Related papers: Higgs Triplets, Decoupling, and Precision Measurem…
We examine the Higgs mass parameters and electroweak symmetry breaking in supersymmetric orbifold field theories in which the 4-dimensional Higgs fields originate from higher-dimensional gauge supermultiplets. It is noted that such…
Extending the Standard Model by adding a scalar field transforming as a septet under $SU(2)_L$ preserves the $\rho$ parameter at tree level and can satisfy experimental constraints on the electroweak parameters $S$ and $T$. This work…
We demonstrate that Standard Model vacuum stability exhibits extreme sensitivity to the Higgs quartic coupling: a mere 3\% enhancement represents the critical threshold separating metastability from absolute stability with UV Landau poles.…
New physics could manifest itself in the form of electroweak multiplets that interact at tree level with the Higgs boson but do not mix with Standard Model fields or acquire expectation values. In this paper, we study the potential…
In extended Higgs models, a discrete symmetry is needed in the quark sector to avoid tree-level flavor-changing neutral currents. However, this is not necessary the case in the lepton sector. We consider a model in which one Higgs couples…
The measured properties of the recently discovered Higgs boson are in good agreement with predictions from the Standard Model. However, small deviations in the Higgs couplings may manifest themselves once the currently large uncertainties…
The coupling of a composite Higgs to the standard model fields can deviate substantially from the standard model values. In this case perturbative unitarity might break down before the scale of compositeness is reached, which would suggest…
We study the dynamics of electroweak symmetry-breaking in an extension of the Standard Model where the Higgs sector is augmented by the addition of a real (Y = 0) isospin triplet. We show that this scenario exhibits a novel, two-step…
Many models of Beyond the Standard Model physics involve heavy colored fermions. We study models where the new fermions have vector interactions and examine the connection between electroweak precision measurements and Higgs production. In…
We study the phenomenology of the Standard Model (SM) Higgs sector extended by two singlet scalars. The model predicts two CP-even scalars $h_{1,2}$ which are a mixture of doublet and singlet components as well as a pure singlet scalar…
Imposing the theoretical constraints from vacuum stability, unitarity and perturbativity as well as the experimental constraints from the electroweak precision data, flavor observables and the non-observation of additional Higgs at…
In this thesis, we investigate the implications of the LHC Higgs data on different BSM scenarios. Since the data seem to agree with the SM expectations, any nonstandard couplings will be strongly constrained. First we investigate, in a…
Extensions of the Standard Model often come with additional, possibly electroweakly charged Higgs states, the prototypal example being the Two-Higgs-Doublet Model. While collider phenomenology does not exclude the possibility for some of…
The extension of the Higgs sector with an additional complex triplet field is often considered for generating the neutrino mass by the Type-II seesaw mechanism. Such an extension generally predicts $\rho\neq1$, where $\rho$ is the…
The triviality of the scalar sector of the standard one-doublet Higgs model implies that this model is only an effective low-energy theory valid below some cut-off scale Lambda. For a heavy higgs this scale must be relatively low (10 TeV or…
We consider modifications of the Higgs potential due to new physics at high energy scales. These upset delicate cancellations predicted by the Standard Model for processes involving Higgs bosons and longitudinal gauge bosons, and lead to a…
It is shown that, nonminimal coupling between the Standard Model (SM) Higgs field and spacetime curvature, present already at the renormalizable level, can be fine-tuned to stabilize the electroweak scale against power-law ultraviolet…
Contrary to common belief, the requirement that supersymmetry exists and that there are two Higgs doublets and no singlet at the electroweak energy scale does not necessarily result in the minimal supersymmetric standard model (MSSM). An…
We calculate 1-loop radiative corrections to the $hZZ$ and $hWW$ couplings in models with next--to--simplest Higgs sectors satisfying the electroweak $\rho$ parameter equal to 1 at tree level: the Higgs singlet model, the two-Higgs doublet…
A primary goal of present and future colliders is measuring the Higgs couplings to Standard Model (SM) particles. Any observed deviation from the SM predictions for these couplings is a sign of new physics whose energy scale can be bounded…