Related papers: Constraints on coloured scalars from global fits
The supersymmetric contributions to the Flavor Changing Neutral Current processes may be suppressed by decoupling the scalars of the first and second generations. It is known, however, that the heavy scalars drive the stop mass squareds…
Confining hidden sectors at the GeV scale are well motivated by asymmetric dark matter and naturalness considerations and can also give interesting collider signatures. Here we study such sectors connected to the Standard Model by a TeV…
In this dissertation, the Minimal Supersymmetric Standard Model (MSSM) is studied as a low-energy theory stemming from the $SU(5)$ Grand Unified Theory (GUT). We investigate the possibility of satisfying the minimal $SU(5)$ boundary…
In the two Higgs doublet model, perturbativity breaks down below the Planck scale: For top mass values 170-180 GeV, the Yukawa coupling reaches the pole below 1000 TeV, if the ratio of vev's v_u/v_d is below 1. We discuss top condensate…
The LHC is now studying in detail the couplings of the Higgs boson in order to determine if there is new physics. Many recent studies have examined the available fits to Higgs couplings from the perspective of constraining two Higgs doublet…
We consider supersymmetric grand unified theories with soft supersymmetry-breaking scalar masses $m_0$ specified above the GUT scale (super-GUTs) and patterns of Yukawa couplings motivated by upper limits on flavour-changing interactions…
We reconsider the flavor problem in the models with two Higgs doublets. By studying two generation toy models, we look for flavor basis independent constraints on Yukawa couplings that will give us the mass hierarchy while keeping all…
In multi-Higgs-doublet models the alignment in flavour space of the relevant Yukawa matrices guarantees the absence of tree-level flavour-changing couplings of the neutral scalar fields. We analyze the consequences of this condition within…
We analyse the strength of CP violation in an extension of the standard model with an extra $Q=-1/3$ vector-like singlet quark, in the framework of the hypothesis of universality of strength of Yukawa couplings connecting standard quarks.…
We make a comprehensive analysis of an extended supersymmetric model(ESSM) obtained by adding a pair of vector-like families to the minimal supersymmetric standard model and having specific forms of 5 x 5 fermion mass matrices. The singlet…
We study the phenomenology of exotic color-triplet scalar particles $X$ with charge $|Q|=2/3, 4/3,5/3,7/3,8/3$ and $10/3$. If $X$ is a non-singlet of $SU(2)_W$ representation, mass splitting within the multiplet allows for cascade decays of…
Color scalars are salient features of non-minimal SU(5) model, where Higgs sector is extended by 45-dimensional multiplet. We show that gauge coupling unification can be realized in this model with TeV octet scalar and intermediate (~10^6…
We investigate the standard model (SM) with the extension of a charged scalar having fractional electromagnetic charge of $-1/3$ unit and with lepton and baryon number violating couplings at tree level. Without directly taking part in the…
The smallness of fermion masses and mixing angles has recently been been attributed to approximate global $U(1)$ symmetries, one for each fermion type. The parameters associated with these symmetry breakings are estimated here directly from…
Higgs couplings to charged leptons form an important measurement to understand not only the Standard Model (SM), but also physics Beyond Standard Models (BSM). In this work, we update the bounds on the Flavor-Violating (FV) Higgs couplings…
With the hypothesis of minimal flavor violation, we find that there exists a power-aligned relation between the Yukawa couplings of the two scalar doublets in the two-Higgs-doublet model with Hermitian Yukawa matrices. Within such a…
The scale of neutrino masses and the Planck scale are separated by more than twenty-seven order of magnitudes. However, they can be linked by imposing the stability of the electroweak (EW) vacuum. The crucial ingredient is provided by the…
Measurements of Higgs boson Yukawa couplings to Standard Model (SM) fermions constrain radiative mass models for those species. Such models, motivated by the observed fermion mass hierarchy, act as foils for the SM tree-level mechanism: we…
We consider two Higgs doublet models with a softly broken U(1) symmetry, for various limiting values of the scalar mixing angles $\alpha$ and $\beta$. These correspond to the Standard Model Higgs particle being the lighter CP-even scalar…
The two-Higgs doublet model (2HDM) provides an excellent benchmark to study physics beyond the Standard Model (SM). In this work we discuss how the behaviour of the model at high energy scales causes it to have a scalar with properties very…