Liang Pan
Keyword(s):  
Phase Transition ◽  
Small Parameter ◽  
Effective Mass ◽  
Finite Temperature ◽  
Chemical Potential ◽  
Proper Time ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Njl Model ◽  
The Difference

We investigate the finite-temperature and zero quark chemical potential QCD chiral phase transition of strongly interacting matter within the two-flavor Nambu–Jona-Lasinio (NJL) model as well as the proper time regularization. We use two different regularization processes, as discussed in Refs. 36 and 37, separately, to discuss how the effective mass M varies with the temperature T. Based on the calculation, we find that the M of both regularization schemes decreases when T increases. However, for three different parameter sets, quite different behaviors will show up. The results obtained by the method in Ref. 36 are very close to each other, but those in Ref. 37 are getting farther and farther from each other. This means that although the method in Ref. 37 seems physically more reasonable, it loses the advantage in Ref. 36 of a small parameter dependence. In addition, we also, find that two regularization schemes provide similar results when T [Formula: see text] 100 MeV, while when T is larger than 100 MeV, the difference becomes obvious: the M calculated by the method in Ref. 36 decreases more rapidly than that in Ref. 37.

A MODEL STUDY OF QUARK NUMBER SUSCEPTIBILITY AT FINITE CHEMICAL POTENTIAL AND ZERO TEMPERATURE

2009 ◽  
Vol 24 (12) ◽  
pp. 2241-2251 ◽  
Author(s):  
YAN-BIN ZHANG ◽  
FENG-YAO HOU ◽  
YU JIANG ◽  
WEI-MIN SUN ◽  
HONG-SHI ZONG
Keyword(s):  
General Result ◽  
Chemical Potential ◽  
Direct Method ◽  
Quark Propagator ◽  
Zero Temperature ◽  
Quark Number ◽  
Model Study ◽  
Analytic Expression ◽  
A Direct Method ◽  
Quark Number Susceptibility

In this paper, we try to provide a direct method for calculating quark number susceptibility at finite chemical potential and zero temperature. In our approach, quark number susceptibility is totally determined by G[μ](p) (the dressed quark propagator at finite chemical potential μ). By applying the general result given in Phys. Rev. C71, 015205 (2005), G[μ](p) is calculated from the model quark propagator proposed in Phys. Rev. D67, 054019 (2003). From this the full analytic expression of quark number susceptibility at finite μ and zero T is obtained.

Quark-Number Susceptibility at Finite Chemical Potential and Zero Temperature

2008 ◽  
Vol 25 (2) ◽  
pp. 440-443 ◽  
Author(s):  
He Deng-Ke ◽  
Jiang Yu ◽  
Feng Hong-Tao ◽  
Sun Wei-Min ◽  
Zong Hong-Shi
Keyword(s):  
Chemical Potential ◽  
Zero Temperature ◽  
Quark Number ◽  
Quark Number Susceptibility
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