Showing papers on "Gauge boson published in 2000"
TL;DR: The Particle Data Group's biennial review as mentioned in this paper summarizes much of Particle Physics, using data from previous editions, plus 1600 new measurements from 550 papers, and lists, evaluates and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons.
Abstract: This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 1600 new measurements from 550 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http: //pdg. lbl. gov.
2,263 citations
TL;DR: In this paper, it is shown that it is not necessary to confine the standard model fields on the brane and analyze the possibility of having the fields actually living in the slice of AdS.
1,079 citations
CERN1
TL;DR: In this article, the mass spectrum of the Kaluza-Klein (KK) excitations of the gauge fields and their couplings to the boundaries of the fifth dimension were studied.
377 citations
TL;DR: In this article, the standard model (SM) is placed on the brane to solve the gauge hierarchy problem in five-dimensional anti-char21{}de Sitter spacetime.
Abstract: We discuss issues in an attempt to put the standard model (SM) in five-dimensional anti\char21{}de Sitter spacetime compactified on ${S}^{1}{/Z}_{2}.$ The recently proposed approach to the gauge hierarchy problem by using this background geometry, with the SM confined on a boundary, is extended to a situation where (some of) the SM particles reside in the five-dimensional bulk. In particular, we find a localization of zero modes of bulk fermions near the boundary with a negative tension. Unlike the compactification with the flat metric, these fermion zero modes couple to Kaluza-Klein (KK) excitations of the SM gauge bosons. Interestingly, only low-lying modes of such KK gauge bosons have non-negligible couplings. Current electroweak precision data give a constraint that the first KK mode be heavier than $9$ TeV. We also argue that at least the Higgs field should be confined on the brane to utilize the Randall-Sundrum background as a solution to the gauge hierarchy.
340 citations
199 citations
TL;DR: In this article, the authors derive nonperturbative classical solutions of noncommutative U(1) gauge theory with or without Higgs field, representing static magnetic flux tubes with arbitrary cross-section.
182 citations
TL;DR: In this article, the infrared evolution equation was used to obtain double logarithmic asymptotics of scattering amplitudes and discussed how it can be applied, in the case of broken gauge symmetry, to the standard model of electroweak processes.
Abstract: At future linear ${e}^{+}{e}^{\ensuremath{-}}$ collider experiments in the TeV range, Sudakov double logarithms originating from massive boson exchange can lead to significant corrections to the cross sections of the observable processes. These effects are important for the high precision objectives of the Next Linear Collider. We use the infrared evolution equation, based on a gauge invariant dispersive method, to obtain double logarithmic asymptotics of scattering amplitudes and discuss how it can be applied, in the case of broken gauge symmetry, to the standard model of electroweak processes. We discuss the double logarithmic effects to both non-radiative processes and to processes accompanied by soft gauge boson emission. In all cases the Sudakov double logarithms are found to exponentiate. We also discuss double logarithmic effects of a non-Sudakov type which appear in Regge-like processes.
172 citations
TL;DR: In this paper, one-loop corrections to the mass matrix of the neutral Higgs bosons of the Minimal Supersymmetric Standard Model with explicit CP violation are presented. But they do not take into account the running quark masses.
148 citations
TL;DR: In this article, the authors discuss the behavior of DKP field and its physical components under gauge transformations and show that these problems simply do not exist if one correctly analyses the physical components of the field.
143 citations
TL;DR: In this article, it is shown that it is not necessary to confine the standard model fields on the brane and analyze the possibility of having the fields actually living in the slice of AdS.
Abstract: Five-dimensional models where the bulk is a slice of AdS have the virtue of solving the hierarchy problem. The electroweak scale is generated by a ``warp'' factor of the induced metric on the brane where the standard model fields live. However, it is not necessary to confine the standard model fields on the brane and we analyze the possibility of having the fields actually living in the slice of AdS. Specifically, we study the behaviour of fermions, gauge bosons and scalars in this geometry and their implications on electroweak physics. These scenarios can provide an explanation of the fermion mass hierarchy by warp factors. We also consider the case of supersymmetry in the bulk, and analyze the conditions on the mass spectrum. Finally, a model is proposed where the warp factor generates a small (TeV) supersymmetry-breaking scale, with the gauge interactions mediating the breaking to the scalar sector.
135 citations
TL;DR: In this paper, a pedagogical introduction into noncommutative gauge theories, their stringy origin, and nonperturbative effects, including monopole and instanton solutions, is presented.
