No Arabic abstract
We analyze the effects of introducing vector fermions in the Higgs Triplet Model. In this scenario, the model contains, in addition to the Standard Model particle content, one triplet Higgs representation, and a variety of vector-like fermion states, including singlet, doublet, and triplet states. We investigate the electroweak precision variables and impose restrictions on model parameters. We show that, for some representations, introducing vector quarks significantly alters the constraints on the mass of the doubly charged Higgs boson, bringing it in closer agreement with experimental constraints. We also study the effects of introducing the vector-like fermions on neutral Higgs phenomenology, in particular on the loop-dominated decays H -> gamma gamma and H -> Z gamma, and the restrictions they impose on the parameter space.
The inability to predict neutrino masses and the existence of the dark matter are two essential shortcomings of the Standard Model. The Higgs Triplet Model provides an elegant resolution of neutrino masses via the seesaw mechanism. We show here that introducing vectorlike leptons in the model also provides a resolution to the problem of dark matter. We investigate constraints, including the invisible decay width of the Higgs boson and the electroweak precision variables, and impose restrictions on model parameters. We analyze the effect of the relic density constraint on the mass and Yukawa coupling of dark matter. We also calculate the cross sections for indirect and direct dark matter detection and show our model predictions for the neutrino and muon fluxes from the Sun, and the restrictions they impose on the parameter space. With the addition of vectorlike leptons, the model is completely consistent with dark matter constraints, in addition to improving electroweak precision and doubly charged mass restrictions, which are rendered consistent with present experimental data.
We analyze the effects of introducing vector-like leptons in the Higgs Triplet Model providing the lightest vector-like neutrino as a Dark Matter candidate. We explore the effect of the relic density constraint on the mass and Yukawa coupling of dark matter, as well as calculate the cross sections for indirect and direct dark matter detection. We show our model predictions for the neutrino and muon fluxes from the Sun, and the restrictions they impose on the parameter space. We show that this model, with a restricted parameter space, is completely consistent with dark matter constraints, and indicate the resulting mass region for the dark matter.
We explain the $e^+ e^-$ excess observed by the DAMPE Collaboration using a dark matter model based upon the Higgs triplet model and an additional hidden $SU(2)_X$ gauge symmetry. Two of the $SU(2)_X$ gauge bosons are stable due to a residual discrete symmetry and serve as the dark matter candidate. We search the parameter space for regions that can explain the observed relic abundance, and compute the flux of $e^+ e^-$ coming from a nearby dark matter subhalo. With the inclusion of background cosmic rays, we show that the model can render a good fit to the entire energy spectrum covering the AMS-02, Fermi-LAT and DAMPE data.
We investigate the effect of introducing a sequential generation of chiral fermions in the Higgs Triplet Model with nontrivial mixing between the doublet and triplet Higgs. We use the available LHC data for Higgs boson production and decay rates, the constraints on the fourth generation masses, and impose electroweak precision constraints from the S, T and U parameters. Our analysis shows that an SM-like Higgs boson state at ~125 GeV can be accommodated in the Higgs Triplet Model with four generations, and thus, that four generations survive collider and electroweak precision constraints in models beyond SM.
We perform an exclusive study on the Feebly Interacting Massive Particle (FIMP) dark matter candidate in an extended hyperchargeless ($Y=0$) Higgs triplet model. The additional $Z_2$ odd neutral fermion singlet plays the role of dark matter with support from two other vector-like fermion doublets. The mixing between the neutral component of a doublet and singlet fermions controls the current relic density through the Freeze-in mechanism, whereas the additional doublet fermion helps to get the neutrino mass and mixing angles. We obtain a broad region of the parameter spaces satisfying the current relic density and neutrino mass and mixing angles.