Showing papers on "Gauge boson published in 1999"
TL;DR: In this paper, the authors considered the Kaluza-Klein (KK) scenario where gravity propagates in the $(4+n)$-dimensional bulk of spacetime, while gauge and matter fields are confined to the $(3+1)$ -dimensional world volume of a brane configuration.
Abstract: We consider the novel Kaluza-Klein (KK) scenario where gravity propagates in the $(4+n)$-dimensional bulk of spacetime, while gauge and matter fields are confined to the $(3+1)$-dimensional world volume of a brane configuration. For simplicity we assume compactification of the extra n dimensions on a torus with a common scale $R,$ and identify the massive KK states in the four-dimensional spacetime. For a given KK level $\stackrel{\ensuremath{\rightarrow}}{n}$ there is one spin-2 state, $(n\ensuremath{-}1)$ spin-1 states, and $n(n\ensuremath{-}1)/2$ spin-0 states, all mass degenerate. We construct the effective interactions between these KK states and ordinary matter fields (fermions, gauge bosons, and scalars). We find that the spin-1 states decouple and that the spin-0 states only couple through the dilaton mode. We then derive the interacting Lagrangian for the KK states and standard model fields, and present the complete Feynman rules. We discuss some low-energy phenomenology for these new interactions for the case when $1/R$ is small compared to the electroweak scale, and the ultraviolet cutoff of the effective KK theory is on the order of 1 TeV.
692 citations
TL;DR: The phenomenological constraints on extra neutral gauge bosons at present and at future colliders are reviewed in this paper, where special attention is paid to the influence of radiative corrections, systematic errors, and kinematic cuts on the Z′ constraints.
439 citations
TL;DR: In this paper, the authors studied the cancellation of U(1) anomalies in Type I and Type IIB D = 4, N = 1 string vacua, and showed that for each given vacuum one has generically more than one U( 1) with non-vanishing triangle anomalies.
345 citations
TL;DR: In this article, the complete matrix elements for all final states were reduced to a few compact generic functions in the Electroweak Standard Model for polarized massless fermions. But their results are limited to the case where the fermion mass obeys all Ward identities.
338 citations
TL;DR: In this paper, the complete matrix elements for all final states are reduced to a few compact generic functions in the Electroweak Standard Model for polarized massless fermions. But their results are limited to the case where the fermion mass obeys all Ward identities.
Abstract: The complete matrix elements for e^+ e^- -> 4f and e^+ e^- -> 4f + gamma are calculated in the Electroweak Standard Model for polarized massless fermions. The matrix elements for all final states are reduced to a few compact generic functions. Monte Carlo generators for e^+ e^- -> 4f and e^+ e^- -> 4f + gamma are constructed. We compare different treatments of the finite widths of the electroweak gauge bosons; in particular, we include a scheme with a complex gauge-boson mass that obeys all Ward identities. The detailed discussion of numerical results comprises integrated cross sections as well as photon-energy distributions for all different final states.
331 citations
TL;DR: In this paper, a new method is discussed which vastly simplifies one of the two integrals over AdS d + 1 required to compute exchange graphs for four-point functions of scalars in the AdS/CFT correspondence.
232 citations
TL;DR: In this article, a new method is discussed which vastly simplifies one of the two integrals over AdS(d+1) required to compute exchange graphs for 4-point functions of scalars in the AdS/CFT correspondence.
Abstract: A new method is discussed which vastly simplifies one of the two integrals over AdS(d+1) required to compute exchange graphs for 4-point functions of scalars in the AdS/CFT correspondence. The explicit form of the bulk-to-bulk propagator is not required. Previous results for scalar, gauge boson and graviton exchange are reproduced, and new results are given for massive vectors. It is found that precisely for the cases that occur in the AdS(5) X S(5) compactification of Type IIB supergravity, the exchange diagrams reduce to a finite sum of graphs with quartic scalar vertices. The analogous integrals in n-point scalar diagrams for n>4 are also evaluated.
222 citations
TL;DR: In this paper, the authors proposed a new trigger for events with a high p[sub T] track and low hadronic activity, which can be triggered on when produced in association with jets.
Abstract: In supersymmetric models, W -inos, partners of the SU(2) gauge bosons, may be the lightest supersymmetric particles. For generic parameters, charged and neutral W -inos are highly degenerate. Charged W -inos travel macroscopic distances, but can decay to neutral W -inos and extremely soft leptons or pions before reaching the muon chambers, thereby circumventing conventional trigger requirements. However, these charginos are detectable, and can be triggered on when produced in association with jets. In addition, we propose a new trigger for events with a high p[sub T] track and low hadronic activity. For Tevatron RunthinspthinspII with luminosity 2 fb[sup [minus]1] , the proposed searches can discover W -inos with masses up to 300thinspthinspGeV and explore a substantial portion of the parameter space in sequestered sector models. [copyright] [ital 1999] [ital The American Physical Society ]
204 citations
TL;DR: In this paper, an upper bound for spontaneous muonium to antimuonium conversion was established at P-M (M over bar) less than or equal to 8.3 x 10(-11) (90% C.L.) in 0.1 T magnetic field, which implies consequences for speculative extensions to the standard model.
