Showing papers on "Electroweak interaction published in 1986"
TL;DR: In this paper, the first two terms of the effective lagrangian were constructed in an expansion in powers of 1/Λ and studied systematically possible effects of new interactions such as anomalous magnetic moments, deviations from universality in weak interactions and rare processes.
2,023 citations
TL;DR: In this article, an effective low-energy lagrangian of composite scalar, pseudoscalar, vector and axial-vector mesons was derived by bosonization of an extended Nambu-Jona-Lasinio type of quark model with explicit breaking of chiral U (n) × U(n) symmetry.
392 citations
TL;DR: In this article, a renormalization scheme for the electroweak standard model is presented in which the electric charge and the masses of the gauge bosons, Higgs particle and fermions are used as physical parameters.
Abstract: A renormalization scheme for the electroweak standard model is presented in which the electric charge and the masses of the gauge bosons, Higgs particle and fermions are used as physical parameters. The photon is treated such that quantum electrodynamics is contained as a simple substructure. Field renormalization respecting the gauge symmetry gives finite propagators and vertex functions. The Ward identities between the Green functions of the unphysical sector allow a renormalization that maintains the simple pole structure of the propagators in the t'Hooft-Feynman gauge. We give a complete list of self energies and all renormalization constants also in the unphysical Higgs and ghost sector. Explicit results are given for the renormalized self energies, vertex functions and boxes that enter the evaluation of 1-loop radiative corrections to fermionic processes. We calculate the 1-loop radiative corrections to purely leptonic reactions like $\mu$ decay, $
u \mu \mu e$ scattering and $\mu$ pair production in $e^+ e^−$ annihilation. A test of the standard model is performed by comparing these low energy data with the results of the $p \bar{p}$ collider experiments for the W and Z boson masses.
352 citations
Journal Article•
261 citations
TL;DR: In this paper, the electroweak radiative corrections to the partial decay widths of the Z-boson into a pair of leptons or quarks have been calculated in the standard theory.
182 citations
CERN1
TL;DR: In this paper, the authors developed a strategy for extracting low-energy phenomenological four-dimensional physics from the superstring, emphasizing key ingredients in the construction of a realistic model based on Calabi-Yau compactification.
154 citations
TL;DR: In this article, an upper bound for the evaporation rate of Q-balls in extended electroweak models with scalar fields carrying lepton number was derived. But this decay process takes place only on the surface of the object, not in the interior.
150 citations
TL;DR: In this paper, a bound on the Higgs isosplitting of about 7mZ follows from current deep inelastic νμ, ν μ data, assuming degenerate masses for the neutral scalars, and precise measurements of mZ, mW and sin2 ζW with an accuracy of 1mZ or less.
112 citations
TL;DR: The cross section ratio of neutral-current and charged-current semi-leptonic 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 as discussed by the authors.
95 citations
TL;DR: In this article, the SU(2) Higgs model with scalar doublet field is numerically investigated on lattices with size between 8 4 and 12 4, and masses and zero momentum couplings are determined at several points of the three-dimensional coupling parameter space.
83 citations
TL;DR: Sensitive measurements in a simple, reliably computable atom are in quantitative agreement with the standard electroweak theory and put stringent constraints on alternative models.
Abstract: Recent optical experiments have demonstrated cases in which mirror symmetry in stable atoms is broken during absorption of light. These results, which are in contradiction with quantum electrodynamics, support the theory of unification of the electromagnetic and weak forces. The interpretation of these experimental results is based on exchanges of weak neutral Z 0 bosons between the electrons and the nucleus of the atom. The information obtained from low-energy experiments is different from, but complementary to, the results of high-energy experiments. Sensitive measurements in a simple, reliably computable atom are in quantitative agreement with the standard electroweak theory and put stringent constraints on alternative models. Attaining sufficient accuracy in the experiments and the computations for the electroweak radiative corrections to manifest themselves is now the challenge for experimenters and theorists.
