Two-body charmed meson decays D → V P are studied within the framework of the diagrammatic approach. Under flavor SU(3) symmetry, all the flavor amplitude sizes and their associated strong phases are extracted by performing a χ 2 fit. Thanks to the recent measurement of D + s → π + ρ 0 , the magnitudes and the strong phases of the W -annihilation amplitudes A P,V have been extracted for the first time. As a consequence, the branching fractions of all the D → V P decays are predicted, especially those modes that could not be predicted previously due to the unknown A P,V . Our working assumption, the flavor SU (3) symmetry, is tested by comparing our predictions with experiment for the singly and doubly Cabibbo-suppressed decay modes based on the flavor amplitudes extracted from the Cabibbofavored decays using the current data. The predictions for the doubly Cabibbo-suppressed channels are in good agreement with the data, while those for the singly Cabibbo-suppressed decay modes are seen to have flavor SU(3) symmetry breaking effects. We find that the inclusion of SU(3) symmetry breaking in color-allowed and color-suppressed tree amplitudes is needed in general in order to have a better agreement with experiment. Nevertheless, the exact flavor SU(3)-symmetric approach alone is adequate to provide an overall explanation for the current data.
We derive the most general sets of viable mass spectra of the exotic Higgs bosons in the Georgi-Machacek model that are consistent with the theoretical constraints of vacuum stability and perturbative unitarity and the experimental constraints of electroweak precision observables, Zbb coupling and Higgs boson signal strengths. Branching ratios of various cascade decay channels of the doubly-charged Higgs boson in the 5 representation, the singly-charged Higgs boson in 3, and the singlet Higgs boson are further computed. As one of the most promising channels for discovering the model, we study the prospects for detecting the doubly-charged Higgs boson that is produced via the vector boson fusion process and decays into final states containing a pair of same-sign leptons at the 14-TeV LHC and a 100-TeV future pp collider. For this purpose, we evaluate acceptance times efficiency for signals of the doubly-charged Higgs boson with general viable mass spectra and compare it with the standard model background estimates.
Current CERN Large Hadron Collider data on the 126 GeV standard model-like
Higgs boson suggest the possibility of larger Higgs boson couplings with the
weak gauge bosons, $g_{hVV}$, than those in the standard model. We use the
Georgi-Machacek model as an explicit model to realize such a scenario. We find
that the $g_{hVV}$ couplings can be larger than the standard model value by a
factor of about 1.3 maximally in the parameter region consistent with the
current Higgs boson search data and allowed by various other constraints. We
then show how the modified $g_{hVV}$ couplings lead to enhancements in various
weak boson scattering processes. This can be clearly observed as excesses in
the transverse mass distributions at around 126 GeV and also the mass of heavy
Higgs bosons.Comment: 18 pages, 14 figure
We calculate 1-loop radiative corrections to the hZZ and hW W couplings in models with nextto-simplest Higgs sectors satisfying the electroweak ρ parameter equal to 1 at tree level: the Higgs singlet model, the two-Higgs doublet models, and the Georgi-Machacek model. Under theoretical and current experimental constraints, the three models have different correlations between the deviations in the hZZ and hW W couplings from the standard model predictions. In particular, we find for each model predictions with no overlap with the other two models.
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