Showing papers on "Electroweak interaction published in 1989"
TL;DR: In this article, the method of calculating radiative corrections to the scalar potentials is reviewed, with an emphasis on renormalization group improvement of the potential, and the results are then applied to the standard model to derive stringent bounds on Higgs and fermion passes.
850 citations
TL;DR: In this paper, a new class of models with dynamical electroweak symmetry breaking is proposed, where the composite operator ψ ψ has a large anomalous dimension γm≅2 and the t quark plays an important role in the generation of W and Z boson masses.
344 citations
Book•
01 Jan 1989
TL;DR: In this article, an introduction to particle physics and cosmology is presented, with a discussion of the interaction of these two fundamental branches of physics, and recent advances beyond the standard models.
Abstract: This book is an introduction to particle physics and cosmology. It discusses the interaction of these two fundamental branches of physics, and considers recent advances beyond the standard models. Eight chapters comprise an introduction to the gauge theories of the strong and the electroweak interactions, the so-called grand unified theories, and general relativity. The other chapters address recent concepts such as composite fermions and bosons, supersymmetry, quantum gravity, supergravity, and string theory, and relate them to modern cosmology and experimental astronomy.
342 citations
TL;DR: In this article, a new method for computing and organizing electroweak radiative corrections based on an effective lagrangian and incorporating a large class of diagrams into a few simple running couplings without use of truncated renormalization group approximations is presented.
256 citations
TL;DR: In this paper, the tree level scattering amplitudes involving one external electroweak vector boson (γ,Z, or W) and up to five colored particles (any combination of quark and gluons) are presented in a form directly amenable to numerical evaluation.
184 citations
TL;DR: In this paper, Bogomol'nyi's method was used to find a static magnetic solution of the classical electroweak equations, which corresponds to a vacuum condensate of W and Z bosons.
147 citations
TL;DR: In this article, the role of the isospin structure of nuclear states in parity-violating single-arm electron scattering from nuclei is examined, and the level of precision at which one can hope to extract the underlying weak neutral current couplings in a relatively model-independent way.
128 citations
TL;DR: In this paper, the use of four gauge invariant form factors allows a dense notation of electroweak one loop effects in muon pair production frome+e−-annihilation.
Abstract: The use of four gauge invariant form factors allows a dense notation of electroweak one loop effects in muon pair production frome+e−-annihilation. These form factors may be interpreted as finite renormalizations of the muon decay constant and of the weak mixing angle. Such a formulation is well adopted for use in Monte Carlo programs. The general formulae are applied to a realistic line shape scan of theZ boson resonance. For a precise determination of theZ boson's mass and width it is sufficient to take data in the small energy region within\(\sqrt s = M_z \pm \Gamma _z /2\). Finally, it is demonstrated that a simple model independent ansatz yields nearly equally good results.
109 citations
TL;DR: The electroweak vacuum need not be absolutely stable and for certain top-quarkand Higgs-boson masses in the minimal standard model, the vacuum is instead metastable with a lifetime exceeding the present age of the Universe.
Abstract: The electroweak vacuum need not be absolutely stable. For certain top-quark and Higgs-boson masses in the minimal standard model, our vacuum is instead metastable with a lifetime exceeding the present age of the Universe. It has been suggested that a metastable vacuum is generally ruled out because high-energy cosmic-ray collisions would have long ago induced its decay. I argue that the reasoning for this conclusion is erroneous. As a consequence, upper bounds on the top-quark mass derived from stability arguments are relaxed. Also presented is an analytic method for accurately approximating the lifetime of the vacuum from the effective potential without solving for the 0(4) bounce solution numerically.
103 citations
TL;DR: In this article, a different solution of the classical electroweak field equations which is a condensate of magnetic fluxes induced by an anti-Lenz current of the charged vector bosons is presented.
86 citations
TL;DR: In this article, the authors presented complete calculations for basic observables at SLC/LEP e + e − colliders: the Z 0 cross sections, line shape and width, forward-backward and polarizat asymmetries effects of experimental cuts are explored Special emphasis is placed on the polarization asymmetry, a highly sensitive measure of electroweak couplings and the presence of heavy particles in virtual loops.
TL;DR: It is shown that there exists a process which may in certain models with multiple Higgs doublets generate a numerically acceptable asymmetry, which involves sphalerons and requires strong CP violation at temperatures larger than 1 TeV.
