Gauge Theory Of Interactions Research Articles

Are four-fermion operators relevant for the fermion mass problem?

Four-fermion operators may have large anomalous scaling and become relevant operators in some strongly interacting gauge theories. We present a detailed model which illustrates some of the implications of such operators for the generation of quark and lepton masses. Such operators would originate at high scales where quarks and leptons experience a new strong interaction, but no unbroken technicolor interaction is required. The breakdown of both the new gauge symmetry and electroweak gauge symmetry is associated with a dynamical TeV mass for fourth family quarks. Among the new physics signatures are anomalous (chromo)magnetic moments and their flavor-changing counterparts.

Quark masses and chiral symmetry.

I discuss the global structure of the strongly interacting gauge theory of quarks and gluons as a function of the quark masses and the CP violating parameter $\theta$. I concentrate on whether a first order phase transition occurs at $\theta=\pi.$ I show why this is expected when multiple flavors have a small degenerate mass. This transition can be removed by sufficient flavor-breaking. I speculate on the implications of this structure for Wilson's lattice fermions.

Field dependent gauge couplings in locally supersymmetric effective quantum field theories

We investigate the field dependence of the gauge couplings of locally supersymmetric effective quantum field theories. We find that the Weyl rescaling of supergravity gives rise to Wess-Zumino terms that affect the gauge couplings at the one-loop level. These Wess-Zumino terms are crucial in assuring supersymmetric consistency of both perturbative and non-perturbative gauge interactions. At the perturbative level, we distinguish between the holomorphic wilsonian gauge couplings and the physically-measurable momentum-dependent effective gauge couplings; the latter are affected by the Konishi and the super-Weyl anomalies and their field-dependence is non-holomorphic. At the non-perturbative level, we show how consistency of the scalar potential generated by infrared-strong gauge interactions with the local supersymmetry requires a very specific form of the effective superpotential. We use this superpotential to determine the dependence of the supersymmetric condensates of a strongly interacting gauge theory on its (field-dependent) wilsonian gauge coupling and the Yukawa couplings of the matter fields. The article concludes with the discussion of the field-dependent non-perturbative phenomena in the context of string unification.

A Viable Model of Locally Anisotropic Space-Time and the Finslerian Generalization of the Relativity Theory

The work is devoted to the construction of a viable model of locally anisotropic, i.e. Finslerian, space-time and to the generalization, on this basis, of the relativistic theory of gravitation. Arguments in favour of this model are considered. From physical considerations the concrete form of the Finslerian metric has been reconstructed and within the framework of the correspondence principle a formalism of the theory has been developed. The approach suggested is aimed at developing unified gauge theories of all fundamental interactions. Much attention is given to the nontrivial physical manifestations of local space anisotropy and to the possibility of its experimental detection.

Quantum mechanics: an introduction, by Walter Greiner. Pp 347. DM68. 1989. ISBN 3-540-18755-3 (Springer)

Quantum Dynamics is a major survey of quantum theory based on Walter Greiner's long-running and highly successful course at the University of Frankfurt. The key to understanding in quantum theory is to reinforce lecture attendance and textual study by working through plenty of representative and detailed examples. Firm belief in this principle led Greiner to develop his unique course and to transform it into a remarkable and comprehensive text. The text features a large number of examples and exercises involving many of the most advanced topics in quantum theory. These examples give practical and precise demonstrations of how to use the often subtle mathematics behind quantum theory. The text is divided into five volumes: Quantum Mechanics I - An Introduction, Quantum Mechanics II - Symmetries, Relativistic Quantum Mechanics, Quantum Electrodynamics, Gauge Theory of Weak Interactions. These five volumes take the reader from the fundamental postulates of quantum mechanics up to the latest research in particle physics. Volume 1, Quantum Mechanics I - An Introduction, lays the foundation for the rest of the course. Starting from black-body radiation, the photo-electric effect and wave-particle duality, Greiner goes on to discuss the uncertainty relations, spin and many-body systems, then discusses applications to the hydrogen atom and the Stern-Gerlach and Einstein-de Haas experiments. The mathematics of representation theory, S-matrices, perturbation theory, eigenvalues and hypergeometric differential equations are presented in detail, with 84 fully and carefully worked examples and exercises to consolidate the material. Volume 2 presents a particularly appealing and successful theme in advanced quantum mechanics - symmetries. After a brief introduction to symmetries in classical mechanics, the text turns to their relevance in quantum mechanics, the consequences of rotation symmetry and the general theory of Lie groups. The Isospin group, hypercharge, SU (3) and their applications are all dealt with in depth before a chapter on charm and SU (3) leads to the frontiers of research in particle physics. Almost a hundred detailed, worked examples and problems make this a truly unique text on a fascinating side of modern physics.

