Related papers: Variants of the Standard Model with Electroweak-Si…
Small Dirac masses for neutrinos are natural in models with singlet fermions in large extra dimensions with quantum gravity scale M_{\ast} \sim 1- 100 TeV. We study two modifications of the minimal model in order to obtain the mass scale…
We consider large classes of chiral extensions of the Standard Model, including new quark generations that do not involve additional neutrinos as well as lepton generations without quarks. An analysis of renormalization flows of Yukawa and…
In the chiral $SU(15)$ gauge theory presented here, the quarks and leptons are bound states ("prebaryons") of massless preons. The Standard Model charges of the preons imply 3 generations of quarks and leptons, plus some vectorlike fermions…
The Standard Model of electroweak and strong interactions is reviewed in a pedagogical set of lectures. After an introduction to the quarks, leptons, and gauge bosons, an elementary discussion of gauge theories is given, with application to…
An unorthodox unified theory is developed to describe external and internal attributes and symmetries of fundamental fermions, quarks and leptons. Basic ingredients of the theory are an algebra which consists of all the…
In the context of the gauge coupling unification, we present a comprehensive analysis of the extensions of the Standard Model with vector-like fermions and scalars. We find 145 models that satisfy the unification condition, which are…
For all the success of the Standard Model (SM), it is on the verge of being surpassed. In this regard we argue, by showing a minimal flavor-structured model based on the non-Abelian discrete $SL_2(F_3)$ symmetry, that $U(1)$…
One of the simplest extensions of the Standard Model is the inclusion of an additional scalar multiplet, and we consider scalars in the $SU(2)_L$ singlet, triplet, and quartet representations. We examine models with heavy neutral scalars,…
In this paper we construct non-Abelian gauge theories with fermions and scalars that nevertheless possess asymptotic freedom.The scalars are taken to be in a chiral multiplet transforming as $(2,2)$ under $SU(2)_L\otimes SU(2)_R$ and…
A composite model of the fundamental fermions based on colour preons is discussed. It is found that, if endowed with the pairwise (repulsive/attractive) chromoelectric fields, preons would cohere in a series of structures, resembling by…
We derive the Feynman rules of the standard model in the axial gauge. After this we prove that the fields $\phi_W$ and $\phi_Z$ do not correspond to physical particles. As a consequence, these fields cannot appear as incoming or outgoing…
We propose a minimal extension of the Standard Model by incorporating sterile neutrinos and a QCD axion to account for the mass and mixing hierarchies of quarks and leptons and to solve the strong CP problem, and by introducing $G_{\rm…
We derive an effective dimensionally reduced theory for the Standard Model augmented by a real singlet scalar. We treat the singlet as a superheavy field and integrate it out, leaving an effective theory involving only the Higgs and…
We study the scattering of fermions off 't Hooft lines in the Standard Model. A long-standing paradox suggests that the outgoing fermions necessarily carry fractional quantum numbers. In a previous paper, we resolved this paradox in the…
We propose a supersymmetric technicolor model in which the electroweak symmetry breaking is communicated to the quarks and leptons by technicolored $SU(2)_W$-singlet scalars. When the technifermions condense, the quarks and leptons of the…
The neutron electric dipole moment is investigated in a supersymmetric electroweak model admitting $ {\rm SU(2)}_W $ singlet and $ Q = -1/3 $, say $ D $-type, quarks. Significant $ CP $ violating phases appear in the coupling between the…
The model of radiative neutrino mass with dark matter proposed by one of us is extended to include a real singlet scalar field. There are then two important new consequences. One is the realistic possibility of having the lightest neutral…
The standard model for electroweak interactions uses the concepts of weak hypercharge and local gauge invariance of the Lagrangian density under the gauge group SU(2) x U(1). Taylor has remarked that U(1), being a multiply-connected group,…
We construct extensions of the Standard Model in which the gauge symmetries and supersymmetry prevent the dangerously large effects that may potentially be induced in a supersymmetric standard model by Planck scale physics. These include…
I briefly describe the recent construction of the first specific string D-brane models yielding just the SM massless fermion spectrum. One of the most remarkable facts predicted by these constructions is that the global symmetries of the SM…