Abstract: The possibility is investigated that the baryon asymmetry of the Universe might have been created at the electroweak phase transition. It is shown that there exists a process which may in certain models with multiple Higgs doublets generate a numerically acceptable asymmetry. This process involves sphalerons and requires strong CP violation at temperatures larger than 1 TeV.
TL;DR: Theoretical scenarios include isosinglet neutral heavy leptons which are present in many extensions of the standard electroweak theory such as superstring inspired models as discussed by the authors, and it can occur in a two-generation model.
TL;DR: It is found that, prior to spontaneous breaking of the electroweak subgroup, the minimal Weyl representations and their charges are uniquely determined by insisting on all three known chiral gauge anomaly-free conditions in four dimensions.
Abstract: The uniqueness of the Weyl representations of the standard gauge group is reexamined. We find that, prior to spontaneous breaking of the electroweak subgroup, the minimal Weyl representations and their charges are uniquely determined by insisting on all three known chiral gauge anomaly-free conditions in four dimensions: (1) cancellation of triangular anomalies; (2) absence of the global SU(2) anomaly; and (3) cancellation of the mixed-gauge-gravitational anomaly. The uniqueness question for the left-right-symmetric group and the simple (grand-unified-theory) group are discussed from the anomalies viewpoint.
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TL;DR: A comprehensive review of the phenomenology of the conventional Higgs boson is presented in this paper, where the fundamentals of the standard model of electroweak interactions are reviewed and experimental limits on light Higgs Bosons are assessed and prospects for further experimental searches are evaluated.
Abstract: A comprehensive review of the phenomenology of the conventional Higgs boson is presented. The fundamentals of the standard model of electroweak interactions are reviewed. Experimental limits on light Higgs bosons are assessed and prospects for further experimental searches are evaluated.
TL;DR: An electroweak theory in which left-handed quarks and leptons transform as doublets under separate SU(2) gauge groups is presented, which predicts small deviations in the properties of the /ital Z/ which will be visible at the SLAC Linear Collider and the CERN collider LEP.
Abstract: We present an electroweak theory in which left-handed quarks and leptons transform as doublets under separate SU(2) gauge groups. Spontaneous symmetry breakdown results in two charged and two neutral massive vector bosons. The lightest charged and neutral gauge bosons behave like the /ital W/ and /ital Z/ of the standard SU(2)/times/U(1) electroweak model. The heavier /ital W/ and /ital Z/, which can be as light as several hundred GeV, couple primarily to quarks. Our theory predicts small deviations in the properties of the /ital Z/ which will be visible at the SLAC Linear Collider and the CERN collider LEP.
TL;DR: In this paper, the authors report the results of a new global fit to electroweak data, including the recent SLC, CDF and UA2 measurements of MW/MZ, the new CDF, and the new CHARM II measurement of δ(vμe)/δ(μe).
CERN1
TL;DR: In this paper, a phenomenological model based on a chiral lagrangian expansion to order s 2 for the scattering amplitudes of the longitudinally polarized W L and Z L gauge bosons in the case of a generic strongly interacting symmetry breaking sector is presented.
TL;DR: It is shown by explicit calculations that the rate of chiral fermion-number violation due to the axial anomaly is entirely unsuppressed at sufficiently high temperatures.
Abstract: The O(3) nonlinear \ensuremath{\sigma} model in 1+1 dimensions, modified by an explicit symmetry-breaking term, is presented as a model for baryon- and lepton-number violation in the standard electroweak theory. Although arguments based on the Atiyah-Singer index theorem and instanton physics apply to the model, we show by explicit calculations that the rate of chiral fermion-number violation due to the axial anomaly is entirely unsuppressed at sufficiently high temperatures. Our results apply to unbroken gauge theories as well and may require reevaluation of the role of instantons in high-temperature QCD.
TL;DR: A supersymmetric extension of the standard strong and electroweak gauge model has the property that light quarks and leptons acquire radiative masses as the result of the breaking of a chiral symmetry by soft supersymmetry-breaking terms.
Abstract: A supersymmetric extension of the standard strong and electroweak gauge model has the property that light quarks and leptons acquire radiative masses as the result of the breaking of a chiral symmetry by soft supersymmetry-breaking terms. This radiative mechanism is then extended to include all known quarks and leptons in the context of a supersymmetric SU(3)\ifmmode\times\else\texttimes\fi{}SU(2)\ifmmode\times\else\texttimes\fi{}U(1)\ifmmode\times\else\texttimes\fi{}U(1)' gauge model based on ${\mathrm{E}}_{6}$ particle content as the possible low-energy limit of a superstring theory.