Abstract: A new upper limit for the probability of spontaneous muonium to antimuonium conversion was established at P-M (M over bar) less than or equal to 8.3 x 10(-11) (90% C.L.) in 0.1 T magnetic field, which implies consequences for speculative extensions to the standard model. Coupling parameters in R-parity-violating supersymmetry and the mass of a flavor diagonal bileptonic gauge boson can be significantly restricted. A Z(8) model with radiative mass generation through heavy lepton seed and the minimal version of 331 models are disfavored. [S0031-9007(98)08068-5].
190 citations
TL;DR: In this article, the authors used high-precision electroweak data to constrain the Higgs field in the presence of an extra dimension of size $R\ensuremath{\approx}{\mathrm{TeV}}^{\ensureMath{-}1}$.
Abstract: The presence of an extra dimension of size $R\ensuremath{\approx}{\mathrm{TeV}}^{\ensuremath{-}1}$ introduces a tower of Kaluza-Klein gauge boson excitations that affects the standard model relations between electroweak observables. The mixing of the W and Z bosons with their excitations changes their masses and couplings to fermions. This effect depends on the Higgs field, which may live in the bulk of the extra dimension, on its boundary, or may be a combination of both types of fields. We use high-precision electroweak data to constrain $1/R$. We find limits from 1 to 3 TeV from different observables, with a model-independent lower bound of 2.5 TeV.
141 citations
TL;DR: In this paper, the authors construct the gauge field and graviton propagators in Euclidean AdS(d+1) space-time by two different methods: the gauge invariant Maxwell or linearized Ricci operator is applied directly to bitensor ansatze for the propagators which reflect their gauge structure.
Abstract: We construct the gauge field and graviton propagators in Euclidean AdS(d+1) space-time by two different methods. In the first method the gauge invariant Maxwell or linearized Ricci operator is applied directly to bitensor ansatze for the propagators which reflect their gauge structure. This leads to a rapid determination of the physical part of the propagators in terms of elementary functions. The second method is a more traditional approach using covariant gauge fixing which leads to a solution for both physical and gauge parts of the propagators. The gauge invariant parts agree in both methods.
TL;DR: In this paper, the authors obtained the bounds on all the gauge invariant, flavour symmetric, CP-even operators of dimension 6 that can affect the electroweak precision tests.
TL;DR: In this paper, the authors studied how Kaluza-Klein excitations of the SM gauge bosons affect the electroweak precision observables in 4+1 dimensions, and they found the following 95% C.L. bounds: M>3.5 TeV and M>4.3 TeV if the higgs is so light that will be discovered at LEP2.
TL;DR: In this paper, the authors construct the gauge field and graviton propagators in Euclidean AdSd+1 space-time by two different methods: the gauge invariant Maxwell or linearized Ricci operator is applied directly to bitensor ansatze for the propagators which reflect their gauge structure.
TL;DR: In this paper, the scalar field exchange diagram for the correlation function of four scalar operators is evaluated in anti-de Sitter space, AdSd+1, where conformal dimensions δi, i = 1, 1, …, 4 of the operators and the dimension Δ of the exchanged field are arbitrary, constrained only to obey the unitarity bound.
TL;DR: In this paper, the magnetic properties of high T c cuprates from a gauge theory point of view, with emphasis on the underdoped regime, were analyzed in terms of a 1+1D U(1) gauge theory with massless Dirac fermions.
TL;DR: The direct production of Kaluza-Klein excitations of the photon and Z-boson at present and future colliders is studied in this paper. But this work is restricted to the LEPII, NLC and Tevatron colliders.
TL;DR: In this article, a method that allows the parton-shower algorithm to be augmented by higher-order information, thereby offering an economical route to a description of all event properties is presented.
TL;DR: In this article, indirect precision data is used to constrain the masses of possible extra Z′ bosons and their mixings with the ordinary Z. The lower mass limits are generally of the order of several hundred GeV and competitive with collider bounds.
TL;DR: The direct production of Kaluza-Klein excitations of the photon and Z-boson at present and future colliders is studied in this article, where the corresponding resonances can be produced and decay on-shell, triggering a characteristic pattern in the distribution of the dilepton invariant mass.
Abstract: The realization of low (TeV) scale strings usually requires the existence of large (TeV) extra dimensions where gauge bosons live. The direct production of Kaluza-Klein excitations of the photon and Z-boson at present and future colliders is studied in this work. At the LEPII, NLC and Tevatron colliders, these Kaluza-Klein modes lead to deviations from the standard model cross-sections, which provide lower bounds on their mass. At the LHC the corresponding resonances can be produced and decay on-shell, triggering a characteristic pattern in the distribution of the dilepton invariant mass.
TL;DR: In this paper, the mass of the lightest and second lightest CP even Higgs bosons in the (M+1)SSM, the MSSM extended by a gauge singlet, was studied.