Abstract: We present a pedagogical introduction into noncommutative gauge theories, their stringy origin, and non-perturbative effects, including monopole and instanton solutions
TL;DR: An excellent fit to the data is obtained, suggestive of a family nonuniversal Z' similar to those predicted in a class of superstring theories.
Abstract: A new analysis of the hadronic peak cross section at LEP 1 implies a small amount of missing invisible width in $Z$ decays, while the effective weak charge in atomic parity violation has been determined recently to $0.6%$ accuracy, indicating a significantly negative $S$ parameter. As a consequence, the data are described well if the presence of an extra ${Z}^{\ensuremath{'}}$ boson, such as predicted in grand unified theories, is assumed. Moreover, the data are now rich enough to study an arbitrary extra ${Z}^{\ensuremath{'}}$ boson and to determine its couplings in a model independent way. An excellent fit to the data is obtained in this case, suggestive of a family nonuniversal ${Z}^{\ensuremath{'}}$ similar to those predicted in a class of superstring theories.
TL;DR: In this article, the authors investigate the main experimental signatures of these possibilities, related to the production of Kaluza-Klein excitations of gluons and electroweak gauge bosons.
TL;DR: In this paper, it was shown that the most tightly bound scalar is a composite of top quarks, having the quantum numbers of the Higgs doublet and a large coupling to the top quark.
Abstract: If the gauge fields of the standard model propagate in TeV-size extra dimensions, they rapidly become strongly coupled and can form scalar bound states of quarks and leptons. If the quarks and leptons of the third generation propagate in 6 or 8 dimensions, we argue that the most tightly bound scalar is a composite of top quarks, having the quantum numbers of the Higgs doublet and a large coupling to the top quark. In the case where the gauge bosons propagate in a bulk of a certain volume, this composite Higgs doublet can successfully trigger electroweak symmetry breaking. The mass of the top quark is correctly predicted to within 20%, without the need to add a fundamental Yukawa interaction, and the Higgs boson mass is predicted to lie in the range 165--230 GeV. In addition to the Higgs boson, there may be a few other scalar composites sufficiently light to be observed at upcoming collider experiments.
16 Jun 2000
TL;DR: Marolf and Donald as mentioned in this paper defined three notions of either electric or magnetic charge associated with a given gauge field and introduced a language for discussing these charges and the properties of each charge are described.
Abstract: Author(s): Marolf, Donald | Abstract: In theories with Chern-Simons terms or modified Bianchi identities, it is useful to define three notions of either electric or magnetic charge associated with a given gauge field. A language for discussing these charges is introduced and the properties of each charge are described. `Brane source charge' is gauge invariant and localized but not conserved or quantized, `Maxwell charge' is gauge invariant and conserved but not localized or quantized, while `Page charge' conserved, localized, and quantized but not gauge invariant. This provides a further perspective on the issue of charge quantization recently raised by Bachas, Douglas, and Schweigert.
TL;DR: A new mechanism for formation of topological defects in a U(1) model with a local gauge symmetry is proposed, which leads to definite predictions, which are qualitatively different from those of the Kibble-Zurek mechanism of global theories.
Abstract: We propose a new mechanism for formation of topological defects in a U(1) model with a local gauge symmetry. This mechanism leads to definite predictions, which are qualitatively different from those of the Kibble-Zurek mechanism of global theories. We confirm these predictions in numerical simulations, and they can also be tested in superconductor experiments. We believe that the mechanism generalizes to more complicated theories.
TL;DR: In this article, the Coulomb and Higgs branches of 3D gauge theories with = 2 supersymmetry were studied, and it was shown that Coulomb branches of such theories may be rendered compact by the dynamical generation of Chern-Simons terms.
Abstract: We study three dimensional gauge theories with = 2 supersymmetry. We show that the Coulomb branches of such theories may be rendered compact by the dynamical generation of Chern-Simons terms and present a new class of mirror symmetric theories in which both Coulomb and Higgs branches have a natural description in terms of toric geometry.
TL;DR: In this paper, the authors studied the discovery potential of the CERN LHC, Fermilab Tevatron and Cern LEP colliders in the search for the neutral CP-even Higgs boson of the MSSM.
Abstract: We study the discovery potential of the CERN LHC, Fermilab Tevatron and CERN LEP colliders in the search for the neutral CP-even Higgs boson of the MSSM which couples to the weak gauge bosons with a strength close to the standard model one and, hence, plays a relevant role in the mechanism of electroweak symmetry breaking. We place special emphasis on the radiative effects which influence the discovery reach of these colliders. We concentrate on the Vbb(bar sign) channel, with V=Z or W, and on the channels with diphoton final states, which are the dominant ones for the search for a light standard model Higgs boson at LEP or Tevatron and LHC, respectively. By analyzing the parameters of the MSSM for which the searches become difficult at one or more of these three colliders, we demonstrate their complementarity in the search for a light Higgs boson which plays a relevant role in the mechanism of electroweak symmetry breaking. (c) 2000 The American Physical Society.