TL;DR: In this article, a simple Lagrangian parametrization is presented where the bound states are described as gauge vector bosons of a local, nonlinearly realized, SU(2) ⊗ SU( 2) symmetry.
Abstract: The possibility that both vector and axial-vector bound states could originate from a strong interacting sector of the electroweak theory is considered. A simple Lagrangian parametrization is presented where the bound states are described as gauge vector bosons of a local, nonlinearly realized, SU(2) ⊗ SU(2) symmetry. At present the model is mostly constrained from data on W and Z masses and on neutrino-nucleon deep inelastic scattering. High energy e+e− tests are suggested where visible deviations from the standard model predictions could take place. These deviations exhibit a certain pattern which allows to distinguish the model from other theoretical frameworks. We find that precise measurements of W and Z masses and asymmetries in e+e− collisions could put strong restrictions on the parameters of the model if no appreciable deviations are found from the standard model, except for a case with the vector and axial-vector bosons degenerate in mass and coupling. General differences with respect to technicolor are pointed out.
TL;DR: It is demonstrated that when the parameters are chosen so that corrections to the electroweak $\ensuremath{\rho}$ are within experimental limits, large Corrections to the mass sum rules arise only in certain extreme regions of parameter space, corresponding to very large ratios for squark masses.
Abstract: We consider the minimal supersymmetric extension of the standard model, and compute the corrections to Higgs-boson-mass sum rules that are possibly sensitive to the large mass of the sfermion sector and/or to large trilinear Higgs-boson-sfermion-sfermion Yukawa couplings. We demonstrate that when the parameters are chosen so that corrections to the electroweak $\ensuremath{\rho}$ are within experimental limits, large corrections to the mass sum rules arise only in certain extreme regions of parameter space, corresponding to very large ratios for squark masses.
TL;DR: In this article, the authors presented analytical results on electroweak radiative corrections for neutral-current deepinelastic electron proton scattering at HERA energies and single photon bremsstrahlung is included without cuts.
Abstract: Analytic results are presented on electroweak radiative corrections for neutral-current deepinelastic electron proton scattering at HERA energies. Single photon bremsstrahlung is included without cuts.
TL;DR: In this article, nuclear beams with energies of several TeV per nucleon are considered as carriers of intense fields of photons in the energy range up to 100 GeV, and cross sections for intermediate boson and Higgs production by two-photon collisions are predicted to be in the nanobarn range.
Abstract: Nuclear beams with energies of several TeV per nucleon are considered as carriers of intense fields of photons in the energy range up to 100 GeV. Cross sections for intermediate boson and Higgs production by two-photon collisions are predicted to be in the nanobarn range. Production of heavy neutral particles in peripheral collision could be easily detectable because of low background.
TL;DR: In this paper, the reduction of couplings in the standard model is ameliorated and updated: a new method of calculating the electroweak corrections is developed, two-loop effects are estimated and recent experimental values of the strong coupling and the Weinberg angle are incorporated in the explicit calculation of the mass relations.
TL;DR: In this article, the authors investigated the dependence of all processes with external HZγ, Hγγ or H-gluon-gluon on the parameters of supersymmetry, and found that SUSY rates are increased or decreased by up to three orders of magnitude compared to the rates predicted by the standard model.
TL;DR: In this article, a spin gauge theory describing fundamental fermions and their electroweak and gravitational interactions is proposed, modelled on an eight-dimensional curved manifold M and using its associated Clifford algebra.
Abstract: A spin gauge theory describing fundamental fermions and their electroweak and gravitational interactions is proposed. It is modelled on an eight-dimensional curved manifold M and uses its associated Clifford algebra. The elements of the algebra are represented by 16*16 matrices and the fermions are represented by sixteen-component column vectors. The frame field is introduced as a result of factorising the fermion mass term in the Lagrangian density and is included in an extended covariant derivative. The usual gauge theoretic technique of defining free bosonic Lagrangians from the fermion covariant derivative, when applied to the extended covariant derivative, gives the correct mass matrix for the photon, W and Z bosons, together with the Einstein-Hilbert gravitational Lagrangian density modified at short distances by a term quadratic in the curvature coefficients. Transformation of the Lagrangian by an inner automorphism of the Clifford algebra gives the correct mass and interaction terms for the up and down quarks.