CHIRAL SYMMETRY BREAKING AND FORMULAS OF QUARK CONVERSION FOR LOW-ENERGY HADRONIC MATRIX ELEMENTS

1993 ◽  
Vol 08 (05) ◽  
pp. 853-872 ◽  
Author(s):  
ANDREI N. IVANOV
Keyword(s):  
Chiral Symmetry ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Low Energy ◽  
Collective Excitations ◽  
Spontaneous Breaking ◽  
Matrix Elements ◽  
Energy Approximation ◽  
Meson States ◽  
Current Quark

By using the extended Nambu-Jona-Lasinio model for the low-energy approximation of QCD we derive the formulas, being due to spontaneous breaking of chiral symmetry and bosonization, and allowing to express matrix elements of any operator with current-quark fields in the definition in terms of matrix elements of this operator determined via constituent-quark fields interacting with low-lying meson states appearing as [Formula: see text]-collective excitations, which have the self-interactions too.

CHIRAL SYMMETRY BREAKING AND THE GLUON CONDENSATE

1993 ◽  
Vol 08 (04) ◽  
pp. 335-339
Author(s):  
M. FABER ◽  
A.N. IVANOV ◽  
M. NAGY ◽  
N.I. TROITSKAYA
Keyword(s):  
Magnetic Field ◽  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Sum Rules ◽  
Chiral Symmetry Breaking ◽  
Gluon Condensate ◽  
Quark Condensate ◽  
Low Energy ◽  
Qcd Sum Rules ◽  
Energy Approximation

For the low-energy approximation of QCD, the extended Nambu-Jona-Lasinio model has been used. Quarks interact with an external homogeneous color-magnetic field, simulating the contribution of the gluon condensate. The value of the gluon condensate, needed to reach the correct value of the quark condensate, is determined and agrees well with the value obtained from QCD sum rules.

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.

VACUUM STRUCTURE, CHIRAL SYMMETRY BREAKING AND STATIC PROPERTIES OF OCTET AND DECUPLET BARYONS

1996 ◽  
Vol 05 (04) ◽  
pp. 649-667
Author(s):  
A.R. PANDA ◽  
K.C. ROY ◽  
R.K. SAHOO
Keyword(s):  
Chiral Symmetry ◽  
Reasonable Agreement ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Wave Functions ◽  
Static Properties ◽  
Vacuum Structure ◽  
Model Yield ◽  
Quark Field ◽  
Quark Wave Function

The static properties of the octet and decuplet baryons are considered within the framework of a quark model of hadrons where the chiral symmetry is broken dynamically through a nontrivial vacuum structure. The pion and kaon being treated consistently within the model yield to the constituent quark wave function approximately same as the wave functions from the gap equations and thus determine consequently the constituent quark field operators. The model was successfully used earlier to study some hadronic phenomena and here also it estimates the static properties of the octet and decuplet baryons in a unified manner, in reasonable agreement with the available measurements. The only parameter of the model is the harmonic oscillator radius for the baryons. The method is nonperturbative with respect to the equal time algebra for the constituent quark field operators.

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.

scholarly journals Chiral symmetry breaking by monopole condensation

2017 ◽  
Vol 32 (23n24) ◽  
pp. 1750139 ◽  
Author(s):  
Aiichi Iwazaki
Keyword(s):  
Symmetry Breaking ◽  
Pair Production ◽  
Chiral Symmetry ◽  
Chiral Symmetry Breaking ◽  
Chiral Condensate ◽  
Low Energy ◽  
Chiral Anomaly ◽  
Symmetric Pair ◽  
Color Charge ◽  
Massless Quark

Under the assumption of Abelian dominance in QCD, we have shown that chiral condensate is locally present around each QCD monopole. The essence is that either charge or chirality of a quark is not conserved, when the low energy massless quark collides with QCD monopole. In reality, the charge is conserved so that the chirality is not conserved. Reviewing the presence of the local chiral condensate, we show by using chiral anomaly that chiral nonsymmetric quark pair production takes place when a color charge is putted in a vacuum with monopole condensation, while chiral symmetric pair production takes place in a vacuum with no monopole condensation. Our results strongly indicate that the chiral symmetry is broken by the monopole condensation.

Vacuum Structure, Chiral Symmetry Breaking and Radiative Decays of Vector Mesons

1997 ◽  
Vol 06 (01) ◽  
pp. 121-134
Author(s):  
A. R. Panda ◽  
K. C. Roy
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Radiative Decay ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Vector Mesons ◽  
Model Calculations ◽  
Vacuum Structure ◽  
Quark Field ◽  
Decay Widths

The radiative decay widths of vector mesons were considered in a model involving chiral symmetry breaking through a nontrivial vacuum structure where the pion and kaon being treating consistently yield the constituent quark wave functions, approximately the same as that obtained from the gap equations and thus in a way determine the constituent quark field operators. Like its earlier success to some low energy hadronic phenomena, here also the model calculations of radiative decay widths of mesons are in reasonable agreements with other theoretical estimations as well as experimental measurements.

DIMENSIONAL DEPENDENCE OF CHIRAL-SYMMETRY- BREAKING PHASE TRANSITION IN QUENCHED PLANAR QED

1989 ◽  
Vol 04 (22) ◽  
pp. 2155-2166 ◽  
Author(s):  
KEI-ICHI KONDO ◽  
HAJIME NAKATANI
Keyword(s):  
Phase Transition ◽  
Chiral Symmetry ◽  
Chiral Symmetry Breaking ◽  
Scaling Law ◽  
Mean Field ◽  
Dyson Equation ◽  
Essential Singularity ◽  
Spontaneous Breaking ◽  
Planar Approximation ◽  
Singularity Type

We consider the critical behavior of the phase transition associated with the spontaneous breaking of chiral-symmetry in (QED) D, in the framework of the Schwinger-Dyson equation. Special attention is paid on the scaling law. While it is well known that quenched planar QED 4 obeys the Miransky scaling of the essential singularity type, our numerical calculations show that QED 5 and QED 6 do obey the mean-field type scaling, even in the quenched planar approximation. Thus the essential singularity type scaling in the cutoff QED is considered to be possible only when D=4 under the quenched planar approximation.

scholarly journals The Dual QCD @ Work: 2018

2018 ◽  
Vol 192 ◽  
pp. 00048
Author(s):  
Andrzej J. Buras
Keyword(s):  
Lattice Qcd ◽  
New Physics ◽  
Low Energy ◽  
Effective Theory ◽  
Matrix Elements ◽  
General Study ◽  
The Road ◽  
The Past ◽  
Recent Developments ◽  
Energy Approximation

The Dual QCD (DQCD) framework, based on the ideas of ’t Hooft and Witten, and developed by Bill Bardeen, Jean-Marc Gérard and myself in the 1980s is not QCD, a theory of quarks and gluons, but a successful low energy approximation of it when applied to K → ππ decays and K¯0 - K0 mixing. After years of silence, starting with 2014, this framework has been further developed in order to improve the SM prediction for the ratio ε'/ε, the ΔI = 1/2 rule and B^K. Most importantly, this year it has been used for the calculation of all K → ππ hadronic matrix elements of BSM operators which opened the road for the general study of ε'/ε in the context of the SM effective theory (SMEFT). This talk summarizes briefly the past successes of this framework and discusses recent developments which lead to a master formula for ε'/ε valid in any extension of the SM. This formula should facilitate the search for new physics responsible for the ε'/ε anomaly hinted by 2015 results from lattice QCD and DQCD.

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.

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