TL;DR: In this paper, the authors consider a Randall-Sundrum model in which the Standard Model fermions and gauge bosons correspond to bulk fields and show how the observed charged fermion masses and CKM mixings can be explained, without introducing hierarchical Yukawa couplings.
Abstract: We consider a Randall-Sundrum model in which the Standard Model fermions and gauge bosons correspond to bulk fields. We show how the observed charged fermion masses and CKM mixings can be explained, without introducing hierarchical Yukawa couplings. We then study the impact on the mass scales associated with non-renormalizable operators responsible for proton decay, neutrino masses, and flavor changing neutral currents. Although mass scales as high as 10^{11}- 10^{12} GeV are in principle possible, dimensionless couplings of order 10^{-8} are still needed to adequately suppress proton decay. Large neutrino mixings seem to require new physics beyond the Standard Model.
TL;DR: In this paper, the Sudakov double logarithmic corrections to the form factor of fermion in the SU (2)⊗ U (1) electroweak theory were investigated.
TL;DR: In this paper, a non-Abelian vacuum gauge field is projected onto a fixed (electromagnetic) direction in isospace, with nonvanishing magnetic helicity, which coincides with the winding number of U.S. atoms.
Abstract: Projecting a non-Abelian $\mathrm{SU}(2)$ vacuum gauge field---a pure gauge constructed from the group element $U$---onto a fixed (electromagnetic) direction in isospace gives rise to a nontrivial magnetic field, with nonvanishing magnetic helicity, which coincides with the winding number of U. Although the helicity is not conserved under Maxwell (vacuum) evolution, it retains one-half its initial value at infinite time.
TL;DR: In this article, a supersymmetric nonlinear sigma model is obtained from linear sigma models by imposing super-symmetric constraints, which can be expressed by D-terms and F-terms depending on the target manifolds.
Abstract: Supersymmetric nonlinear sigma models are obtained from linear sigma models by imposing supersymmetric constraints. If we introduce auxiliary chiral and vector superfields, these constraints can be expressed by D-terms and F-terms depending on the target manifolds. Auxiliary vector superfields appear as gauge fields without kinetic terms. If there are no D-term constraints, the target manifolds are always non-compact manifolds. When all the degrees of freedom in these non-compact directions are eliminated by gauge symmetries, the target manifold becomes compact. All supersymmetric nonlinear sigma models, whose target manifolds are the hermitian symmetric spaces, are successfully formulated as gauge theories.
TL;DR: In this article, the authors present analytical results for the leading contributions of the top quark to the electroweak rho parameter at order GF^3 Mt^6 and GF^2 Mt^4 alpha_s.
Abstract: We present analytical results for the leading contributions of the top quark to the electroweak rho parameter at order GF^3 Mt^6 and GF^2 Mt^4 alpha_s. The Higgs boson and the gauge bosons are taken to be massless in this limit. The correction of order GF^3 Mt^6 is found to be sizeable in comparison to the the leading two-loop GF^2 Mt^4 correction, however it is much smaller than the subleading GF^2 Mt^2 MZ^2 correction.
TL;DR: In this article, the effects of the mixing between the short-distance and the long-distance degrees of freedom characteristic of non-commutative field theories were studied and it was shown that such mixing violates the universality of the Wilsonian action and leads to IR singularities.
Abstract: Using background field perturbation theory we study Wilsonian effective actions of noncommutative gauge theories with an arbitrary matter content. We determine the Wilsonian coupling constant and the gauge boson polarization tensor as functions of the momentum scale k at the one-loop level and study their short-distance behaviour as theta k ->0, where theta is the noncommutativity parameter. The mixing between the short-distance and the long-distance degrees of freedom characteristic of noncommutative field theories violates the universality of the Wilsonian action and leads to IR-singularities. We find, in agreement with known results, that the quadratic IR divergencies cancel in supersymmetric gauge theories. The logarithmic divergencies disappear in mass-deformed N=4 theories, but not in other finite N=2 theories. We next concentrate on finite N=2 and mass-deformed N=4 supersymmetric U(1) gauge theories with massive hypermultiplets. The Wilsonian running coupling exhibits a non-trivial threshold behaviour at and well below the noncomutativity scale, eventually becoming flat in the extreme infrared in N=4 theories, but not in N=2 theories. This is interpreted as the (non)-existence of a non-singular commutative limit where the theory is described by a commutative N=2 pure U(1) theory. We expect that our analysis of finite theories is exact to all orders in perturbation theory.
