Field theory without asymptotic particles and quarks confinement

The basic idea of a local quantum field theory is presented which should explain the quark confinement, their essentially free behavior under deep-inelastic scattering and at least part of Zweig's rule.     

Helium Afterglow without Metastable Particles

Optics and Spectroscopy - We study the afterglow of a pulsed barrier discharge in helium with a small admixture of neon (10‒2%), which creates a plasma with a low density of metastable...     

Could there be a fourth generation of quarks without more leptons?

We investigate the possibility of adding a fourth generation of quarks. We also extend the Standard Model gauge group by adding another SU(N) component. In order to cancel the contributions of the fourth generation of quarks to the gauge anomalies we must add a generation of fermions coupling to the SU(N) group. This model has many features similar to the Standard Model and, for example, includes a natural generalisation of the Standard Model charge quantisation rule. We discuss the phenomenology of this model and, in particular, show that the infrared quasi-fixed point values of the Yukawa coupling constants put upper limits on the new quark masses close to the present experimental lower bounds.     

Do quarks propagate?

Processes with coloured particles in the initial state are generally infrared divergent. We investigate the effect of this on processes with colourless particles in the initial state, when the amplitude is near an intermediate quark pole. The result is a characteristics logarithmic dependence on the “binding energy” (even though spectator interactions are taken into account), and the result is gauge-invariant. Summed to all orders, the logarithms could perhaps suppress the quark pole.     

Heavy quarks in electroproduction

The idea of an effective light-particle field theory is used to analyze the effects of heavy quarks in electroproduction. The b-quark distribution is predicted at large Q² and a systematic treatment of the changing number of quark flavors in a QCD analysis of F₂ is presented.     

Confinement model for quarks

A confinement model of hadron with its constituent quarks bound in a strong gravitational field is presented. The gravitational field plays the role of a medium having, as if, space dependent permeabilities from a fixed centre. The massless Dirac equation modified by the gravitational field is solved. The solution for the wavefunction of the quarks obtained shows the characteristic features of confinement, i.e., (i) wavefunction with higher energy states lying closer to the centre, (ii) equispaced energy levels without continuum, (iii) the quark orbits lying within a distance ∼ 10⁻¹⁴ cm, the characteristic radius of a typical hadron.     

Constituent quarks from QCD

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.     

Light quarks and instantons

Instantons and anti-instantons can profoundly influence the structure of a non-Abelian gauge theory involving N flavors of massless quarks. Interactions of the quarks with these pseudoparticles can spontaneously generate a quark mass, break the theory's SU(N) × SU(N) chiral symmetry and bind quark-antiquark pairs to form N² ? 1 Goldstone bosons. If the spontaneously generated quark mass is small, multipseudoparticle configurations can be treated in a dilute gas approximation.     

Weak interaction of quarks

A theory of weak interaction of quarks is developed in the framework of SU (2) symmetry. Expressions are obtained for the probability of decay of quarks into leptoquarks, quarks into leptons, and leptoquarks into leptons. A model is also constructed of the interaction of quarks with matter in which strong and electromagnetic interactions of quarks with matter are forbidden. In this model, the weak interaction of quarks is the main form of interaction between quarks and matter. In this connection, it is suggested that quarks should be looked for in nature in the products of their weak decay in accordance with the theory developed here.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 30–36, July, 1974.     

Thermodynamics of constituent quarks

We investigate the thermal behavior of quarks and antiquarks interacting via a temperature-dependent linear potential. The quarks are constituent quarks with dynamically generated masses from the background linear σ model.     

Heavy quarks as color sextets

It is suggested that heavy quarks, e.g. the constituents of ?(9.6),may be color sextets. Consequences for the spectrum of quarkonium states are discussed. The new particles are long-lived and possibly stable. They can decay only via new types of weak interactions.     

Constituent quarks and g 1

We review the theory and present status of the proton spin problem with emphasis on the transition between current quarks and constituent quarks in QCD. Received: 7 January 1999 / Revised version: 12 February 1999     

Pion electromagnetic polarizabilities and quarks

The electric and magnetic polarizabilities of the neutral and changed pion are calculated in a coloured quark field theory at the one-loop level. The theory has as free parameter the quark mass but our results do not depend on it. We have found that the electric polarizabilities are α_π^±=?0.04α/m_π³, α_π0=?0.4 α/m_π³. These values are compared with calculations in other models and some comments are made about the polarizability sum rules.     

Composite quarks and cabibbo mixing

We suggest that certain discrete chiral symmetries, which are remnants of axial U(1) symmetries of a more fundamental theory, may explain the origin of the relation, tan θ_c ≈- √m_d/m_s. Simple models illustrating this idea are constructed in which quarks and standard techniquarks appear as composite states made of a more fundamental set of fermions.     

Neutral currents and new quarks

We propose a unified explanation of charged and neutral current neutrino scattering data, based on a minimal model with 3 quark and 3 lepton doublets. The data force a unique p and n quark doublet structure. Our inclusive neutral current predictions for $\text{sin}{}^2\text{θ}{}_{\mathrm{<mtext>W</mtext><mtext>\; =\; </mtext><mtext>3</mtext><mtext>8</mtext>}}$ are identical to the Weinberg-Salam model, but our νp→νp predictions agree better with experiment. We make predictions for $\text{ν}\text{?}\text{p→}\text{ν}\text{?}\text{p}$, predictions physics, supernova explosions, and $\text{ψ →ν}\text{ν}\text{?}$ decay.