710 research outputs found
Hidden top quark decays to charged Higgs scalars at the Tevatron
Charged Higgs scalars light enough to contribute to top quark decays are
possible in various non--minimal Higgs models. We show that such a decay would
be consistent with the current Tevatron data, and will remain hidden until a
larger luminosity can be achieved.Comment: 17 pages, latex, 6 figure
Fermiophobic Higgs bosons at LEP
This work describes the results of the searches for a Higgs boson decaying
into gauge bosons carried out by the four LEP collaborations: ALEPH, DELPHI, L3
and OPAL. A lower bound of 109.7 GeV is set at 95% confidence level on the mass
of a fermiophobic Higgs boson decaying into photons. This mass limit can be
extended by considering the Higgs decay mode into weak bosons. Such a
combination has been done by the L3 collaboration which extended the
fermiophobic mass by 5 GeV.Comment: Talk presented at the ICHEP02 conference, Amsterdam, July 2002, 3
pages, 4 figure
Radiative corrections to the decay
Full one-loop electroweak corrections to the on-shell decay
are computed in the framework of models with two Higgs doublets (THDM). Such a
decay may be dominant for over a wide range of parameter space
relevant at present and future colliders. We show that the corrections may
approach 40% and in particular are sensitive to , which parametrizes
the discrete symmetry breaking term. We suggest that a measurement of the
branching ratio of may offer a possibility of measuring the
magnitude of .Comment: 27 pages, LaTex, 6 figures, one figure added, appendix shortened. To
be published in Eur. Phys. Jour.
Constraint on the branching ratio of B_c \to tau nu from LEP1 and consequences for R(D(*)) anomaly
Recently there has been interest in the correlation between R(D*) and the
branching ratio (BR) of in models with a charged scalar
H^\pm. Any enhancement of R(D*) by alone (in order to agree with
current data) also enhances ), for which there has been no
direct search at hadron colliders. We show that LEP data taken at the Z peak
requires BR() < 10%, and this constraint is significantly
stronger than the recent constraint BR() < 30% from
considering the lifetime of B_c. In order to respect this new constraint, any
explanation of the R(D) and R(D*) anomaly in terms of alone would
require the future measurements of R(D*) to be even closer to the Standard
Model prediction. A stronger limit on BR() (or its first
measurement) would be obtained if the L3 collaboration used all its data taken
at the Z peak.Comment: 14 pages, 4 figures, a reference and two sentences adde
Level discrimination of speech sounds by hearing-impaired individuals with and without hearing amplification
Objectives: The current study was designed to see how hearing-impaired individuals judge level differences between speech sounds with and without hearing amplification. It was hypothesized that hearing aid compression should adversely affect the user's ability to judge level differences.
Design: Thirty-eight hearing-impaired participants performed an adaptive tracking procedure to determine their level-discrimination thresholds for different word and sentence tokens, as well as speech-spectrum noise, with and without their hearing aids. Eight normal-hearing participants performed the same task for comparison.
Results: Level discrimination for different word and sentence tokens was more difficult than the discrimination of stationary noises. Word level discrimination was significantly more difficult than sentence level discrimination. There were no significant differences, however, between mean performance with and without hearing aids and no correlations between performance and various hearing aid measurements.
Conclusions: There is a clear difficulty in judging the level differences between words or sentences relative to differences between broadband noises, but this difficulty was found for both hearing-impaired and normal-hearing individuals and had no relation to hearing aid compression measures. The lack of a clear adverse effect of hearing aid compression on level discrimination is suggested to be due to the low effective compression ratios of currently fit hearing aids
Estimates of the number of adults in England, Wales, and Scotland with a hearing loss
No abstract available
Dependence of the leptonic decays of H^- on the neutrino mixing angles theta_{13} and theta_{23} in models with neutrinophilic charged scalars
In the Higgs Triplet Model and the neutrinophilic Two-Higgs-Doublet Model the
observed neutrinos obtain mass from a vacuum expectation value which is much
smaller than the vacuum expectation value of the Higgs boson in the Standard
Model. Both models contain a singly charged Higgs boson (H^-) whose Yukawa
coupling is directly related to the neutrino mass (i.e. a "neutrinophilic
charged Higgs"). The partial decay widths of H^- into a charged lepton and a
neutrino (H^- to l^- nu) depend identically on the neutrino masses and mixings
in the two models. We quantify the impact of the recent measurement of
sin^2(2theta_{13}), which plays a crucial role in determining the magnitude of
the branching ratio of H^- to e^- nu for the case of a normal neutrino mass
ordering if the lightest neutrino mass m_0 < 10^{-3} eV. We also discuss the
sizeable dependence of H^- to mu^- nu and H^- to tau^- nu on sin^2(theta_{23}),
which would enable information to be obtained on sin^2(theta_{23}) and the sign
of \Delta m^2_{31} if these decays are measured. Such information would help
neutrino oscillation experiments to determine the CP-violating phase \delta.Comment: 17 pages, 6 figure
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