Showing papers on "Electroweak interaction published in 1987"
TL;DR: In this paper, the authors proposed a new scenario of the baryon asymmetry generation in the framework of standard electroweak theory which is based on the recent observation that anomalous Baryon number violating processes are nonsuppressed at high temperatures.
519 citations
TL;DR: In this article, the authors characterize a class of composite models in which the quarks and leptons and technifermions are built from fermions bound by strong gauge interactions, and they show that the compositeness scale must be between ≈ 1 TeV and ≈ 2.5 TeV, giving rise to observable deviations from the standard electroweak interactions.
510 citations
473 citations
TL;DR: In this paper, it was shown that QCD originates in the chiral color group SU(3)×SU(3), and that the scale of chiral-color breaking is similar to the electroweak mass scale.
250 citations
TL;DR: In this article, the cosmon is assumed to be the Goldstone boson of dilatation and to be broken spontaneously near the Planck scale, which drives the cosmological constant to zero, provided that the energy-momentum trace is purely anomalous.
228 citations
TL;DR: In this paper, the upper bound on the Higgs boson mass was derived from the condition that baryon asymmetry produced during the electroweak phase transition should not be diluted by the anomalous electroweak Baryon number nonconserving processes.
Abstract: We determine the upper bound on the Higgs boson mass from the condition that baryon asymmetry produced during the electroweak phase transition should not be diluted by the anomalous electroweak baryon number non-conserving processes. The value is insensitive to the mass of t-quark and equal to 45 GeV, slightly depending on the magnitute of the preexponential factor in the rate of the B non-conservation. This gives also upper bound on the top quark mass mt<80 GeV.
157 citations
TL;DR: In this paper, the two-loop corrections to the ϱ-parameter and the vector boson mass shifts due to a heavy fermion doublet were calculated and improved limits on the allowed mass difference within a doublet.
112 citations
TL;DR: In this paper, the necessary conditions for the survival of baryon asymmetry generated in the B -L conserving leptoquark decays were formulated, and they showed that equilibrium anomalous electroweak B -nonconserving interactions do not wash out all the baryone asymmetry if there is no mixing in the leptonic sector.
109 citations
TL;DR: In this article, the cross-section ratio of neutral-current and charged-current semileptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result:Rv=0.3093±0.0031 for hadronic energy larger than 4 GeV.
Abstract: The cross-section ratio of neutral-current and charged-current semileptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result:Rv=0.3093±0.0031 for hadronic energy larger than 4 GeV. From this ratio we determined the electroweak mixing angle sin2θW, wheremc is the charm-quark mass in GeV/c2. Comparison with direct measurements ofmw andmz determines the radiative shift of the intermediate boson mass Δr=0.077±0.025(exp.)±0.038(syst.), in agreement with the prediction. Assuming the validity of the electroweak standard theory we determined ϱ=0.990−0.013(mc−1.5)±0.009(exp.)±0.003(theor.).
97 citations
TL;DR: In this article, the decays W → ev and Z → e + e −, using the UA2 detector at the CERN pp Collider, correspond to an integrated luminosity of 142 nb −1 at a centre-of-mass collision energy √ s =546 GeV, and 768 nb−1 at √ n =630 GeV.
88 citations
TL;DR: In this article, the authors constructed the coherent quantum state corresponding to a saddle-point solution of the standard electroweak theory (the "sphaleron") as obtained by Klinkhamer and Manton, and the matrix element connecting this state to a q q state was then shown to depend crucially on a dimensionless strength gnAn of the sum of tree amplitudes for q q →n W, n≃55.
TL;DR: In this paper, the nonlinear evolution equations for Yukawa coupling matrices are discussed in the context of the double Higgs and supersymmetric model of electroweak interactions, and approximate analytical solutions for the non-linear evolution of masses and mixing angles are found.
TL;DR: In this paper, the complete electromagnetic and weak radiative corrections of O (α3) to neutral current deep inelastic lepton proton scattering at HERA energies in the framework of the quark parton model were calculated.
TL;DR: In this paper, the full one-loop electroweak radiative corrections to the longitudinal polarization asymmetry on the toponium resonance were evaluated and it was shown that to the order of interest the results are unaffected by QCD corrections.
