Showing papers on "Electroweak interaction published in 1983"
TL;DR: In this paper, the signature of a two-body decay of a particle of mass ∼ 95 GeV/c2 was observed, which fit well with the hypothesis that they are produced by the process p + p → Z 0 + X (with Z 0 → l + + + l − ), where Z 0 is the Intermediate Vector Boson postulated by the electroweak theories as the mediator of weak neutral currents.
733 citations
TL;DR: In this paper, the origin of quark and lepton masses is discussed in a low-energy theory of strong and electroweak interactions when the weak scale is induced via supergravity.
512 citations
TL;DR: In this article, the general structure of the minimal supersymmetric extension of the standard model of strong and electroweak interactions was investigated, and the hypothesis of a partially conserved R current suppresses also the transition μ→eγ as well as dimension-5, B -and L -conserving operators.
242 citations
TL;DR: Theoretical constraints and limits on the masses of Higgs scalars in the standard electroweak model, in electroweak models with additional Higgs doublets and in various supersymmetric models are presented in this paper.
174 citations
TL;DR: In this article, a new way to generate boson-fermion mass splittings was proposed, which does not depend on the details of the super-Higgs mechanism nor on the flat superpotential used.
136 citations
TL;DR: In this article, the effects of spin-3 2 excited quarks are considered as probes of a possible new hadronic mass-scale Λ, and a specific model is developed which describes virtual spin - 3 2 quarks of mass of O(Λ).
129 citations
TL;DR: In this paper, the renormalization of the neutral-to-charged current Fermi constant ratio arising from the new particles required in supersymmetric scheme was studied and it was shown that ϱ is insensitive to the scale of the supersymmetry mass splitting.
96 citations
TL;DR: Topological obstructions to the definition of unbroken symmetry transformations in the presence of monopoles with non-Abelian flux are exposed in this paper, and the results for color and electroweak SU(2) in the context of the SU(5) model are discussed.
Abstract: Topological obstructions to the definition of unbroken-symmetry transformations in the presence of monopoles with non-Abelian flux are exposed. Consequences for color and electroweak SU(2) in the context of the SU(5) model are discussed.
95 citations
TL;DR: In this paper, the branching ratios for Zsup0..-->..qx-bar, where q and x are quarks of different flavors, are computed using the standard model of electroweak interactions.
Abstract: Using the standard model of electroweak interactions, we compute the branching ratios for Zsup0..-->..qx-bar, where q and x are quarks of different flavor. Such processes can be distinguished from the background only when q is much more massive than x (or vice versa); these rates are insignificant unless there are four (or more) generations of quarks. Since the results are then sensitive to the unknown mixing angles and masses of undiscovered quarks, we discuss these quantities briefly. We find that some values of these parameters lead to event rates that might be detectable in an esup+esup- machine operating on the Zsup0 resonance. The appendices contain our Feynman rules and technical details of the calculation.
76 citations
TL;DR: In this paper, the authors measured a deep inelastic μ± cross section asymmetry at momentum transfers Q2 ranging from 15 to 180GeV2, which is in quantitative agreement with the WS/GIM standard electroweak model and allows to determine the muon neutral current couplings.
73 citations
CERN1
TL;DR: In this article, the leptonic sector of the electroweak theory is analyzed for massive Majorana neutrinos, where the Majorana mass lagrangian is diagonalized using polar reduction to guarantee physical positive masses independently of the CP properties or the choice of the phases of the fields.
TL;DR: In this article, the implications of the recent observation of a parity violation in atomic cesium were studied and conservative bounds for the weak charge Q W were derived, which were used to put constraints on alternatives to the standard electroweak model, involving an extra U(1) gauge group.
TL;DR: In this paper, a discussion of the predictions for the electric dipole moment of the neutron which follow from the various sources of violation of CP invariance in the theory is presented.
Abstract: One of the consequences of violation of CP invanance of the physical world is the existence of an electric dipole moment of elementary particles. The renormalization gauge theory of the electroweak and strong interactions developed during the past decade has revealed several possible sources of violation of CP invanance: direct violation of CP invariance in the Lagrangian of the electroweak interactions, spontaneous violation of CP invariance, and violation of CP invariance in the strong interactions described by quantum chromodynamics. The present review is devoted to a discussion of the predictions for the electric dipole moment of the neutron which follow from the various sources of violation of CP invariance in the theory. It includes the theoretical results obtained in the framework of gauge theory during the past decade up to the beginning of 1982. A comparison of the prediction of various gauge models with the experimental measurements of the electric dipole moment will make it possible to gain a better understanding of the nature of violation of CP invariance.
TL;DR: In this article, low-order electromagnetic corrections to deep inelastic scattering of polarized leptons by polarized nucleons are derived and investigated using a covariant method, and the sensitivity of the corrections to the choice of the structure functions is investigated.