TL;DR: In this article, the electroweak radiative corrections to the decay widths of the W-boson were calculated in the standard theory and the results were presented in terms of an electroweak form factor.
Abstract: The electroweak radiative corrections to the decay widths of theW-boson, Γ
$$(W \to l\bar v,\bar ud,\bar cs)$$
, have been calculated in the standard theory The results are presented in terms of an electroweak form factorρ
W
and their dependence onm
t
, andM
H
(masses oft-quark and higgs boson) is studied Typically,ρ
W
−1 is of an order of one percent The differenceρ
−ρ
′
is negligible, 0046% The calculational scheme used is described in detail
TL;DR: In this article, it was shown that small intervals between atomic levels of opposite parity in rare-earth atoms cause the enhancement of P- and T-nonconserving effects, which is of interest for the determination of the electroweak mixing parameter sin2θ, and for the study of anapole (P-odd) and magnetic quadrupole nuclear moments.
Abstract: Small intervals between atomic levels of opposite parity in rare-earth atoms cause the enhancement ofP- andT-nonconserving effects. It is of interest for the determination of the electroweak mixing parameter sin2θ, and for study of anapole (P-odd) and magnetic quadrupole (P- andT-odd) nuclear moments.
TL;DR: It is proposed that a dynamical mass for a fourth family of quarks is responsible for breaking of the weak interactions, and for breaking the extended-technicolor interactions which provide mass to the third family, which greatly simplifies the extended technicolor sector and avoids fermions with exotic quantum numbers.
Abstract: It is proposed that a dynamical mass for a fourth family of quarks is responsible for breaking of the weak interactions, and for breaking of the extended-technicolor interactions which provide mass to the third family. This greatly simplifies the extended technicolor sector and avoids fermions with exotic quantum numbers. A technicolor sector is still required, but it is lighter than usual. The most-attractive-channel hypothesis for symmetry breakdown is relied on.
TL;DR: In this article, the effects of the additional Higgs bosons in the radiative corrections to the leptonic processes were investigated in the 1-loop renormalization of the SU(2)×U(1) electroweak gauge theory with two Higgs doublets.
Abstract: The 1-loop renormalization of theSU(2)×U(1) electroweak gauge theory with two Higgs doublets is performed in the on-shell scheme with finite self energies and vertices. Assuming different vacuum expectation values for the scalar doublets, which yield enhanced Yukawa couplings to fermions, we calculate the effects of the additional Higgs bosons in the radiative corrections to the leptonic processes:μ-decay,vμe-scattering, ande+e−→μ+μ−,τ+τ− with longitudinal polarization at PETRA and LEP/SLC energies. It is found that large effects occur in theMW−MZ mass relation, the determination of sin2θw from\(\sigma (v_\mu e)/\sigma (\bar v_\mu e)\) and thee+e− forward-backward and polarization asymmetries, if either the charged Higgs or the additional neutral scalar/pseudoscalar are heavy. Enhancement effects and effects of light neutral bosons can better be observed in thee+e−→τ+τ− integrated cross section.
TL;DR: In this article, the renormalization scheme dependence of electroweak parameters shifts is used to estimate uncertainties due to higher order effects, taking care of a systematic leading log summation.
Abstract: The renormalization scheme dependence of electroweak parameters shifts is used to estimate uncertainties due to higher order effects. Parameter shifts are calculated from weakly scheme dependent quantities, taking care of a systematic leading log summation. A “non-standard” definition of sin2θW is also considered which is to be used if the ρ-parameter is kept as free parameter. Results for the leptonic decay widths of the vector bosons are also given.
TL;DR: It is pointed out that it is possible to pick a gauge where the nonpolynomiality disappears and the resulting theory is power-counting renormalizable and unitary.
Abstract: We present a variant of the Stueckelberg formalism for Yang-Mills theory where the Stueckelberg scalar field is eliminated in favor of the gauge potential. Normally this leads to nonpolynomial interactions. However, we point out that it is possible to pick a gauge where the nonpolynomiality disappears and the resulting theory is power-counting renormalizable and unitary. This procedure allows one to construct an electroweak model without the Higgs boson.
