scholarly journals Historical Introduction to Chiral Quark Models

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 252
Author(s):  
Francisco Fernández ◽  
Jorge Segovia
Keyword(s):  
Quark Model ◽  
Chiral Symmetry ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Constituent Quark Model ◽  
Special Issue ◽  
Bag Model ◽  
Breaking Mechanism ◽  
Dynamical Breaking ◽  
Quark Models

Chiral symmetry, and its dynamical breaking, has become a cornerstone in the description of the hadron’s phenomenology at low energy. The present manuscript gives a historical survey on how the quark model of hadrons has been implemented along the last decades trying to incorporate, among other important non-perturbative features of quantum chromodynamics (QCD), the dynamical chiral symmetry breaking mechanism. This effort has delivered different models such as the chiral bag model, the cloudy bag model, the chiral quark model or the chiral constituent quark model. Our main aim herein is to provide a brief introduction of the Special Issue “Advances in Chiral Quark Models” in Symmetry and contribute to the clarification of the differences among the above-mentioned models that include the adjective chiral in their nomenclature.

NONPERTURBATIVE QCD, THE CONSTITUENT QUARK MODEL AND CONFINEMENT

1988 ◽  
Vol 03 (01) ◽  
pp. 203-223 ◽  
Author(s):  
B.H.J. MCKELLAR ◽  
M.D. SCADRON ◽  
R.C. WARNER
Keyword(s):  
Quark Model ◽  
Chiral Symmetry ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Constituent Quark Model ◽  
The Other ◽  
Hadron Structure ◽  
Potential Models ◽  
Dynamical Breaking ◽  
Quark Models

There are currently two major QCD-inspired quark models for hadrons. Nonrelativistic potential models and ultrarelativistic bag models have both had their successes. In this paper we present the case for an alternative quark picture, emphasizing the nonperturbative dynamical breaking of chiral symmetry in QCD. The relativistic constituent quark model which emerges recovers the main results of the other approaches, and also holds better prospects for the calculation of relativistic phenomena, and for the eventual understanding of the interrelations between chiral-symmetry breaking, hadron structure and confinement.

EFFECTIVE DEGREES OF FREEDOM IN LOW-ENERGY QUANTUM CHROMODYNAMICS

2013 ◽  
Vol 28 (26) ◽  
pp. 1360022 ◽  
Author(s):  
WILLIBALD PLESSAS
Keyword(s):  
Quantum Mechanics ◽  
Quantum Chromodynamics ◽  
Quark Model ◽  
Chiral Symmetry ◽  
Degrees Of Freedom ◽  
Constituent Quark ◽  
Mass Operator ◽  
Constituent Quark Model ◽  
Low Energy ◽  
Energy Quantum

Confinement and spontaneous breaking of chiral symmetry are assumed to generate the governing degrees of freedom of low-energy quantum chromodynamics. On this basis a relativistic constituent-quark model is constructed and formulated along an invariant mass operator within Poincaré-invariant quantum mechanics. The model is effectively applied to the spectroscopy of all known baryons of flavors u, d, s, c and b. The mass-operator eigenstates are furthermore tested with regard to the baryon electromagnetic and axial form factors. Through using the point form of relativistic quantum mechanics, these observables are obtained in a manifestly covariant manner. For all light and strange baryon ground states the electroweak structures are reproduced either in good agreement with phenomenology or, if no experimental data exist, in consistency with results available from lattice quantum chromodynamics. It is concluded that the relativistic constituent-quark model, relying on {QQQ} Fock states only, provides a universal framework for the description of low-energy baryons. The most important ingredients are spontaneous chiral-symmetry breaking and strict relativistic invariance.

scholarly journals RESUMMATION STUDY ON VECTOR MESON DECAYS AND CHIRAL SYMMETRY SPONTANEOUSLY BREAKING IN CHIRAL CONSTITUENT QUARK MODEL

2004 ◽  
Vol 19 (01) ◽  
pp. 81-114
Author(s):  
YI-BIN HUANG ◽  
MU-LIN YAN ◽  
XIAO-JUN WANG
Keyword(s):  
Vector Meson ◽  
Quark Model ◽  
Chiral Symmetry ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Energy Scale ◽  
Meson Theory ◽  
Upper Limit ◽  
Light Vector ◽  
Proper Vertex

We study on-shell decays of light vector meson resonances ρ, K* and ϕ in the framework of chiral constituent quark model using resummation calculations. Such studies are necessary for showing that dynamics described by chiral Lagrangian works well at this energy scale. The effective action is derived by a proper vertex method, where resummation of all orders of momentum expansion is accomplished. Also studied are the loop effects of pseudoscalar meson, which play an important role at this energy scale. The numerical results agree well with the experimental data. A new method to explore the chiral symmetry spontaneously breaking (CSSB) is proposed. It is found that the unitarity of the effective meson theory resulted from resummation derivations demands an upper-limit to the momentum of vector meson. This upper-limit, being critical point, is just the energy scale of CSSB, and is found to be flavor-dependent.

scholarly journals WHICH CONSTITUENT QUARK MODEL IS BETTER?

