Showing papers on "Gauge boson published in 1991"
TL;DR: In this paper, it was shown that a radiative correction of the top and stop loops gives a finite, but non-negligible contribution to Higgs scalar masses if m, "'" 150-250 GeV.
Abstract: In the minimal supersymmetric standard madel, it is shown that a radiative correction of the top and stop loops gives a finite, but non-negligible contribution to Higgs scalar masses if m, "'" 150-250 GeV. The upper limit to the lightest-scalar mass becomes 70-190 GeV in the range of heavy top quark. 1 The mechanism of electroweak symmetry breaking is one of the most important issues in the present particle physics_ In the standard electroweak model a funda mental Higgs doublet is introduceq to cause the spontaneous symmetry breaking. Supersymmetry (SUSY), eliminating all quadratic divergences, may provide a better theoretical basis to describe a fundamental Higgs boson with a relatively small mass to a high energy cutoff scale, say the Planck scale for example. I) In the minimal SUSY extension of the standard electroweak model the Higgs sector consists of two chiral superfields of Higgs doublets (/JHl and (/JH2 with opposite hypercharges. They are required to give masses for all quarks and leptons and to guarantee the ~bsence of the gauge anomaly. Five physical Higgs bosons among them survive the gauge symmetry breaking, namely, there appear two neutral scalars rpa and rpb, a neutral pseudoscalar X and a pair of charged scalars x± as physical particles. It has been, furthermore, shown by many authors 2 ) that there is at least one neutral scalar boson lighter than ZO(m
699 citations
TL;DR: In this paper, the physical consequences of kinetic mixing terms for the different U (1) gauge fields in the lagrangian were studied and it was shown that electromagnetic interactions are not affected by these mixing terms.
214 citations
TL;DR: In this article, an effective lagrangian based framework for the inclusion of new heavy physics effects on gauge boson self-energies was developed, where various observables may be expressed in terms of the parameters S, T and U.
142 citations
TL;DR: A resummation method for the complete calculation of the effects of screening to leading order in the coupling constant is developed and is applied to calculte the rate of energy loss of a hot plasma from the Primakoff production of axions.
Abstract: Tree-level calculations of thermal processes involving the exchange of massless gauge bosons give rise to infrared divergences which are screened by thermal loop corrections. For gauge theories at high temperatures or densities, a resummation method for the complete calculation of the effects of screening to leading order in the coupling constant is developed. The method is applied to calculte the rate of energy loss of a hot plasma from the Primakoff production of axions. Previous {ital ad} {ital hoc} prescriptions for screening significantly underestimate the contribution from magnetic scattering.
120 citations
TL;DR: In this article, it was shown that the parital wave unitarity is not respected by the tree diagrams for two-body scattering of gauge bosons, and the weak interactions must become strong at high energies.
Abstract: We give an $S$-matrix-theoretic demonstration that if the Higgs-boson mass exceeds ${M}_{c}={(8\ensuremath{\pi}\frac{\sqrt{2}}{3}{G}_{F})}^{\frac{1}{2}}$, parital-wave unitarity is not respected by the tree diagrams for two-body scattering of gauge bosons, and the weak interactions must become strong at high energies. We exhibit the relation of this bound to the structure of the Higgs-Goldstone Lagrangian, and speculate on the consequences of strongly coupled Higgs-Goldstone systems. Prospects for the observation of massive Higgs scalars are noted.
118 citations
TL;DR: A physical definition of the Z-boson mass was proposed in this article, which is field-redefinition invariant and gauge invariant to all orders and lies approximately 26 MeV below the commonly used on-shell mass.
114 citations
TL;DR: In this article, the authors derived a general set of identities that determine the gauge dependence of the effective action and all associated n-point vertex functions in a wide class of gauge theories and used them to resolve the recent controversy concerning the dispersion relations in high-temperature QCD and quantum gravity.
110 citations
TL;DR: It is demonstrated that the fine-tuning required to keep one-loop corrections to {rho} and the Higgs-boson couplings small is similar in nature to that required in the SM to keep the SM Higgs -boson mass in themore » perturbative regime.
