Related papers: Treating Top Differently from Charm and Up
We present an extended 331 model with $T'$ discrete flavor symmetry that simultaneously explains the need to have exactly three generations and provides acceptable quark and lepton masses and mixings. New fermionic states and gauge bosons…
The top quark can be naturally singled out from other fermions in the Standard Model due to its large mass, of the order of the electroweak scale. We follow this reasoning in models of pseudo Nambu Goldstone Boson composite Higgs, which may…
It is shown that an idea proposed in 1996 that relates in a qualitatively correct way the inter-family mass hierarchies of the up quarks, down quarks, charged leptons, and neutrinos, can be combined with a predictive scheme recently…
A unified mass matrix model of quarks and leptons with a seesaw-type form $M_f=m M_F^{-1} m$ is proposed on the basis of a non-standard Higgs scenario. The matrix $m$ is provided by U(3)-family nonet bosons $\phi$, and the matrix $M_F$ is a…
We construct a model of quark-lepton unification at the TeV scale based on an $SU(4)$ gauge symmetry, while still having acceptable neutrino masses and enough suppression in flavor changing neutral currents. An approximate $U(2)$ flavor…
A simple breaking of the subnuclear democracy of the quarks leads to a mixing between the second and the third family, in agrement with observation. Introducing the mixing between the first and the second family, one finds an interesting…
We show that, in frameworks of the economical 3-3-1 model, all fermions get masses. At the tree level, one up-quark and two down-quarks are massless, but the one-loop corrections give all quarks the consistent masses. This conclusion is in…
We propose a supersymmetric extension of the anomaly-free and three families nonuniversal $U(1)$ model, with the inclusion of four Higgs doublets and four Higgs singlets. The quark sector is extended by adding three exotic quark singlets,…
M-theory compactified on a $G_2$ manifold with resolved $E_8$ singularities realizes 4d $\mathcal{N} = 1$ supersymmetric gauge theories coupled to gravity with three families of Standard Model fermions. Beginning with one $E_8$ singularity,…
We assume that all quark and lepton $3 \times 3$ mass matrices which appear in the standard model lagrangian (after spontaneous symmetry breaking) with neutrinos treated as Dirac patricles have the triangular form. Such matrices have not…
S3 models offer a low energy approach to describe the observed pattern of masses and mixing, of both quarks and leptons. In this work, we first revisit an S3 model with only one Higgs electroweak doublet, where the flavour symmetry must be…
The observed replication of fermions in three families is undoubtedly a reflection of a deeper symmetry underlying the standard model. In this paper we investigate one very elementary possibility, that physics above the grand unification…
We consider the maximal U(3) horizontal scheme as a handle on fermion masses and mixings. In particular, we attempt to explain the large top Yukawa coupling and the masses and mixing in the two heaviest generations. A simple model is…
We present the details of a deconstructed model that incorporates both Higgsless and top-color mechanisms. The model alleviates the tension between obtaining the correct top quark mass and keeping Delta rho small that exists in many…
We consider the mass generation for the usual quarks and leptons in some supersymmetric models. The masses of the top, the bottom, the charm, the tau and the muon are given at the tree level. All the other quarks and the electron get their…
In this paper we introduce a simple renormalizable model of an extended color gauge sector in which the third-generation quarks couple differently than the lighter quarks. In addition to a set of heavy color-octet vector bosons (colorons),…
We investigate the implications of a seesaw type mass matrix, i.e., $M_f\simeq m_L M_F^{-1} m_R$, for quarks and leptons $f$ under the assumption that the matrices $m_L$ and $m_R$ are common to all flavors (up-/down- and quark-/lepton-…
We present an $S_3$-invariant extension of the SM which is able to account for the mixing both in the quark and the lepton sector. We focus here on the quark sector and present different realizations of the model, according to how many…
Considering the hierarchical structure of fermionic masses and the fermionic flavor mixing puzzles in the Standard Model, we propose to relate them by the see-saw mechanism, i.e. only the third generation of quarks and charged leptons…
A heavy fourth family is an example of new physics which is well defined and familiar in some respects, but which nevertheless has radical implications. In particular it eliminates a light Higgs description of electroweak symmetry breaking.…