Abstract: We study the upper limits on the mass of the lightest and second lightest CP even Higgs bosons in the (M+1)SSM, the MSSM extended by a gauge singlet. The dominant two loop contributions to the effective potential are included, which reduce the Higgs masses by 10 GeV. Since the coupling R of the lightest Higgs scalar to gauge bosons can be small, we study in detail the relations between the masses and couplings of both lightest scalars. We present upper bounds on the mass of a 'strongly' coupled Higgs (R > 1/2) as a function of lower experimental limits on the mass of a 'weakly' coupled Higgs (R < 1/2). With the help of these results, the whole parameter space of the model can be covered by Higgs boson searches.
TL;DR: In this article, a new production mechanism for neutralino cold dark matter in supersymmetric models with an extra UB−L(1) gauge symmetry was proposed, and it was shown that if the strings forming scale is less than about 108 GeV, the dark matter produced from strings can overclose the universe.
Abstract: Cosmic strings form in many extensions of the MSSM, in particular in models with an extra U(1) gauge symmetry. We propose a new production mechanism for neutralino cold dark matter in such models. We show that if the strings forming scale is less than about 108 GeV, the dark matter produced from strings can overclose the universe. The mass of the new U(1) gauge boson must be much larger than the Fermi scale which makes it unobservable in upcoming accelerator experiments. In supersymmetric models with an extra UB−L(1) gauge symmetry, the requirement of Ω ≤ 1 puts an upper bound on the neutrino mass of about 30 eV provided neutrino masses are generated by the see-saw mechanism.
TL;DR: In this paper, the amplitude for exchange of massless gauge bosons between pairs of massive scalar fields in anti-de Sitter space was studied and a concise, covariant, Y2K compatible derivation of the gauge boson propagator in AdS d + 1 was given.
TL;DR: In this article, the effects of new effective interactions on Higgs-boson phenomenology were reviewed using a linearly realized SU(2)L×U(1)Y invariant effective Lagrangian.
Abstract: We review the effects of new effective interactions on Higgs-boson phenomenology. New physics in the electroweak bosonic sector is expected to induce additional interactions between the Higgs doublet field and the electroweak gauge bosons, leading to anomalous Higgs couplings as well as anomalous gauge-boson self-interactions. Using a linearly realized SU(2)L×U(1)Y invariant effective Lagrangian to describe the bosonic sector of the Standard Model, we review the effects of the new effective interactions on the Higgs-boson production rates and decay modes. We summarize the results from searches for the new Higgs signatures induced by the anomalous interactions in order to constrain the scale of new physics, in particular at CERN LEP and Fermilab Tevatron colliders.
TL;DR: In this article, the one-loop non-holomorphic effective potential for the N = 4 SU (n ) supersymmetric Yang-Mills theory with the gauge symmetry broken down to the maximal torus U (1) n −1.
01 Jan 1999
TL;DR: In this article, the authors present a self-contained treatment of planar gauge theories broken down to some finite residual gauge group H via the Higgs mechanism, and the main focus is on the discrete H gauge theory describing the long-distance physics of such a model.
Abstract: We present a self-contained treatment of planar gauge theories broken down to some finite residual gauge group H via the Higgs mechanism. The main focus is on the discrete H gauge theory describing the long-distance physics of such a model. The spectrum features global H charges, magnetic vortices, and dyonic combinations. Due to the AharonovBohm effect, these particles exhibit topological interactions. Among other things, we review the Hopf algebra related to this discrete H gauge theory, which provides a unified description of the spin, braid, and fusion properties of the particles in this model. Exotic phenomena such as flux metamorphosis, Alice fluxes, Cheshire charge, (non-)Abelian braid statistics, the generalized spin-statistics connection, and non-Abelian AharonovBohm scattering are explained and illustrated by representative examples.
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.
Abstract: We consider the possibility of gauge bosons living in the recently proposed five-dimensional theory with localized gravity. We study the mass spectrum of the Kaluza-Klein (KK) excitations of the gauge fields and calculate their couplings to the boundaries of the fifth dimension. We find a different behaviour from the case of the graviton. In particular, we find that the massless mode is not localized in the extra dimension and that the KK excitations have sizeable couplings to the two boundaries. We also discuss possible phenomenological implications for the case of the standard model gauge bosons.
TL;DR: In this paper, the decays of Higgs bosons to a lighter Higgs and a virtual gauge boson in the context of the non-supersymmetric two-Higgs doublet model (2HDM) were studied.
TL;DR: In this paper, the renormalization of the fermion mixing matrix in the Standard Model was studied and the constraints that must be satisfied to respect gauge invariance to all orders were derived.
TL;DR: In this article, a recent construction of the electroweak theory, based on perturbative quantum gauge invariance alone, is extended to the case of more generations of fermions with arbitrary mixing.
Abstract: A recent construction of the electroweak theory, based on perturbative quantum gauge invariance alone, is extended to the case of more generations of fermions with arbitrary mixing. The conditions implied by second order gauge invariance lead to an isolated solution for the ferm- ionic couplings in agreement with the standard model. Third order gauge invariance determines the Higgs potential. The resulting massive gauge theory is manifestly gauge invariant, after con- struction.