TL;DR: In this article, the authors explore the observable consequences of supersymmetry, under the assumption that it is broken spontaneously at energies of order 300 GeV. Theories of this sort tend automatically to obey a global $R$ symmetry, which presents us with a choice among phenomenologically unacceptable alternatives.
Abstract: We explore the observable consequences of supersymmetry, under the assumption that it is broken spontaneously at energies of order 300 GeV. Theories of this sort tend automatically to obey a global $R$ symmetry, which presents us with a choice among phenomenologically unacceptable alternatives. If the $R$ symmetry is broken by scalar vacuum expectation values of order 300 GeV, there will be a semiweakly coupled light Goldstone boson, similar to an axion. If it is not broken by such vacuum expectation values but is broken by quantum-chromodynamic (QCD) anomalies, then there will be a light ninth pseudoscalar meson. If it is not broken by QCD anomalies, then the asymptotic freedom of QCD is lost at high energies, killing the hope of an eventual meeting of the electroweak and strong couplings within the regime of validity of perturbation theory. We also confront the problem of an uncomfortably light gluino. A general analysis of gaugino masses shows that the gluino mass is at most of order 1 GeV, and in many cases much less.
TL;DR: In this paper, the differential cross sections for lepton pair production in e+e- annihilation at 29 GeV have been measured and found to be in good agreement with the standard model of the electroweak interaction.
Abstract: The differential cross sections for lepton pair production in e+e- annihilation at 29 GeV have been measured and found to be in good agreement with the standard model of the electroweak interaction. With the assumption of e-μ-τ universality, the weak neutral-current couplings are determined to be ga2=0.23±0.05 and gv2=0.03±0.04. © 1983 The American Physical Society.
CERN1
TL;DR: In this paper, the colour gauge group is extended to SU(3) ⊗ SU (3) and is subsequently broken to diagonal SU( 3) c, where the fundamental fermionic constituents of the larger strong group become ordinary quarks plus new quarks with exotic quantum numbers.
CERN1
TL;DR: In this paper, the possibility of generating fermion masses through radiative corrections in the well-defined framework of SU(2)LXU(1) was investigated, but no-go theorems imply a complete tree-level description of the spectrum with at least one electroweak singlet scalar and suggest the need for new gauge interactions.
Abstract: We investigate the possibility of generating fermion masses through radiative corrections in the well-defined framework of SU(2)LX U(1). No-go theorems, however, imply a complete tree-level description of the spectrum with at least one electroweak singlet scalar and suggest therefore the need of new gauge interactions.
01 Oct 1983
TL;DR: In this paper, the role of the strong interaction of hadrons is discussed in the framework of the standard SU(3) x SU(2) x U(l) gauge theory of e1ectroweak and strong interactions.
Abstract: Weak decays of hadrons which contain a heavy quark are discussed in the framework of the standard SU(3) x SU(2) x U(l) gauge theory of e1ectroweak and strong interactions. The primary focus is on the role of the role of the strong interaction of which there are two aspects; the modifications of the effective weak Hamiltonian due to hard gluon interactions, and the impact of the light quarks and soft gluons· in hadronic bound states. Both are studied in detail. The experimental data on inclusive charm decays as well as explicit model calculations are used to develop a consistent phenomenological picture. Extrapolating these results to bottom decays, detailed predictions on the inclusive decay properties of B mesons are presented and confronted with the most recent data. Finally, the theoretical and experimental status quo of non-1eptonic two-body decays is surveyed, with the emphasis on the theoretical subtleties peculiar to exclusive decays.
TL;DR: In this article, the SU/sub 5/ model is developed for unification of weak, electromagnetic, and strong interaction, and attempts to unify the weak, strong, and electromagnetic interaction are reviewed.
Abstract: Attempts to unify the weak, electromagnetic, and strong interaction are reviewed. The SU/sub 5/ model is developed.(AIP)
TL;DR: In this paper, the authors describe the characteristics of quarks and leptons and a review of the development of models for the electroweak and the color force, reasons for considering quarks as composite particles are given.
Abstract: Following a description of the characteristics of quarks and leptons and a review of the development of models for the electroweak and the color force, reasons for considering quarks and leptons as composite particles are given. Two composite models, the preon model and the rishon model, are then discussed and possible experimental tests are considered. (KAW)
TL;DR: In this paper, the authors examined the high-energy predictions of left-right models which are consistent with constraints from low-energy data and compared the predictions of the standard electroweak gauge model to determine how well the theories can be distinguished by measurements in this mass region of the Z boson resonance.
Abstract: We examine the high-energy predictions of left-right models which are consistent with constraints from low-energy data. These are compared to the predictions of the standard electroweak gauge model to determine how well the theories can be distinguished by measurements in this mass region of the standard Z boson resonance. We find a nontrivial class of left-right models in which the lowest-mass Z is indistinguishable in mass and fermion couplings from the standard Z, but which allow a second Z boson as low as 200 GeV. We discuss the sensitivity of the lower limit on the second-Z mass to the results of the atomic parity-violation measurement and find that the newest data relaxes the mass limit in a general left-right model to M/sub Z//sub 2/> or =150 GeV.