2003 ◽  
Vol 18 (02n06) ◽  
pp. 356-361 ◽  
Author(s):  
FAN WANG ◽  
JIA-LUN PING ◽  
HOU-RONG PANG ◽  
T. GOLDMAN
Keyword(s):  
Comparative Study ◽  
Quark Model ◽  
Hybrid Model ◽  
Constituent Quark ◽  
Goldstone Boson ◽  
Constituent Quark Model ◽  
Exchange Model ◽  
Meson Exchange ◽  
Boson Exchange ◽  
Quark Models

A comparative study has heen done by calculating the effective baryon-baryon interactions of the 64 lowest channels consisting of octet and decuplet baryons with three constituent quark models: the extended quark gluon exchange model, the Goldstone boson exchange model and the quark gluon meson exchange hybrid model. We find that these three models give similar results for 44 channels. Further tests of these models are discussed.

PROPERTIES OF $b\bar{b}$ MESONS IN CONSTITUENT QUARK MODELS

2012 ◽  
Vol 27 (08) ◽  
pp. 1250025 ◽  
Author(s):  
SHAONA CHEN ◽  
JIALUN PING
Keyword(s):  
Quark Model ◽  
B Mesons ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Electric Dipole Transition ◽  
Wave Functions ◽  
Two Photon ◽  
Photon Decay ◽  
Color Confinement ◽  
Quark Models

The properties of bottomonia are investigated in detail in the constituent quark model. The wave functions of bottomonia are obtained by solving Dirac equation and Schrödinger equation. The potentials between quark and antiquark include color confinement (linear and quadratic) and one-gluon-exchange. Based on the obtained wave functions, the electromagnetic and two-photon decay, electric dipole transition, and hadronic width of bottomonia are calculated. The calculated results are in a good agreement with the experimental data. The results also show that the nonrelativistic and relativistic version of quark model can all describe the properties of bottomonia.

scholarly journals STRANGENESS AND CHIRAL SYMMETRY BREAKING

2011 ◽  
Vol 26 (04) ◽  
pp. 279-288 ◽  
Author(s):  
HARLEEN DAHIYA ◽  
NEETIKA SHARMA
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Significant Contribution ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Quantitative Description ◽  
Constituent Quark Model ◽  
Matrix Elements ◽  
Qualitative And Quantitative

The implications of chiral symmetry breaking and SU(3) symmetry breaking have been studied in the chiral constituent quark model (χCQM). The role of hidden strangeness component has been investigated for the scalar matrix elements of the nucleon with an emphasis on the meson–nucleon sigma terms. The χCQM is able to give a qualitative and quantitative description of the "quark sea" generation through chiral symmetry breaking. The significant contribution of the strangeness is consistent with the recent available experimental observations.

scholarly journals Low-lying configurations in a non-relativistic constituent quark model

2007 ◽  
Vol 34 (7) ◽  
pp. 1771-1782 ◽  
Author(s):  
W L Wang ◽  
F Huang ◽  
Z Y Zhang ◽  
Y W Yu ◽  
F Liu
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model

THE NLO QCD CALCULATION OF SEA QUARK DISTRIBUTIONS IN THE CORGI APPROACH, BASED ON THE CONSTITUENT QUARK MODEL

2007 ◽  
Vol 22 (24) ◽  
pp. 4519-4535 ◽  
Author(s):  
A. MIRJALILI ◽  
K. KESHAVARZIAN
Keyword(s):  
Quark Model ◽  
Mellin Transform ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Standard Approach ◽  
Unknown Parameters ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
Physical Scale ◽  
Good Agreement

Sea quark distributions in the NLO approximation, based on the phenomenological valon model or constituent quark model are analyzed. We use the parametrized inverse Mellin transform technique to perform a direct fit with available experimental data and obtain the unknown parameters of the distributions. We try to extend the calculation to the NLO approximation for the singlet and nonsinglet cases in DIS phenomena. We do also the same calculation for electron–positron annihilation. The resulting sea distributions are effectively independent of the process used. The approach of complete RG improvement (CORGI) is employed and the results are compared with the standard approach of perturbative QCD in the [Formula: see text] scheme with a physical scale. The comparisons with data are in good agreement. As is expected, the results in the CORGI approach indicate a better agreement to the data than the NLO calculation in the standard approach.

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