TL;DR: In this article, a detailed analysis of production at the upgraded Fermilab Tevatron and the CERN Large Hadron Collider is presented for general $\mathrm{ZZZ}$ and ''ensuremath{\gamma}$ couplings.
Abstract: A detailed analysis of $\mathrm{ZZ}$ production at the upgraded Fermilab Tevatron and the CERN Large Hadron Collider is presented for general $\mathrm{ZZZ}$ and $\mathrm{ZZ}\ensuremath{\gamma}$ couplings. Deviations from the standard model gauge theory structure for each of these can be parametrized in terms of two form factors which are severely restricted by unitarity at high energy. Achievable limits on these couplings are shown to be a dramatic improvement over the limits currently obtained by ${e}^{+}{e}^{\ensuremath{-}}$ experiments.
TL;DR: In this paper, the authors examine the Standard and the New Physics contributions to the ZZZ, ZZγ and Zγγ neutral gauge couplings, and compare quantitative estimates from SM, MSSM and some specific examples of NP contributions.
Abstract: We examine the Standard and the New Physics (NP) contributions to the ZZZ, ZZγ and Zγγ neutral gauge couplings. At the one-loop level, if we assume that there is no CP violation contained in NP beyond the Standard Model one, we find that only CP conserving neutral gauge couplings are generated, either from the standard quarks and leptons, or from possible New Physics (NP) fermions. Bosonic one-loop diagrams never contribute to these couplings, while the aforementioned fermionic contributions satisfy h Z ≃ −f 5 , h Z = h 4 = 0. We also study examples of two-loop NP effects that could generate non vanishing h ,Z couplings. We compare quantitative estimates from SM, MSSM and some specific examples of NP contributions, and we discuss their observability at future colliders.
TL;DR: In this paper, the authors investigated the contribution of non-planar diagrams to the non-commutative super Yang-Mills (SYM) action in a momentum expansion and found that the contributions from nonplanar diagram in general involve additional structure beyond the usual *-product, arising from the nontrivial worldsheet correlations surviving the field theory limit.
Abstract: We investigate N=4 noncommutative super Yang-Mills (SYM) theory. We compute the one-loop four gauge boson scattering amplitude on parallel Dp-branes, and find the corresponding contribution to the noncommutative SYM one-loop action in a momentum expansion. The result is somewhat surprising. We find that while the planar diagram can be written using the usual *-product, the contributions from nonplanar diagrams in general involve additional structure beyond the *-product, arising from the nontrivial worldsheet correlations surviving the field theory limit. To each nonplanar diagram, depending on the number n of external vertex operator insertions on each boundary, there is a corresponding *_n n-ary operation. We further find that it is no longer possible to write down an off-shell gauge invariant one-loop effective action using the noncommutative field strength defined at tree-level.
TL;DR: In this article, the authors investigated the pattern of CP violation in K0-K 0, B0d-B 0 d and B0s−B 0 s mixing in a symmetrical SU (2)L×SU(2)R×U(1) model with spontaneous CP violation.
TL;DR: In this article, the mass spectrum of the SU(2) adjoint Higgs model in 2+1 dimensions at several points located in the (metastable) confinement region of its phase diagram is computed.
TL;DR: In this article, the decoupling theorem for heavy Higgs particles in the MSSM was shown to hold for all the non-standard particles, namely, squarks, sleptons, charginos, neutralinos, and the heavy higgs particles, in the so-called decoupled limit.
Abstract: We study the heavy Higgs sector of the MSSM composed of the H ± , H 0 and A 0 particles in the so-called decoupling limit where mA0 ≫ mZ. By integrating out these heavy Higgs particles to one-loop, we compute the effective action for the electroweak gauge bosons and find out that, in the decoupling limit, all the heavy Higgs effects can be absorbed into redefinitions of the Standard Model electroweak parameters. This demonstrates explicitely that the decoupling theorem works for the heavy MSSM Higgs particles. This is also compared with the paradigmatic and different case of the Standard Model heavy Higgs particle. Finally, this work together with our two previous works, complete the demonstration that all the non-standard particles in the MSSM, namely, squarks, sleptons, charginos, neutralinos and the heavy Higgs particles, decouple to one-loop from the low energy electroweak gauge boson physics.