On the composition of the lightest nucleus

The composition of the lightest nucleus, the nucleon, is discussed here in terms of relativistic quark-gluon models which are based on the non-abelian gauge theory of the strong interactions, Quantum Chromodynamics. This composition of the nucleon is manifest in momentum-dependent meson-nucleon vertex functions which are necessary for a detailed understanding of the nucleon-nucleon force. The precise knowledge of the nucleon-nucleon interaction is a prerequisite for any progress in the field-theoretic description of the nuclear force. I emphasize the role of the neutron in the investigation of the internal spin and charge distribution of the nucleon.

CP violation in electroweak interactions

We present a general method to test the CP properties of gauge theories of the electroweak interactions. We consider both the case of spontaneous CP violation and of explicit CP breaking. The method enables one to derive in a simple way CP restrictions on the couplings of a given Lagrangian and to express these restrictions in terms of weak-basis invariants which define the CP properties of the Lagrangian. We consider in detail the case of the standard model and some of its simplest extensions.

BRST construction of interacting gauge theories of higher spin fields

The problem of constructing consistent interacting theories of an infinite tower of high-spin fields is formulated in terms of a field φ( X) defined on a finite- or infinite-dimensional extended space-time manifold M , generalizing the concept of a string-field φ[ x( σ)]. Using the techniques of BRST cohomology we first analyze the conditions under which a system of compatible wave equations for φ defines a gauge-invariant free theory without ghosts in its physical sector. The necessary and sufficient conditions for the existence of a gauge-invariant cubic interaction are then shown to take the concise form of a graded Lie algebra, on which the BRST charge acts as an exterior derivative. Witten's string-field theory is a particular realization of this algebra. The importance of a search for other realizations, possibly operating on a finite-dimensional manifold M and/or leading to an interacting theory of massless gauge fields of any spin, is stressed and commented on.

BRST construction of interacting gauge theories of higher spin fields: Luigi Cappiello, Marc Knecht, Stéphane Ouvry, and Jan Stern. Division de Physique Théorique, Institut de Physique Nucléaire, F-91406 Orsay Cedex, France

BRST construction of interacting gauge theories of higher spin fields: Luigi Cappiello, Marc Knecht, Stéphane Ouvry, and Jan Stern. Division de Physique Théorique, Institut de Physique Nucléaire, F-91406 Orsay Cedex, France

Canonical quantization of nonabelian gauge theories in two dimensions

The canonical quantization of vector and chiral nonabelian gauge theories is performed, using the bosonization procedure. The gauge current commutators are computed and a close relation between the vector and chiral interacting gauge theories is shown to exist for a particular value of the regularization dependent parameter a.

The variational approach to the extended Glashow–Weinberg–Salam model

A generalization of the variational approach to the SU(2) × U(1) × U(1) gauge theory of electroweak interactions based on canonical quantization is presented.

Description of weak decays of D and B mesons

In this review, the theoretical treatment of D and B meson decays is summarized in the framework of the standard gauge theory of electroweak and strong interactions. The emphasis lies on the description of exclusive semileptonic and hadronic decays. A consistent phenomenological picture based on the valence quark approximation and the factorization hypothesis is developed. The importance of rare B decays for testing the standard model is also discussed.

Field Theory in Particle Physics, Volume 1 and Quantum Field Theory and Gauge Theories of Strong and Electroweak Interactions

<i>Field Theory in Particle Physics, Volume 1</i> and <i>Quantum Field Theory</i> and <i>Gauge Theories of Strong and Electroweak Interactions</i>

Massive neutrinos and neutrino oscillations

The theory of neutrino mixing and neutrino oscillations, as well as the properties of massive neutrinos (Dirac and Majorana), are reviewed. More specifically, the following topics are discussed in detail: (i) the possible types of neutrino mass terms; (ii) oscillations of neutrinos (iii) the implications of $\mathrm{CP}$ invariance for the mixing and oscillations of neutrinos in vacuum; (iv) possible varieties of massive neutrinos (Dirac, Majorana, pseudo-Dirac); (v) the physical differences between massive Dirac and massive Majorana neutrinos and the possibilities of distinguishing experimentally between them; (vi) the electromagnetic properties of massive neutrinos. Some of the proposed mechanisms of neutrino mass generation in gauge theories of the electroweak interaction and in grand unified theories are also discussed. The lepton number nonconserving processes $\ensuremath{\mu}\ensuremath{\rightarrow}e\ensuremath{\gamma}$ and $\ensuremath{\mu}\ensuremath{\rightarrow}3e$ in theories with massive neutrinos are considered. The basic elements of the theory of neutrinoless double-$\ensuremath{\beta}$ decay are discussed as well. Finally, the existing data on neutrino masses, oscillations of neutrinos, and neutrinoless double-$\ensuremath{\beta}$ decay are briefly reviewed. The main emphasis in the review is on the general model-independent results of the theory. Detailed derivations of these are presented.

