Related papers: Fundamental Composite 2HDM: SU(N) with 4 flavours
The Dark 2HDM (called also the Inert Doublet Model) is the version of the Two-Higgs-Doublet Model with an exact $Z_2$ symmetry. It contains the SM-like Higgs boson $h$ and dark scalars $H$,$H^+,H^-$,$A$. Only dark scalars have odd $Z_2$…
Properties of the Z_2-symmetric Two Higgs Doublet Models (2HDM) are discussed and confronted with new LHC data for a 125 GeV Higgs particle. The particle discovered at LHC in 2012 has properties expected for it in the Standard Model (SM),…
We study the textures of SM fermion mass matrices and their mixings in a supersymmetric adjoint SU(5) Grand Unified Theory with modular $S_4$ being the horizontal symmetry. The Yukawa entries of both quarks and leptons are expressed by…
We present a supersymmetric extension of the Standard Model in which only one electroweak doublet acquires a vacuum expectation value and gives mass to Standard Model fermions. As well as the novel accommodation of a Standard Model Higgs…
We perform a detailed study of a specific Two Higgs Doublet Model (2HDM) with a U(1) gauge symmetry, instead of a typical Z2 discrete symmetry, containing a very light gauge boson Z' (GeV scale or below). The Standard Model (SM) fermions do…
In the type-II seesaw mechanism, the neutrino mass generation could be tested experimentally if the Higgs triplet is at the TeV scale and has a small cubic coupling to the standard model Higgs doublet. We show such small triplet-doublet…
The SU(4) gauge theory with two flavors of Dirac fermions in the sextet representation shares features of a candidate for a composite Higgs model. The analogue of the Higgs multiplet of the Standard Model lives in the Goldstone manifold…
We extend the $SU(3)_c \times SU(2)_L \times U(1)_Y$ standard model by a $U(1)_{Y'}$ gauge symmetry. Three right-handed neutrinos are introduced to cancel the gauge anomaly. One Higgs singlet is responsible for spontaneously breaking the…
We describe our recent lattice study of SU(4) gauge theory with fermions in the fundamental and sextet representations. In this theory, a new type of baryon consists of quarks in both representations. The spectrum of these "chimera baryons"…
The $SU(3)_c^{}\times SU(2)_L^{} \times U(1)_Y^{}$ standard model is extended by a $U(1)_{B-L}^{}$ gauge symmetry with four right-handed neutrinos. Because of their Yukawa couplings to a Higgs singlet for spontaneously breaking the…
We propose a two Higgs doublet Type III seesaw model with $\mu$-$\tau$ flavor symmetry. We add an additional SU(2) Higgs doublet and three SU(2) fermion triplets in our model. The presence of two Higgs doublets allows for natural…
We consider a conformal complex singlet extension of the Standard Model with a Higgs portal interaction. The global $U(1)$ symmetry of the complex singlet can be either broken or unbroken and we study each scenario. In the unbroken case,…
We use lattice simulations to compute the baryon spectrum of SU(4) lattice gauge theory coupled to dynamical fermions in the fundamental and two-index antisymmetric (sextet) representations simultaneously. This model is closely related to a…
We argue that the A_4 symmetry as required by three flavors of fermions may well-embed in the SU(3)_C X SU(3)_L X U(1)_X gauge model. The new neutral fermion singlets as introduced in a canonical seesaw mechanism can be combined with the…
We propose a Three Higgs Doublet Model (3HDM) that goes beyond natural flavor conservation and in which each of the three Higgs doublets couples mainly to a single generation of fermions via non-standard Yukawa structures. A hierarchy in…
We consider the unification of gauge, Higgs as well as the matter fields in a 6D N=2 supersymmetric SU(8) gauge theory. The gauge symmetry SU(8) is broken down to SU(4) x SU(2)_L x SU(2)_R x U(1)^2 in 4D through T^2/Z_6 orbifold…
We discuss a dark family of lepton-like particles with their own "private" gauge bosons under a local SU'(2)xU'(1) symmetry. The product of dark and visible gauge groups SU'(2)xU'(1)xSU_w(2)xU_Y(1) is broken dynamically to the diagonal…
The flavour structure of the general Two Higgs Doublet Model (2HDM) is analysed and a detailed study of the parameter space is presented, showing that flavour mixing in the 2HDM can be parametrized by various unitary matrices which arise…
We analyse the interplay of the constraints imposed on flavour-symmetric Composite Higgs models by Naturalness considerations and the constraints derived from Flavour Physics and Electroweak Precision Tests. Our analysis is based on the…
We propose a fundamental theory whose low-energy effective theory provides a phenomenological description of electroweak baryogenesis, radiative neutrino mass generation, and dark matter. The model is based on SUSY SU(2)_H gauge theory with…