CERN1
TL;DR: In this article, the magnetic moment of the weak boson W was measured at the Tevatron collider with a 2TeV energy √s = 2.5TeV by applying experimentally feasible cuts.
CERN1
TL;DR: In this paper, extensions to the standard electroweak model which contain new vector-like fermions at the Fermi scale are considered as a source of CP violation. And they find that the new contributions to |e′/e| range typically from 10 −3 to 10 −2 when they require that the corresponding contributions to e saturate its experimental value.
TL;DR: In this article, the lowest-order radiative corrections to the reaction e + + e − → μ + + + μ − are analyzed in the standard SU(2) × U(1) electroweak theory.
TL;DR: The observed rise in the cross section at higher energies is consistent with the electroweak prediction for a Z-italic/sup 0/ mass of 93 GeV, and some unusual muon inclusive events are described.
Abstract: We use the reaction e-italic/sup +/e/sup -/..-->..hadrons, in the Mark J detector at the DESY electron-positron collider PETRA, to determine the hadronic cross section up to 46.78 GeV. The production of a top quark with a charge equal to (2/3) is excluded up to 46.6 GeV with 95% C.L. The observed rise in the cross section at higher energies is consistent with the electroweak prediction for a Z-italic/sup 0/ mass of 93 GeV. We describe some unusual muon inclusive events.
TL;DR: In this paper, the mass matrix of the neutralinos order by order in m 1 2 /M W and m/MW was diagonalized analytically, and the decay of the next lightest neutralino was calculated by taking into account the mixing.
TL;DR: The electroweak form factors of baryons are studied in the semiclassical approximation to the Skyrme model and the dependence of the form factors on the momentum transfer is compared with phenomenological dipole parametrizations.
Abstract: The electroweak form factors of baryons are studied in the semiclassical approximation to the Skyrme model. General expressions for the form factors are given for arbitrary choices of the Skyrme-model Lagrangian. They are applied to the original two-parameter Skyrme model to compute the electric, magnetic, and axial-vector form factors of the nucleon and the electromagnetic nucleon-\ensuremath{\Delta} transition form factors. The dependence of the form factors on the momentum transfer is compared with phenomenological dipole parametrizations.
TL;DR: In this article, the phenomenological consequences of a dynamical scenario for electroweak symmetry breaking and generation of fermion masses, involving the presence of Fermions which transform under high colour representations, are presented.
TL;DR: In this paper, it was shown that even with fine tuning, it is impossible to obtain spontaneous CP violation in the minimal SU(2)L × SU (2)R × U(1)B−L model without getting unacceptable flavor-changing neutral currents.
TL;DR: In this paper, the SU(5) running opens up the parameter space of SU(2) × U(1) breaking solutions, and in particular all the values ߊ 0 | > 3 are allowed.
TL;DR: The phenomenological implications of supersymmetric and nonsupersymmetric E/sub 6/ theories, including the predictions for the proton lifetime, the electroweak mixing angle, and the couplings of all the fermions to the new Z boson are examined.
Abstract: We examine several patterns of breaking for supersymmetric and nonsupersymmetric E/sub 6/ theories that lead to an extra U(1) symmetry which at low energies (< or approx. =1 TeV) can reveal itself by the existence of an extra Z boson. We examine the phenomenological implications of such theories, including the predictions for the proton lifetime, the electroweak mixing angle, and the couplings of all the fermions to the new Z boson. In addition, we examine the constraints on the mass and width of the second Z from the present neutral-current and CERN pp-bar collider data. This analysis is especially relevant in light of recent results from superstring theories.
TL;DR: In this article, the authors summarized the accurate predictions of the standard AIP model and included both charged current and neutral current interactions as well as properties of the Z and W bosons.
Abstract: Some of the accurate predictions of the standard model are summarized. Included are both charged current and neutral current interactions as well as properties of the Z and W bosons. (AIP)