New precision measurements of the muonic [formula omitted] X-ray transition in 24Mg and 28Si: Vacuum polarisation test and search for muon-hadron interactions beyond QED

Motivated by the importance of scalar particles in the current work on gauge theories of fundamental interactions, we have performed an improved muonic-atom experiment to search for long-range muon-hadron interactions. We remeasured the wavelengths of the 3 d 5 2 −2 p 3 2 X-ray transitions in 24Mg and 28Si with the bent-crystal spectrometer at the SIN muon channel. The relative difference between the X-ray wavelength λ exp and the theoretical value as obtained from QED calculations, averaged over the two elements, is λ exp -λ QUED /λ QUED = (-0.2 +-3.1) × 10 6 Assuming the validity of the QED calculations, we can put limits on an additional muon-nucleon interaction: If such an interaction were mediated, for example, by a scalar or vector (isoscalar) boson with a mass smaller than about 1 MeV, the corresponding coupling constant is g μ g N ⩽ 0.8 × 10 −6 × e 2. Alternatively, if additional muon-hadron interactions are negligible, our result corresponds to a 950 ppm test of the vacuum polarisation effect in QED. The result can also be interpreted as a 3 ppm measurement of the negative muon mass.

Energy‐Momentum Tensor and Equations of Motion of Glashow‐Salam‐Weinberg‐Theory in Curved Space‐Time

AbstractThe equations of motion of the unified gauge theory of weak and electromagnetic interactions, when minimally coupled to the gravitational field, are given.

Gauge Theories of the Strong, Weak and Electromagnetic Interactions

<i>Gauge Theories of the Strong, Weak and Electromagnetic Interactions</i>

Approximate weinberg mixing

We present a model of the weak interactions in which a custodial symmetry that is not an invariance of the starting Lagrangian emerges in the effective low-energy sector of the theory. This symmetry maintains the relationMw=Mz cosθw to all orders in the Higgs self-couplings to any required degree of accuracy, while leaving the quark mass spectrum completely unconstrained. The model is a local left-right symmetric chiral flavor gauge theory of the electroweak interactions in which the symmetry is spontaneously broken by fundamental Higgs fields which transform the same way under the chiral group as fermion Dirac and Majorana masses.

Spin gauge theory of the first generation

In a previous paper, we introduced the concept of a spin gauge theory. Here we present a specific non-Abelian spin gauge theory of the electrostrong interactions of the particles of the first generation. The theory for the massless Dirac electron and Pauli neutrino is based upon a particular (16×16) representation of an eight-dimensional Clifford algebra, which is then transformed by an inner automorphism into the theory describing «up» and «down» dion spinors corresponding to electric charges ±1/3e and ±2/3e. The transformation of the dion Lagrangian to three other representations of the algebra produces dion spinors of three «colours». Three generators of the gauge transformation form aSU1,1 group, defining a neutral-vector-potential interaction and two unusual interactions with pseudovector potentials, corresponding to bosons with charges ±1/3e. The other generators define neutral vector potentials which mix with that generated fromSU1,1 to give the electromagnetic potential and a «strong» neutral potential. Finally we discuss the results obtained, problems which remain to be solved, and the aims of further work.

Spin gauge theory of the first generation

In a previous paper, we introduced the concept of a spin gauge theory. Here we present a specific non-Abelian spin gauge theory of the electrostrong interactions of the particles of the first generation. The theory for the massless Dirac electron and Pauli neutrino is based upon a particular (16×16) representation of an eight-dimensional Clifford algebra, which is then transformed by an inner automorphism into the theory describing «up» and «down» dion spinors corresponding to electric charges ±1/3e and ±2/3e. The transformation of the dion Lagrangian to three other representations of the algebra produces dion spinors of three «colours». Three generators of the gauge transformation form aSU1,1 group, defining a neutral-vector-potential interaction and two unusual interactions with pseudovector potentials, corresponding to bosons with charges ±1/3e. The other generators define neutral vector potentials which mix with that generated fromSU1,1 to give the electromagnetic potential and a «strong» neutral potential. Finally we discuss the results obtained, problems which remain to be solved, and the aims of further work.