Decay properties of a class of doubly charged Higgs bosons

We study the leptonic decays of a doubly charged Higgs bosons class which is predicted by a model based on the SU_(3)C⊗SU_(2)L⊗U_(1)N$\mathrm{SU}{(3)}_C\otimes \mathrm{SU}{(2)}_L\otimes \mathrm{U}{(1)}_N$ electroweak gauge symmetry. In contrast to other models, decays into τ^±τ^±${\tau }^{\pm }{\tau }^{\pm }$ are largely dominant (99.5% or more). Coupling of these scalars to two standard charged gauge bosons are either zero or very suppressed. Couplings to two different flavor of charged leptons do not occur. Some coupling features imposed by symmetry and representation content lead to simple relationships between decay rates and doubly charged Higgs masses. Some of the parameters depend only on the decay widths and on the charged lepton masses. In order to clarify the relevance of our results, some aspects of this model are compared with the Higgs triplet model.     

Associated production of Higgs bosons with Z bosons by charged leptons in strong external fields

The probabilities of the associated production of a Higgs boson with a Z boson by a charged lepton in the field of a plane electromagnetic wave of arbitrary intensity and in a constant crossed field are obtained. The behavior of the cross section of the process as a function of the particle energies and the external field intensity is investigated for various values of the Higgs boson mass. It is shown that there is a logarithmic increase in the photoproduction cross section at superhigh energies up to a value significantly exceeding the cross section of the reaction e ⁺+e ⁻→Z+H, which is presently regarded as the most probable channel for the production of Higgs bosons. Zh. éksp. Teor. Fiz. 113, 1979–1990 (June 1998)     

Landau-Yang theorem and decays of a Z' boson into two Z bosons

We study the decay of a Z' boson into two Z bosons by extending the Landau-Yang theorem to a parent particle decaying into two Z bosons. For a spin-1 parent the theorem predicts that (1) there are only two possible couplings and (2) the normalized differential cross section depends on kinematics only through a phase shift in the azimuthal angle between the two decay planes of the Z boson. When the parent is a Z' the two possible couplings are anomaly induced and CP violating, respectively. At the CERN Large Hadron Collider their effects could be disentangled when both Z bosons decay leptonically.     

Search for charged Higgs bosons at LEP in general two Higgs doublet models

A search for pair-produced charged Higgs bosons was performed in the data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189 GeV to 209 GeV. Five different final states, , , , and were considered, accounting for the major expected decays in type I and type II Two Higgs Doublet Models. No significant excess of data compared to the expected Standard Model processes was observed. The existence of a charged Higgs boson with mass lower than 76.7 GeV/c² (type I) or 74.4 GeV/c² (type II) is excluded at the 95% confidence level, for a wide range of the model parameters. Model independent cross-section limits have also been calculated.Received: 30 September 2003, Revised: 12 February 2004, Published online: 8 April 2004     

Doubly charged Higgs bosons

We explore through two simple models, the first in which scalars are treated as fundamental and the second in which they are composite objects, the possibility that representations containing doubly charged scalars may participate in the spontaneous breakdown of the SU(2) × U(1) symmetry of electroweak interactions. We show that such exotic Higgs bosons may posses unsuppressed coupling to pairs of gauge vector bosons and comment on the observability of these charged Higgs bosons through the Cahn-Dawson mechanism in high-energy hadron colliders.     

Gauge and Higgs bosons

The Review summarizes much of particle physics and cosmology.Using data from previous editions,plus 3,062 new measurements from 721 papers,we list,evaluate,and average measured properties of gauge bosons and the recently discovered Higgs boson,leptons,quarks,mesons,and baryons.We summarize searches for hypothetical particles such as supersymmetric particles,heavy bosons,axions,dark photons,etc.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 Higgs Boson Physics,Supersymmetry,Grand Unified Theories,Neutrino Mixing,Dark Energy,Dark Matter,Cosmology,Particle Detectors,Colliders,Probability and Statistics.Among the 117 reviews are many that are new or heavily revised,including new reviews on Pentaquarks and Inflation.     

Z′ bosons, the NuTeV anomaly, and the Higgs boson mass

Fits to the precision electroweak data that include the NuTeV measurement are considered in family universal, anomaly free U(1) extensions of the Standard Model. In data sets from which the hadronic asymmetries are excluded, some of the Z′ models can double the predicted value of the Higgs boson mass, from ～60 to ～120 GeV, removing the tension with the LEP II lower bound, while also modestly improving the χ ² confidence level. The effect of the Z′ models on both m _H and the χ ² confidence level is increased when the NuTeV measurement is included in the fit. Both the original NuTeV data and a revised estimate by the PDG are considered.     

Higgs bosons at the LHC

The investigation of the dynamics responsible for electroweak symmetry breaking is one of the prime tasks of the experiments at the CERN Large Hadron Collider (LHC). In this article, the potential of the ATLAS and CMS experiments for the discovery of a standard model Higgs boson and for Higgs bosons in the minimal supersymmetric extension is summarized. Emphasis is put on those studies which have been performed recently by the experimental collaborations using a realistic simulation of the detector performance. This includes a discussion of the search for Higgs bosons using the vector boson-fusion mode, a discussion on the measurement of Higgs boson parameters as well as a detailed review of the MSSM sector for different benchmark scenarios.     

Heavy Higgs bosons at LEP

Production of a heavy Weinberg-Salam-type neutral Higgs boson at LEP energies is considered. We conclude that the Higgs is unlikely to be detected at LEP if its mass is greater than 150 GeV.