Abstract: Extensions of the Higgs sector of the standard model (SM) that employ only doublet and singlet Higgs-field representations are not the only ones that guarantee \ensuremath{\rho}=1 at the tree level. Higgs sectors containing triplet (and higher) representations can be constructed in such a way that there is a tree-level custodial SU(2) symmetry yielding \ensuremath{\rho}=1. However, this custodial SU(2) is inevitably violated at the one-loop level. We explore the implications of this violation in the context of a Higgs sector containing triplet fields. In particular, we show that it leads to one-loop corrections to \ensuremath{\rho} and to certain mixings among the Higgs bosons and gauge bosons of the model that are quadratically divergent, thereby creating a new naturalness problem for \ensuremath{\rho} and for certain Higgs-boson couplings. This new class of naturalness problems first arises for a Higgs sector with triplet representations, making such a sector an interesting case study. A priori, deviations from \ensuremath{\rho}=1 induced at one loop are of arbitrary magnitude and sign. We demonstrate that the fine-tuning required to keep one-loop corrections to \ensuremath{\rho} and the Higgs-boson couplings small is similar in nature to that required in the SM to keep the SM Higgs-boson mass in the perturbative regime.
105 citations
CERN1
TL;DR: In this article, the instanton-induced contribution to the total cross section of vector boson scattering in SU (2) gauge theory with and without Higgs mechanism was investigated.
93 citations
TL;DR: In this paper, the authors study possible ways of unraveling a CP non-invariant Higgs sector through the interactions of Higgs bosons with gauge bosons and derive some general sum rules for the couplings.
76 citations
TL;DR: In this article, the authors investigated the bosonic zero modes of cosmic strings formed in the breaking of a gauge group G → H, and found exact charge-carrying zero mode solutions.
TL;DR: The need for additional higher order gauge dependent terms in the conventional mass renormalization of Z 0 (and by extension other unstable particles), deduced recently from a theoretical argument involving gauge invariance, is rederived by calculations of specific physical amplitudes, thus providing an independent proof as mentioned in this paper.
TL;DR: In this article, the authors give limits on the most relevant CP-odd signets, sometimes directly from experiment, often via observable effects induced by electroweak and QCD quantum corrections.
TL;DR: In this paper, the evolution of nonlinear perturbations of the regular Bartnik-McKinnon solution of the SU(2) Einstein-Yang-Mills equations is studied numerically.
TL;DR: In this article, the potentialities for exposing physics beyond the standard model that are offered by accurate measurements of the process Z → bb in a high luminosity phase at LEP were investigated.
Book•
01 Jan 1991
TL;DR: In this article, the authors present a model for quantization of local field theories in the context of quantum chromodynamics, based on Yang-Mills Fields and the Higgs Mechanism.
Abstract: QUANTUM FIELD THEORY. Relativistic Wave Equations. Canonical Quantization of Local Field Theories. Perturbation Theory and Evaluation of the S-Matrix. Path Integral Quantization. GAUGE FIELD THEORIES. Symmetry and Group Theory. Weak and Electromagnetic Interactions. Yang-Mills Fields. Spontaneously Broken Symmetry and the Higgs Mechanism. Standard Electroweak Model. The Strong Interactions and Quantum Chromodynamics. Grand Unified Theories. MODELS AND APPLICATIONS. Models for QCD. Non-Perturbative Methods in Gauge Field Theories. Deconfined Quarks and Gluons. Cosmology and Gauge Theories. Appendices. References. Index.
TL;DR: In this article, the authors considered relativistic Chern-Simons Higgs theories with arbitrary local gauge group and matter representation and showed that the self-duality equations in unitary gauge are identical to those in the abelian theory, which implies the existence of solitons in both the symmetric and asymmetric phases.
TL;DR: In this article, the scale and effects of a new neutral gauge boson, Z', in the standard model Z depend only on MZ and MW, and the effect of mixing angles of Z-Z' mixing on the width of the Z and its effect on primordial nucleosynthesis calculations is investigated.
Abstract: We discuss the scale and effects of a new neutral gauge boson, Z', in our recently derived superstring standard-like model, which is a combination of B - L and T3R and provides a mechanism to suppress proton decay. We show that the mass and mixing angle of the Z' with the standard model Z depend only on MZ and MW. For the central values of MZ and MW from recent experiments, MZ'~1000 GeV. We discuss the effect of Z-Z' mixing on the width of the Z and investigate the effect on primordial nucleosynthesis calculations, from which we find that the existence of light right-handed neutrinos with a Z' is excluded unless MZ'≥1.5 TeV.
TL;DR: In this article, the authors investigated the vacuum structure of the pure SU (3) gauge theory in the maximally abelian gauge and found that monopoles condense in the confined phase of the vacuum, in accordance with the pivture of a dual superconductor.
TL;DR: In this paper, the expected leading corrections to the three gauge boson vertices from loop effects in the symmetry breaking sector were analyzed using a chiral lagrangian framework, and it was shown that these particular corrections have not been included in previous chiral-lagrangian-based analyses of hadron colliders.
TL;DR: In this article, the authors developed a technique for calculating interference effects in the effective-W boson method and found that these effects produce a very large azimuthal asymmetry for single Higgs boson production.
