Approaching low-energy QCD with a gauged, nonlocal, constituent-quark model

1992 ◽  
Vol 45 (7) ◽  
pp. 2534-2541 ◽  
Author(s):  
B. Holdom
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Low Energy

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.

The constituent-quark model — Nowadays

2015 ◽  
Vol 30 (02) ◽  
pp. 1530013 ◽  
Author(s):  
W. Plessas
Keyword(s):  
Quantum Chromodynamics ◽  
Quark Model ◽  
Constituent Quark ◽  
Goldstone Boson ◽  
Form Factors ◽  
Constituent Quark Model ◽  
Low Energy ◽  
Universal Model ◽  
Boson Exchange ◽  
Good Agreement

The present performance of the constituent-quark model as an effective tool to describe low-energy hadrons on the basis of quantum chromodynamics is exemplified along the relativistic constituent-quark model with quark dynamics relying on a realistic confinement and a Goldstone-boson-exchange hyperfine interaction. In particular, the spectroscopy of all known baryons is covered within a universal model in good agreement with phenomenology. The structure of the nucleons as probed under electromagnetic, weak, and gravitational interactions is produced in a correct manner. Likewise, the electroweak form factors of the baryons with u, d, and s flavor contents, calculated so far, result reasonably. Shortcomings still remain with regard to hadronic resonance decays.

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.

scholarly journals An overview of the hypercentral constituent quark model

2003 ◽  
Vol 50 (2) ◽  
pp. 263-272 ◽  
Author(s):  
M.M Giannini ◽  
E Santopinto ◽  
A Vassallo
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model

scholarly journals Electromagnetic form factors and the hypercentral constituent quark model

2007 ◽  
Vol 76 (6) ◽  
Author(s):  
M. De Sanctis ◽  
M. M. Giannini ◽  
E. Santopinto ◽  
A. Vassallo
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Form Factors ◽  
Constituent Quark Model ◽  
Electromagnetic Form Factors

scholarly journals STRUCTURE OF LIGHT AND HEAVY PENTAQUARKS

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1797-1802 ◽  
Author(s):  
FL. STANCU
Keyword(s):  
Variational Method ◽  
Hyperfine Interaction ◽  
Quark Model ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Positive Parity ◽  
Model Based ◽  
Quantum Numbers ◽  
The Masses

Light and heavy pentaquarks are described within a constituent quark model based on a spin-flavor hyperfine interaction. In this model the lowest state acquires positive parity. The masses of the light antidecuplet members are calculated dynamically using a variational method. It is shown that the octet and antidecuplet states with the same quantum numbers mix ideally due to SU (3)F breaking. Masses of the charmed antisextet pentaquarks are predicted within the same model.

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