Related papers: Nonstandard Higgs Decays with Visible and Missing …
The crucial search for the Higgs boson at future colliders is capable of discovering the Standard Model Higgs, but is not guaranteed to discover a Higgs that decays nonstandardly. Such new physics is motivated by many aspects; from…
In these lectures we present a brief review of the Higgs boson sector in the ``Standard Model'', and its Minimal Supersymmetric Extension, with particular emphasis on the main mechanisms for Higgs production and decay at LEP2 and LHC, and…
A search for a Higgs boson produced in e^+e^- collisions in association with a Z boson and decaying into invisible particles is performed. Data collected at LEP with the L3 detector at centre-of-mass energies from 189 GeV to 209 GeV are…
This review summarizes the motivations for and phenomenological consequences of nonstandard Higgs boson decays, with emphasis on final states containing a pair of non-Standard-Model particles that subsequently decay to Standard Model…
Results from several recent experiments provide inderect evidences in the favor of existence of a 4th generation neutrino. Such a neutrino of mass about 50 GeV is compatible with current physical and astrophysical constraints and well…
Searches for HZ production with the Higgs boson decaying into an invisible final state were performed using the data collected by the DELPHI experiment at centre-of-mass energies between 188 GeV and 209 GeV. Both hadronic and leptonic final…
Recent LEP searches for Higgs bosons in models other than the Minimal Standard Model and the Minimal Supersymetric Standard Model are reviewed. Limits are presented for Higgs bosons decaying into diphotons or invisible particles, and for…
The Higgs particle can have dominantly invisible decay in a large class of Majoron models as well as some SUSY models. The LEP signal and mass limit for a Higgs particle undergoing invisible decay are explored. They are found to be very…
This paper describes a topological search for an invisibly decaying Higgs boson,H, produced via the Bjorken process (e+e- -> HZ). The analysis is based on data recorded using the OPAL detector at LEP at centre-of-mass energies from 183 to…
Both Atlas and CMS have reported a discovery of a Standard Model-like Higgs boson $H$ of mass around 125 GeV. Consistency with the Standard Model implies the non-observation of non-SM like decay modes of the newly discovered particle.…
Depending on the Higgs-boson and top-quark masses, $M_H$ and $M_t$, the effective potential of the {\bf Standard Model} can develop a non-standard minimum for values of the field much larger than the weak scale. In those cases the standard…
Searches for neutral Higgs bosons are performed with the 237 pb-1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of…
In the year 2000 the four LEP experiments have collected data at energies between 200 and 209 GeV, for approximately 868 pb-1 integrated luminosity. The LEP working group for Higgs boson searches has combined these data with earlier data…
We study the implications of the absence of a direct discovery of a Higgs boson at LEP. First we exhibit 15 physically different ways in which one or more Higgs bosons lighter than the LEP limit could still exist. In the minimal…
In this note, we explore the Tevatron and LHC detection prospects for a nonstandard Higgs whose decays contain both missing and visible energy. In particular, we consider the decay $h \to \chi_2 \chi_1$ where $\chi_1$ is stable and $\chi_2$…
We study the potential of LEP II to unravel the existence of invisibly decaying Higgs bosons, predicted in a wide class of models. We perform a model independent analysis, focusing our attention to the final state topologies exhibiting $b…
A search is conducted for a new beyond-the-Standard-Model boson using events where a Higgs boson with mass 125 GeV decays to four leptons ($\ell =$ $e$ or $\mu$). This decay is presumed to occur via an intermediate state which contains one…
Results are reported from a search for non-standard-model Higgs boson decays to pairs of new light bosons, each of which decays into the oppositely charged dimuon final state. The new bosons may be produced either promptly or via a decay…
A search for a Higgs boson decaying into invisible particles is performed using the data collected at LEP by the L3 experiment at centre-of-mass energies of 183 GeV and 189 GeV. The integrated luminosities are respectively 55.3 pb^-1 and…
We derive model-independent constraints on Higgs mass and couplings from associated signals for higher masses, accessible at LEP2. This work is motivated by the fact that, in many extensions of the standard model, the Higgs boson can have…