TL;DR: An ambidextrous electroweak interaction model with SU(2L×SU(2)R×U(1) gauge symmetry is described in this article, in which the conventional quarks and leptons are accompanied by a set of new fermions that transform as singlets of SU( 2L×S2R)R. The model has only two doublets of Higgs scalars.
Abstract: An ambidextrous electroweak interaction model with SU(2)L×SU(2)R×U(1) gauge symmetry is described in which the conventional quarks and leptons are accompanied by a set of new fermions that transform as singlets of SU(2)L×SU(2)R. The model has only two doublets of Higgs scalars. The masses of all known quarks and leptons result from the see-saw mechanism between the conventional fermions and the new “singlet” fermions. Neutrino neutral current interactions are identical to those of the standard SU(2)L×U(1) model. The singlet fermion masses lie in the 100-GeV to 1-TeV range to be probed by the oncoming accelerators of the 1990’s.
TL;DR: A massive charged scalar, such as is present in a two Higgs-doublet electroweak theory, can alter the nature of top-quark decay, ensuring that the top quark would not have been detected at hadron colliders.
TL;DR: In this paper, an ambidextrous electroweak interaction model with SU(2L×SU(2)R×U(1) gauge symmetry is described, in which the conventional quarks and leptons are accompanied by a set of new fermions that transform as singlets of SU( 2L× SU(R)R. The model has only two doublets of Higgs scalars.
TL;DR: It is shown that gluon fusion via quark and scalar-quark loops dominates the usual electroweak quark-antiquark annihilation process if there exist sufficiently heavy quarks or scalar quarks.
Abstract: We discuss the pair production of charged Higgs bosons in high-energy hadron collisions, concentrating on supersymmetric models with two Higgs doublets. We show that gluon fusion via quark and scalar-quark loops dominates the usual electroweak quark-antiquark annihilation process if there exist sufficiently heavy quarks or scalar quarks.
TL;DR: In this paper, a generalization of the standard electroweak model into the sector of the weak vector boson self-interactions is undertaken, based on dimensionless couplings, electromagnetic gauge invariance and a global SU(2) WI symmetry.
TL;DR: In this article, a lattice investigation of the bayron asymmetry generation within the framework of the standard electroweak theory was conducted, and it was shown that transitions between different gauge sectors are unsuppressed at temperatures larger than the critical temperature corresponding to the breaking of the SU (2) × U (1) group.
CERN1
TL;DR: In this paper, the authors derive upper bounds on Yukawa couplings in low-energy dynamical models inspired by the superstring and draw attention to the processes which give the best bounds on new Yukawa coupling and which are those where novel superstring effects might first appear as experimental sensitivity is improved.
Abstract: Superstring models compactified on Calabi–Yau manifolds contain additional matter fields and gauge bosons beyond those in the Standard Model. The new matter and gauge couplings would make additional contributions to conventional electroweak processes, generate extra flavor-changing neutral interactions, and mediate new interactions leading to proton decay and neutrino masses. We use the phenomenological constraints on such effects to derive upper bounds on Yukawa couplings in low-energy dynamical models inspired by the superstring. We draw attention to the processes which give the best bounds on new Yukawa couplings, and which are those where novel superstring effects might first appear as experimental sensitivity is improved. Our bounds are not sufficient to exclude most superstring models with additional light particles, but do suggest that some couplings are too small to realize certain scenarios for symmetry breaking by radiative corrections.
TL;DR: In this paper, the authors set upper limits for rare exclusive decays of B mesons arising from higher order processes in the standard model of electroweak interactions via "penguin diagrams" in B decay.
TL;DR: This work considers the Drell-Yan production of an extra Z boson from the E/sub 6/ electroweak gauge group in pp-bar and pp colliders and discusses how to determine this mixing by examining the extra-Z-boson couplings to fermions through its decay modes and forward-backward asymmetries.
