Related papers: A vector-like heavy quark in the Littlest Higgs mo…
The rare flavour changing top quark decay $t\to cZ$ is a clear sign of new physics and experimentally very interesting due to the huge number of top quarks produced at the LHC. However, there are few (viable) models which can generate a…
The phenomenology of a charged Higgs present in a model with two Higgs SU(2) doublets and a $Z_3$ flavor symmetry is analyzed. It is shown that it is possible to generate an enhancement of its flavor changing coupling to c and b quarks and…
Hints of lepton flavor violation have been observed by LHCb in the rate of the decay $B\to K\mu^+\mu^-$ relative to that of $B\to K e^+e^-$. This can be explained by new scalars and fermions which couple to standard model particles and…
We {works done in collaboration with C.S.Kim, Yonsei Univ., Seoul, Korea} present some properties of the SM with two Higgs doublets. Unlike the minimal SM, the Yukawa couplings (in the usual ``type II'' model) converge with the increasing…
The Standard Model has some intrinsic beauty in the sector of fermions and gauge bosons. Its scalar sector, though minimal, is however haunted by the hierarchy problem. The fermionic spectrum also have two major problems, the flavor problem…
The LHC is a top quark factory and provides a unique opportunity to look for flavour changing neutral current or charged-lepton flavour violating interactions of the top quark. These processes are highly suppressed in the Standard Model and…
In the Minimal Supersymmetric Standard Model squark mixing can significantly change the pattern of charged-Higgs production. We find that non-minimal flavor structures can have a sizeable impact on the charged-Higgs production cross…
New light singlet scalars with flavor-specific couplings represent a phenomenologically distinctive and flavor-safe alternative to the well-studied possibility of Higgs-portal scalars. However, in contrast to the Higgs portal,…
We study the flavor physics in two extensions of the quark sector of the Standard Model (SM): a four generation model and a model with a single vector--like down--type quark (VDQ). In our analysis we take into account the experimental…
We present a $D_4$ flavored extension of the SM which provides an intuitive reasoning for the masses and mixing patterns in the quark sector. In our model, the Cabibbo mixing angle stems purely from the scalar sector dynamics. In fact, the…
We propose a model of generations that has exactly three generations. This model has several attractive features: There is a simple mechanism to produce the CKM quark mixings and their neutrino analogs. There are definite predictions for…
Vector-like quarks (VLQs) are predicted in many new physics scenarios beyond the standard model (SM). We consider a search strategy for vector-like bottom quark (VLQ-$B$) at the LHC in a model independent fashion. Our analysis is based on…
The fundamental constraint on two Higgs doublet models comes from the requirement of sufficiently suppressing flavor-changing neutral currents. There are various standard approaches for dealing with this problem, but they all tend to share…
We discuss the possibility that flavor hierarchies arise from the electroweak scale in a two Higgs doublet model, in which the two Higgs doublets jointly act as the flavon. Quark masses and mixing angles are explained by effective Yukawa…
We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas…
We construct a model of an unparticle sector consisting of a supersymmetric SU(N) gauge theory with the number of flavors in the Seiberg conformal window. We couple this sector to the MSSM via heavy messengers. The resulting low energy…
The littlest Higgs model with discrete symmetry named "T-parity"(LHT) is an interesting new physics model which does not suffer strong constraints from electroweak precision data. One of the important features of the LHT model is the…
We present an ultra-violet extension of the "simplest little Higgs" model. The model marries the simplest little Higgs at low energies to two copies of the "littlest Higgs'' at higher energies. The result is a weakly coupled theory below…
We will investigate the scenario in which the Standard Model (SM) Higgs sector and its 2-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the "portal" for the interactions between the Standard Model and a fermionic Dark…
Aspects of the quark mixings and flavor changing interactions are investigated in electroweak models with singlet quarks. The effects on the ordinary quark mixing are determined in terms of the quark masses and the parameters describing the…