TL;DR: The role of heavy fermions and heavy Higgs-scalars in the MW − MZ relation resulting from the one-loop-corrected μ decay width Γ(1) and its experimental data Γexp is studied in the framework of the standard electroweak theory as discussed by the authors.
TL;DR: In this article, the axial vector coupling constants were obtained in a simultaneous fit to the three differential cross sections assuming a universal weak interaction for the charged leptons, and the results were in good agreement with predictions from the standard SU(2)×U(1) model for electroweak contributions.
Abstract: Differential cross sections fore
+e−→e
+e−, τ+, τ- measured with the CELLO detector at
$$\left\langle {\sqrt s } \right\rangle = 34.2GeV$$
have been analyzed for electroweak contributions. Vector and axial vector coupling constants were obtained in a simultaneous fit to the three differential cross sections assuming a universal weak interaction for the charged leptons. The results,v
2=−0.12±0.33 anda
2=1.22±0.47, are in good agreement with predictions from the standardSU(2)×U(1) model for
$$\sin ^2 \theta _w = 0.228$$
. Combining this result with neutrino-electron scattering data gives a unique axial vector dominated solution for the leptonic weak couplings. Assuming the validity of the standard model, a value of
$$\sin ^2 \theta _w = 0.21_{ - 0.09}^{ + 0.14}$$
is obtained for the electroweak mixing angle. Additional vector currents are not observed (C<0.031 is obtained at the 95% C.L.).
TL;DR: In this article, the spectral function sum rules of the W-boson were used to derive its mass and total width, and the results may give a test on possible aspects of this model of electroweak interactions.
01 Sep 1983
TL;DR: In this article, Toroidal moments and their radii are analyzed in the context of the transverse electric part of a convection and induction current, and the results of the extraction of toroidal moments of nuclear transitions through nuclear conversion penetration parameters, the possibilities of extracting information about toroidal giant resonances, etc.
Abstract: The analytic structure and geometrical meaning of multipole expansions for systems containing convection and induction currents are illustrated in the framework of classical electrodynamics. The main attention is devoted to the expansion of the transverse electric part of the current, in which the authors have identified a third family of multipole parameters: toroidal moments and their radii. The electromagnetic properties of the simplest toroidal systems are analyzed. The connection between multipole expansions and the methods of invariant parametrizations of relativistic matrix elements of a current operator is emphasized. Some consequences and effects of the existence of these moments are pointed out in the theory of atomic and nuclear transitions. A review is made of the results achieved on the extraction of toroidal moments of nuclear transitions through nuclear conversion penetration parameters, the possibilities of extracting information about toroidal giant resonances, etc. The results are given of the study of anapoles (toroidal dipoles) in the framework of the problem of parity violation by the electroweak interactions in atomic, nuclear, quasinuclear, and quark systems.
TL;DR: In this paper, it was shown that supersymmetric QCD will exhibit parity violation if the squark partners of left and right-handed quarks are not mass degenerate, assuming that the standard electroweak effects are still the major contributor to nuclear parity violation.
TL;DR: In this paper, the authors analyzed the effects of some electroweak interaction models with a composite W at present energies and found that the width of the W into pairs of pseudoscalar bosons can be appreciable and may reduce its leptonic branching ratio by about 20%.
TL;DR: In this paper, the same experimental and theoretical constraints used to set limits on the masses of the weak bosons in the composite-model versions of electroweak mixing models are used to bound the magnetic-moment parameter of the W.
Abstract: The same experimental and theoretical constraints that are used to set limits on the masses of the weak bosons in the composite-model versions of electroweak mixing models are used to bound the magnetic-moment parameter of the W We find in general electroweak mixing schemes, ones with additional heavy isospin-1 bosons (W'), that off-diagonal weak-boson electromagnetic interactions (WW'gamma vertices) are allowed The cross section for the process q/sub i/q-bar/sub j/-->Wgamma, which has been suggested as the best way to measure the W moments, is generalized to include the effects of these off-diagonal couplings as well as arbitrary and independent W magnetic dipole and electric quadrupole moments
TL;DR: In this paper, higher-order (α3) QED contributions are compared with the γ-Z0 interference at the tree level for the difference between the two differential cross-sections.
Abstract: Higher-order (α3) QED contributions are compared with the γ-Z0 interference at the tree level for the difference between the two differential cross-sections dσ/dΩ(e∓+μ∓→e∓+μ∓) and dσ/dΩ(e∓+μ±→e∓+μ±). It is found that the γ-Z0 interference is comparable with the QED contributions at c.m. energy of 13 GeV and it is more important at higher energy.