scholarly journals First-order chiral phase transition in high-energy collisions: Can nucleation prevent spinodal decomposition?

2001 ◽  
Vol 63 (11) ◽  
Author(s):  
O. Scavenius ◽  
A. Dumitru ◽  
E. S. Fraga ◽  
J. T. Lenaghan ◽  
A. D. Jackson
Keyword(s):  
Phase Transition ◽  
Spinodal Decomposition ◽  
High Energy ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
First Order ◽  
High Energy Collisions

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.

scholarly journals On the order of the QCD chiral phase transition for different numbers of quark flavours

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Francesca Cuteri ◽  
Owe Philipsen ◽  
Alessandro Sciarra
Keyword(s):  
Phase Transition ◽  
Parameter Space ◽  
Chiral Limit ◽  
Lattice Parameter ◽  
Second Order ◽  
Critical Surface ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
First Order ◽  
The Continuum

Abstract The nature of the QCD chiral phase transition in the limit of vanishing quark masses has remained elusive for a long time, since it cannot be simulated directly on the lattice and is strongly cutoff-dependent. We report on a comprehensive ongoing study using unimproved staggered fermions with Nf ∈ [2, 8] mass-degenerate flavours on Nτ ∈ {4, 6, 8} lattices, in which we locate the chiral critical surface separating regions with first-order transitions from crossover regions in the bare parameter space of the lattice theory. Employing the fact that it terminates in a tricritical line, this surface can be extrapolated to the chiral limit using tricritical scaling with known exponents. Knowing the order of the transitions in the lattice parameter space, conclusions for approaching the continuum chiral limit in the proper order can be drawn. While a narrow first-order region cannot be ruled out, we find initial evidence consistent with a second-order chiral transition in all massless theories with Nf ≤ 6, and possibly up to the onset of the conformal window at 9 ≲ $$ {N}_{\mathrm{f}}^{\ast } $$ N f ∗ ≲ 12. A reanalysis of already published $$ \mathcal{O} $$ O (a)-improved Nf = 3 Wilson data on Nτ ∈ [4, 12] is also consistent with tricritical scaling, and the associated change from first to second-order on the way to the continuum chiral limit. We discuss a modified Columbia plot and a phase diagram for many-flavour QCD that reflect these possible features.

scholarly journals TOPOLOGICAL STRING DEFECT FORMATION DURING THE CHIRAL PHASE TRANSITION

2002 ◽  
Vol 17 (08) ◽  
pp. 1149-1158 ◽  
Author(s):  
A. P. BALACHANDRAN ◽  
S. DIGAL
Keyword(s):  
Phase Transition ◽  
Heavy Ion Collisions ◽  
Transverse Energy ◽  
Defect Formation ◽  
Topological String ◽  
Heavy Ion ◽  
High Energy ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Ion Collisions

We extend and generalize the seminal work of Brandenberger, Huang and Zhang on the formation of strings during chiral phase transitions1 and discuss the formation of Abelian and non-Abelian topological strings during such transitions in the early universe and in the high energy heavy-ion collisions. Chiral symmetry as well as deconfinement are restored in the core of these defects. Formation of a dense network of string defects is likely to play an important role in the dynamics following the chiral phase transition. We speculate that such a network can give rise to non-azimuthal distribution of transverse energy in heavy-ion collisions.

First-order chiral phase transition with a realistic current-quark spectrum

1988 ◽  
Vol 37 (5) ◽  
pp. 1343-1346 ◽  
Author(s):  
R. V. Gavai ◽  
J. Potvin ◽  
S. Sanielevici
Keyword(s):  
Phase Transition ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
First Order ◽  
Current Quark

scholarly journals NONLINEAR SIGMA MODEL APPROACH FOR PHASE DISORDER TRANSITIONS IN CHIRAL GROSS–NEVEU, NAMBU–JONA-LASINIO MODELS AND STRONG-COUPLING SUPERCONDUCTORS

2001 ◽  
Vol 16 (07) ◽  
pp. 1175-1197 ◽  
Author(s):  
EGOR BABAEV
Keyword(s):  
Phase Transition ◽  
Strong Coupling ◽  
Sigma Model ◽  
High Energy ◽  
Bcs Theory ◽  
Nonlinear Sigma Model ◽  
Chiral Phase ◽  
Chiral Phase Transition ◽  
Pseudogap Phase ◽  
Model Approach

We briefly review the nonlinear sigma model approach for the subject of increasing interest: "two-step" phase transitions in the Gross–Neveu and the modified Nambu–Jona-Lasinio models at low N and condensation from pseudogap phase in strong-coupling superconductors. Recent success in describing of "Bose-type" superconductors that possess two characteristic temperatures and a pseudogap above Tc is the development approximately comparable with the BCS theory. One can expect that it should have influence on high-energy physics, similar to impact of the BCS theory on this subject. Although first generalizations of this concept to particle physics were made recently, these results were not systematized. In this review we summarize this development and discuss similarities and differences of the appearance of the pseudogap phase in superconductors and the Gross–Neveu and Nambu–Jona-Lasinio-like models. We discuss its possible relevance for chiral phase transition in QCD and color superconductors. This paper is organized in three parts. In the first part, we briefly review the separation of temperatures of pair formation and pair condensation in strong-coupling and low carrier density superconductors (i.e. the formation of the pseudogap phase). The second part is a review of nonlinear sigma model approach to an analogous phenomenon in the chiral Gross–Neveu model at small N. In the third part we discuss the modified Nambu–Jona-Lasinio model where the chiral phase transition is accompanied by a formation of a phase analogous to the pseudogap phase.

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