Related papers: New Vector-Like Fermions and Flavor Physics
We propose a bottom-up approach that a structure of a high-energy physics is explored by accumulating existence proofs and/or no-go theorems in the standard model or its extension. As an illustration, we study fermion mass hierarchies based…
We perform an extensive study of flavor observables in a 2HDM with generic Yukawa structure (the decoupling limit of the MSSM). We examine the effects in flavor physics and constrain the model both from tree-level processes and…
We extend the Zee model by introducing a vector-like lepton doublet and a flavor dependent global $U(1)$ symmetry. Flavor changing neutral currents in the quark sector can be naturally forbidden at tree level due to the $U(1)$ symmetry,…
The flavor structure of quarks and leptons is not yet fully understood, but it hints a more fundamental theory of non-universal generations. We therefore propose a simple extension of the Standard Model by flipping (i.e., enlarging) the…
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…
We propose a tri-hypercharge (TH) embedding of the Standard Model (SM) in which a separate gauged weak hypercharge is associated with each fermion family. In this way, every quark and lepton multiplet carries unique gauge quantum numbers…
We present an SU(12) unification model with three light chiral families, avoiding any external flavor symmetries. The hierarchy of quark and lepton masses and mixings is explained by higher dimensional Yukawa interactions involving Higgs…
We have witnessed some flavor anomalies appeared in the past years, and explanations based on extended gauge sectors are among the most popular solutions. These beyond the Standard Model (SM) theories often assume flavor changing…
We present a model where all fermions are contained in a single irreducible representation of an SU(19) gauge symmetry group. If there is only one scalar field, Yukawa interactions are controlled by a single number rather than by one or…
We reconsider models of fermion masses and mixings based on a gauge anomalous horizontal U(1) symmetry. In the simplest model with a single flavon field and horizontal charges of the same sign for all Standard Model fields, only very few…
Motivated by flavor non-universality and anomalies in semi-leptonic B-meson decays, we present a general and systematic discussion about how to construct anomaly-free $U(1)'$ gauge theories based on an extended standard model with only…
Numerical correlations between fermion masses and mixings could indicate the presence of a flavor symmetry at high energies. In general, the search for these correlations using low-energy data requires an estimate of leading-log radiative…
In orbifold models, gauge, Higgs and the matter fields can be unified in one multiplet from the compactification of higher dimensional supersymmetric gauge theory. We study how three families of chiral fermions can be unified in the gauge…
In the simplest examples of models with a discrete quark-lepton symmetry, an electroweak symmetry breaking sector with more than one Higgs doublet is necessary to obtain the correct mass relations between quarks and leptons. A two Higgs…
We study a minimal extension to the Standard Model with an additional real scalar triplet, $\Sigma$, and a single vector-like quark, $T$. This class of models appear naturally in extensions of the Littlest Higgs model that incorporate dark…
We consider the U(1)$_X$ model, which can induce the flavor violating couplings through vectorlike fermions and address the observed rare $B$-meson decay anomalies. To be consistent with all the other observations, both the associated gauge…
We investigate asymptotically safe extensions of the Standard Model with new matter fields arising in the TeV energy range. The new sector contains singlet scalars and vector-like fermions in representations which permit Yukawa interactions…
We have considered a general 5D warped model with SM fields propagating in the bulk and computed explicit expressions for oblique and non-oblique electroweak observables as well as for flavor and CP violating effective four-fermion…
We explore the possibility that the semi-leptonic $B$ decay ratios $R_{K^{(*)}}$ which violate $\mu - e$ universality are related to the origin of the fermion Yukawa couplings in the Standard Model. Some time ago, a vector-like fourth…
Beyond Standard Model physics frequently connects flavor symmetry with a discrete group. If the discrete symmetry arises spontaneously from a gauge theory, one can maintain compatibility with quantum gravity and avoid anomalies. We provide…