Abstract: We develop the technique for calculating interference effects in the effective-W boson method. We find that these effects produce a very large azimuthal asymmetry for single Higgs boson production, which could be used as identification of the process. We also find that the cross section of Higgs boson pair production strongly depends on Higgs self-interaction, and for non-standard models of Higgs bosons could be 5 or 10 times larger than in the case of the standard one.
TL;DR: In this article, the density ϱ of monopoles in SU(2) gauge theory was investigated, and it was shown that ϱ is a physical quantity, and that below a certain critical volume the monopole density rapidly decreases.
TL;DR: In this paper, a simple phenomenological model is applied to describe the scattering amplitudes of strongly interacting longitudinal gauge bosons at the future colliders, LHC and SSC, based on the use of the well-known techniques from chiral effective Lagrangians and chiral perturbation theory.
Abstract: In this paper we apply a simple phenomenological model to describe the scattering amplitudes of strongly interacting longitudinal gauge bosons at the futurepp colliders, LHC and SSC The model is based on the use of the well-known techniques from chiral effective Lagrangians and chiral perturbation theory, supplemented by a unitarization method for the scattering amplitudes The generality of the approach allows one to deal with various physical situations in the unknown symmetry breaking sector of the Standard Model In particular we mimic the two typical scenarios for the symmetry breaking sector: one of Higgs-type and the other of QCD-type Two different unitarization methods have been implemented for comparison: the Pade approximants method and theK-matrix method The first one permits the incorporation of the possibility of dynamical resonances as it can develop poles for the various different (I, J)-channels A systematic study of strongly interacting signals for both LHC and SSC is presented, and their rates and efficiencies are compared
TL;DR: In this paper, the authors studied the phenomenological implications of the model for Z0 decays, including the rates for single chargino production in Z0→ξ±τ±, as well as for the so-called Zen events, and found that they may be measurable at LEP.
TL;DR: In this article, the problem of two-particle scattering in Witten's Chern-Simons gauge theory of (2 + 1)-dimensional gravity was discussed and the Poincare theory was recovered by projection.
01 Oct 1991
TL;DR: In this article, A.A. Ali and G.Qadir have discussed the ten fateful years in particle physics from the quark model to the standard model, M.M. Mohapatra revitalizing grand unification, Q. Shafi polarized inclusive scattering from high-spin targets.
Abstract: Foreword, A. Salam using quark and lepton masses to guess the scalar spectrum, S. Weinberg fermion masses in the standard model, I.H. Lee and S.D. Drell wave packet tunnelling and the Buttiker precession time, F.E. Low and P.F. Mende delta-function potentials in two and three-dimensional quantum mechanics, R. Jackiw emergence of spinor from flux and lattice hopping, A. Zee atomic physics constraints on the existence of ultralight, ultraweak gauge bosons, G. Feinberg and J. Sucher theories with signal-locality and their experimental tests, V. Singh and S.M. Roy higher order contributions to delta r, S. Fanchiotti and A. Sirlin symmetry in strings and particle physics, L. Dolan flavour and spin content of the proton, Riazuddin and Fayyazuddin origin of masses in the standard model, R.N. Mohapatra revitalizing grand unification, Q. Shafi polarized inclusive scattering from high-spin targets, P. Hoodbhoy constraints in dynamical symmetry breaking mechanism from elecroweak data, A. Ali and G. Degrassi from the quark model to the standard model - ten fateful years in particle physics, M.A.B. Beg dynamical isospin symmetry breaking and seesaw mechanism in extended technicolour, A. Hernandex-Galeana and A. Zepeda random matrix formulation of the fractional quantum hall effect, D.J.E. Callaway the gravitational force in general relativity, A. Qadir.
TL;DR: In this article, the LEP results from last year's run are shown to imply a considerable improvement in the bounds on the possible admixture of a new non-standard neutral gauge boson in the observed Z state.
TL;DR: In this paper, the authors discuss the possibility of spontaneous parity violation in three-dimensional minkowskian and euclidean gauge theories with scalar fields and show that parity can be broken spontaneously only in the phase with restored gauge invariance, but is unbroken if the scalars have vacuum expectation values.
TL;DR: In this paper, a mechanism to generate attractive scalar four-fermion interactions by the gauge principle is introduced, and various cases of extended electroweak gauge groups are shown to produce specific mass hierarchies in weak doublets.
TL;DR: In this article, an analysis of the laboratory constraints on the parameters of an additional neutral gauge boson from the E 6 gauge group is presented, where the mass and mixing of the Z′ are given for the general unconstrained E 6 model as well as for the case of constrained string models.