Related papers: Universal Doublet-Singlet Higgs Couplings and phen…
The present upper bound on $\kappa_e$, the ratio between the electron Yukawa coupling and its Standard Model value, is of ${\cal O}(600)$. We ask what would be the implications in case that $\kappa_e$ is close to this upper bound. The…
In the next-to minimal supersymmetric standard model (NMSSM) one additional singlet-like Higgs boson with small couplings to standard model (SM) particles is introduced. Although the mass can be well below the discovered 125 GeV Higgs boson…
We discuss constrained and semi--constrained versions of the next--to--minimal supersymmetric extension of the Standard Model (NMSSM) in which a singlet Higgs superfield is added to the two doublet superfields that are present in the…
In the alignment limit of a multi-doublet Higgs sector, one of the Higgs mass eigenstates aligns in field space with the direction of the scalar field vacuum expectation values, and its couplings approach those of the Standard Model (SM)…
Both the ATLAS and CMS experiments at the LHC have reported the observation of the particle of mass around 125GeV which is consistent to the Standard Model (SM) Higgs boson, but with an excess of events beyond the SM expectation in the…
The Standard Model of electroweak interactions has one scalar doublet. The minimal extension of this sector is effected by adding a neutral, singlet scalar field. Depending on whether the singlet field has a non-zero vacuum expectation…
We give a brief review of beyond-the-Standard Model (BSM) extensions of the Standard Model (SM) Higgs sector. Going from very simple to more complicated models, our survey includes models with additional scalar singlet fields, the Two Higgs…
We investigate the implications of a minimal $SU(2)$ gauge symmetry extension of the standard model at the LHC. To achieve the spontaneous symmetry breaking, a heavy Higgs doublet of the $SU(2)$ is introduced. To obtain an anomaly free…
We discuss the phenomenology of several Beyond the Standard Model (SM) extensions that include extended Higgs sectors. The models discussed are: the SM extended by a complex singlet field (CxSM), the 2-Higgs-Doublet Model with a…
We assume that the 125 GeV Higgs discovered at the LHC is the heavy CP-even Higgs of the two-Higgs-doublet models, and examine the parameter space in the Type-I, Type-II, Lepton-specific and Flipped models allowed by the latest Higgs signal…
Higgs couplings can be affected by physics beyond the Standard Model. We study modifications through interactions with a hidden sector and in specific composite Higgs models accessible at the LHC. Both scenarios give rise to congruent…
Some new physics beyond the Standard Model of particle physics, like Supersymmetry, Extra-dimensions etc., and their effect on the nature of different standard model phenomena are explored in this thesis. We discuss the power law scaling of…
We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state ($H$) appears in addition to the Higgs…
Results from the global Standard Model fit to electroweak precision data, including newest Tevatron measurements, are reviewed and discussed. The complete fit using also the constraints from the direct Higgs boson searches yields an upper…
We obtain the mass spectrum and the Higgs self-coupling of the two Higgs doublet model (THDM) in an alternative unification scenario where the parameters of the Higgs potential $\lambda_i$ ($i=1,2,3,4,5$) are determined by imposing their…
Run I of the LHC has not revealed any sign of new physics beyond the Standard Model (BSM). However, the discovery of an SM-like Higgs boson with mass around 125 GeV opens up new possibilities for probing various BSM scenarios with enlarged…
In view of the absence of any direct sign of New Physics (NP) at the LHC, the precise investigation of the Higgs properties becomes more and more important in our quest for physics beyond the Standard Model (SM). Coupling measurements play…
After the discovery of a Higgs boson at the LHC, the next important step is to measure its couplings to fermions and bosons to unravel its true nature. In order to ultimately test the shape of the scalar potential that triggers the…
We present the current status of the Two-Higgs-Doublet model of type II. Taking into account all available relevant information, we exclude at $95$% CL sizeable deviations of the so-called alignment limit, in which all couplings of the…
In general, there can be mass differences among scalar bosons of the Higgs triplet field with the hypercharge of Y=1. In the Higgs triplet model, when the vacuum expectation value $v_\Delta$ of the triplet field is much smaller than that…