Abstract: We consider the Drell-Yan production of an extra Z boson from the E/sub 6/ electroweak gauge group in pp-bar and pp colliders. If there is only one extra Z at electroweak energies, it may be a mixture of the two extra U(1) groups in E/sub 6/. We discuss how to determine this mixing by examining the extra-Z-boson couplings to fermions through its decay modes and ..mu../sup +/..mu../sup -/ forward-backward asymmetries. We also discuss different mass scales of the exotic fermions present in the 27 representations of E/sub 6/.
TL;DR: One-loop corrections to the effective gauged σ-model of the large Higgs mass limit of the standard electroweak model are presented in this paper, where a significant enhancement is found for longitudinal W and Z scattering sections in the TeV center of mass energy region.
TL;DR: The possible generation of cosmological matter-antimatter asymmetry in superstring models with an intermediate mass scale via the baryon-violating decays of the higgsino with the same quantum numbers as the right-handed neutrino is analyzed in this article.
TL;DR: In this article, it was shown that the critical leptonic charge density necessary for the condensation of W-mesons in the electroweak theory is increased by heating the system.
TL;DR: In this paper, a many-particle electron-neutrino system of arbitrary density is considered within the framework of the standard model of electro-weak interactions, and the Bogolyubov method has been applied for consistent derivation of relativistic kinetic equations (RKE) for neutrinos and electrons, i including the collision integrals, as well as the contributions from the self-consistent field.
Abstract: A many-particle electron-neutrino system of arbitrary density is considered within the framework of the standard model of electro-weak interactions. The Bogolyubov method has been applied for consistent derivation of relativistic kinetic equations (RKE) for neutrinos and electrons, i including the collision integrals, as well as the contributions from the self-consistent field. It is shown that the latter is essential for neutrinos, as they acquire a small effective electric charge in the dispersive medium (plasma) to result in long-range (r−1) weak forces and some collective effects which have not been taken into account for such systems until now. It is noted that neutral currents play a dominating role in the low-energy region, since they contribute mainly to long-wave length perturbations of the electron and neutrino densities.
TL;DR: In this article, the experimental consequences of the magnino, its charged partner and associated Higgs are discussed, as well as the effect of the Higgs on the solar neutrino and missing mass problems.
TL;DR: In this paper, a spin gauge symmetry within the Clifford algebra C2.6 is shown to give the correct GSW electroweak interactions for the electron-neutrino system, and a new concept of mass is introduced, the electron mass being interpreted as an interaction with the frame field, which is proportional to the spacetime dependent Dirac matrices.
Abstract: The principles of spin gauge theories are explained. A particular spin gauge symmetry within the Clifford algebra C2.6 is shown to give the correct GSW electroweak interactions for the electron-neutrino system. A new concept of mass is introduced, the electron mass being interpreted as an interaction with the 'frame field', which is proportional to the spacetime dependent Dirac matrices ( gamma u( chi )). Including the frame field in the 'extended covariant derivative' Delta mu and calculating ( Delta mu , Delta v) gives, along with the boson Lagrangian kinetic terms, exactly the correct photon, W and Z mass matrix. Transformation of the lepton extended covariant derivative to the 'quark representation' of the Clifford algebra, which is determined by the electromagnetic coupling constants, reproduces the GSW interactions for the up and down quarks. Thus, for the first generation electroweak theory, the 'Higgs-Kibble mechanism' is replaced by the frame field concept of mass. The models studied indicate that an energy associated with the frame field is approximately three times the W boson rest mass MW. A refinement of the theory suggests a fermion mass of the order of MW.
TL;DR: A high-precision measurement of the differential cross section for Bhabha scattering is presented, and effects due to electroweak interference are observed and agree well with the predictions of the Glashow-Salam-Weinberg model.
Abstract: A high-precision measurement of the differential cross section for Bhabha scattering (e/sup +/e/sup -/..-->..e/sup +/e/sup -/) is presented. The measurement was performed with the MAC detector at the PEP storage ring of the Stanford Linear Accelerator Center, at a center-of-mass energy of 29 GeV. Effects due to electroweak interference are observed and agree well with the predictions of the Glashow-Salam-Weinberg model. The agreement between the data and the electroweak prediction rules out substructure of the electron up to mass scales of 1 TeV.