The colour of quarks (original) (raw)
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Physics Reports, 1997
Starting from the observation that colour charge is only well defined on gauge invariant states, we construct perturbatively gauge invariant, dynamical dressings for individual quarks. Explicit calculations show that an infra-red finite mass-shell renormalisation of the gauge invariant, dressed propagator is possible and, further, that operator product effects, which generate a running mass, may be included in a gauge invariant way in the propagator. We explain how these fields may be combined to form hadrons and show how the interquark potential can now be directly calculated. The onset of confinement is identified with an obstruction to building a non-perturbative dressing. We propose several methods to extract the hadronic scale from the interquark potential. Various extensions are discussed.
The glue around quarks and the interquark potential
Nuclear Physics B - Proceedings Supplements, 1999
The quarks of quark models cannot be identified with the quarks of the QCD Lagrangian. We review the restrictions that gauge field theories place on any description of physical (colour) charges. A method to construct charged particles is presented. The solutions are applied to a variety of applications. Their Green's functions are shown to be free of infra-red divergences to all orders in perturbation theory. The interquark potential is analysed and it is shown that the interaction responsible for anti-screening results from the force between two separately gauge invariant constituent quarks. A fundamental limit on the applicability of quark models is identified.
Quark-Gluon Coupling in the Global Colour Model of QCD
1997
The Global Colour Model of QCD is used in conjunction with a pure-gluon lattice correlator (by Marenzoni et al.) to extract from meson data a momentum-dependent quark-gluon coupling down to sapprox0.3GeV2s \approx 0.3 GeV^2sapprox0.3GeV2. This is compared with a lattice calculation (by Skullerud) of the quark-gluon coupling.
Color" as a classification symmetry and quark charges
Physical Review D, 1976
We discuss the problem of defining a residual global symmetry for classification purposes in the context of a spontaneously broken gauge theory of strong, weak, and electromagnetic interactions, where strong interactions are associated with a local color SU(3)' group. We show that a weakly broken SU(3), [different from but related to SU(3)'] can always be realized as a good classification symmetry for a class of models with integer-charge quarks and massive gluons. For fractionally charged quark models, the symmetry SU(3)c is exact even for massive gluons, only if the full theory contains an Abelian U(1) symmetry associated with electric charge. If there is no such U(1) symmetry in the theory, and we wish to preserve a three-color classification symmetry in the fractionally charged quark model, then the gluons must be left massless.
The colours of quarks as new degrees of freedom
2011
The origin of the colours of quarks has been explored and the number of colours equal to three has been derived from the fractal properties suggested in the statistical model.The quark gluon coupling constant has been reproduced and the properties of the intrinsic electric charges of quarks have also been studied.
The Origin of the Color Charge into Quarks
Journal of High Energy Physics, Gravitation and Cosmology
Showing the origin of the mass in an additional coupling between field quantum oscillators, we formulate a hypothesis of a geometrical structure of the oscillators of "fields-particles". In this way, we define the possible structure of quarks and hadrons (as the proton). This hypothesis is reasonable if one admits field oscillators composed by sub-oscillators at semi-quantum (IQuO) and in which a degree of internal freedom is definable. Using the IQuO model, we find the origin of the sign of electric charge in to particles and, in quarks, the isospin, the strangeness and colour charge. Finally, we formulate the structure of the gluons and the variation modality of the colour charge in quarks.
The Global Colour Model of QCD for Hadronic Processes - a Review
2000
The global colour model (GCM) of QCD is a quark-gluon quantum field theory that very successfully models QCD for low energy hadronic processes. An effective gluon corre- lator models the interaction between quark currents. Functional integral calculus allows the GCM to be hadronised. The dominant configuration of the hadronic functional inte- grals is revealed to be the constituent quark effect,
How do constituent quarks arise in QCD? Perturbation theory and the infra-red
Nuclear Physics B - Proceedings Supplements, 1997
We motivate the use of dressed charges by arguing that such objects are needed to describe, e.g., constituent quarks and, in general, physical charged states in gauge theories. We give a short introduction to dressings in both QED and QCD. We put special emphasis on the infra-red properties of a moving dressed charge. To be more precise, we demonstrate that the one loop propagator of a relativistic dressed charge can be renormalized in the mass shell scheme with no infra-red divergence showing up.
This article gives the potential energy function of quark in the gluon field, derives the wave function of quark in stationary state and the quark confinement and asymptotic freedom, shows that a quark is composed of two different color gluons, expounds the formation mechanism of the quark confinement and asymptotic freedom and the physical substance of “colors” of quark, and discusses the stability of hadrons in the end.
The static quark potential from the gauge invariant Abelian decomposition
Physics Letters B, 2014
We investigate the relationship between colour confinement and topological structures derived from the gauge invariant Abelian (Cho-Duan-Ge) decomposition. This Abelian decomposition is made imposing an isometry on a colour field n which selects the Abelian direction; the principle novelty of our study is that we have defined this field in terms of the eigenvectors of the Wilson Loop. This allows us to establish an equivalence between the path ordered integral of the non-Abelian gauge fields with an integral over an Abelian restricted gauge field which is tractable both theoretically and numerically in lattice QCD. By using Stokes' theorem, we can relate the Wilson Loop in terms of a surface integral over a restricted field strength, and show that the restricted field strength may be dominated by topological structures, which occur when one of the parameters parametrising the colour field n winds itself around a non-analyticity in the colour field. If they exist, these objects will lead to an area law scaling for the Wilson Loop and provide a mechanism for quark confinement. We search for these structures in quenched lattice QCD. We perform the Abelian decomposition, and find that the restricted field strength is dominated by peaks on the lattice. Wilson Loops containing these peaks show a stronger area-Law and thus provide the dominant contribution to the string tension.