Related papers: Constraints on Heavy Neutral Leptons interacting w…
We study a two-Higgs doublet model extended with an additional singlet scalar (2HDM+S), and provide a brief introduction to the model and its parameters. Constraints are applied to the parameter space of this model in order to accommodate a…
The naturalness of a Higgs boson with a mass near 125 GeV is explored in a variety of weak-scale supersymmetric models. A Higgs mass of this size strongly points towards a non-minimal implementation of supersymmetry. The Minimal…
In the framework of strongly interacting dynamics for electroweak symmetry breaking, heavy composite particles may arise and cause observable effects, as they should couple strongly to the resulting Higgs boson and affect the signals that…
A simple model to accomodate light sterile neutrinos naturally with large mixing with the usual neutrinos has been proposed. The standard model gauge group is extended to include an $SU(2)_S$ gauge symmetry. Heavy triplet higgs scalars give…
We study a class of nonstandard interactions of the newly discovered 125 GeV Higgs-like resonance that are especially interesting probes of new physics: flavor violating Higgs couplings to leptons and quarks. These interaction can arise in…
We study a simplified model of two colourless heavy vector resonances in the singlet representation of $SU(2)_{L}$, with zero and unit hypercharge. We discuss mixing with the Standard Model gauge bosons due to electroweak symmetry breaking,…
If the standard model Higgs boson were much heavier, it would appear as a broad resonance since its decay into a pair of longitudinally polarized gauge bosons is highly enhanced. We study whether the same enhancement happens at loop level…
The neutrinophilic two-Higgs-doublet model ($\nu$2HDM) provides a natural way to generate tiny neutrino mass from interactions with the new doublet scalar $\Phi_\nu$ ($H^\pm,~H,~A$) and singlet neutrinos $N_R$ of TeV scale. In this paper,…
We construct simple renormalizable extensions of the standard model where the leading baryon number violating processes have $\Delta B = \pm \Delta L = -2$. These models contain additional scalars. The simplest models contain a color…
The influence of massless scalar singlets on Higgs signals is discussed. It is shown, that in the case of strong interactions between the Higgs boson and the singlet fields, signals could be suppressed in such a way, that detection of the…
To investigate the possible effects of a light hidden sector on Higgs boson detection, we discuss a model of scalar singlets coupled to the Standard Model. The model effectively makes the Higgs width a free parameter due to additional…
The existence of non-zero neutrino masses points to the likely existence of multiple SM neutral fermions. When such states are heavy enough that they cannot be produced in oscillations, they are referred to as Heavy Neutral Leptons (HNLs).…
We discuss same-sign dilepton resonances in the simplified model approach. The relevant $SU(3}_Q^J$ quantum numbers are $1_2^{0,1,2}$. For simplicity, we only consider a spin 0 scalar, which is typically referred to as a doubly charged…
The discovery of non-zero neutrino masses points to the likely existence of multiple SM neutral fermions. When such states are heavy enough that they cannot be produced in oscillations, they are referred to as Heavy Neutral Leptons (HNLs).…
Motivated by the new observed scalar boson of 126 GeV at ATLAS and CMS, various phenomena in two-Higgs-doublet model (THDM) are investigated broadly in the literature. For considering the model that possesses a solution to the massive…
In a number of Higgs-portal models, an $SU(2)$ isospin-singlet scalar boson generically appears at the electroweak scale and can mix with the Standard Model (SM) Higgs boson with a mixing angle $\alpha$. This singlet scalar boson can have…
A search for a new heavy scalar particle $X$ decaying into a Standard Model (SM) Higgs boson and a new singlet scalar particle $S$ is presented. The search uses a proton-proton ($pp$) collision data sample with an integrated luminosity of…
We explore scalar dark matter that is part of a lepton flavor triplet satisfying symmetry requirements under the hypothesis of minimal flavor violation. Beyond the standard model, the theory contains in addition three right-handed neutrinos…
Heavy Neutral Leptons (HNLs) are hypothetical particles predicted by many extensions of the Standard Model. These particles can, among other things, explain the origin of neutrino masses, generate the observed matter-antimatter asymmetry in…
In the simplest little Higgs model the new flavor-changing interactions between heavy neutrinos and the Standard Model leptons can generate contributions to some lepton flavor violating decays of $Z$-boson at one-loop level, such as $Z \to…