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 Extended Goldstone-boson-exchange constituent-quark model

2005 ◽  
Vol 23 (3) ◽  
pp. 507-515 ◽  
Author(s):  
K. Glantschnig ◽  
R. Kainhofer ◽  
W. Plessas ◽  
B. Sengl ◽  
R. F. Wagenbrunn
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Goldstone Boson ◽  
Constituent Quark Model ◽  
Boson Exchange

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 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.

scholarly journals Extended Goldstone-boson-exchange constituent quark model

2000 ◽  
Vol 663-664 ◽  
pp. 703c-706c ◽  
Author(s):  
R.F. Wagenbrunn ◽  
L.Ya. Glozman ◽  
W. Plessas ◽  
K. Varga
Keyword(s):  
Quark Model ◽  
Constituent Quark ◽  
Goldstone Boson ◽  
Constituent Quark Model ◽  
Boson Exchange

scholarly journals Covariant nucleon electromagnetic form factors from the Goldstone-boson-exchange quark model

2001 ◽  
Vol 511 (1) ◽  
pp. 33-39 ◽  
Author(s):  
R.F. Wagenbrunn ◽  
S. Boffi ◽  
W. Klink ◽  
W. Plessas ◽  
M. Radici
Keyword(s):  
Quark Model ◽  
Goldstone Boson ◽  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Boson Exchange

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 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
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