If the smallness of the mass of the sterile neutrino is to be explained by seesaw mechanism, the off-diagonal entries of its mass matrix has to be protected by some symmetry near the electroweak scale. We study a gauge model based on SU(2)qL × SU(2) l L × U(1) q Y × U(1) l Y un-unified gauge group which breaks to SU(2)L × U(1)Y at the TeV region and this serves our purpose. The diagonal element...

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories, which can be made all-loop finite, both in the dimensionless (gauge and Yukawa couplings) and dimensionful (soft supersymmetry breaking terms) sectors. This remarkable property, based on the reduction of couplings at the quantum level, provides a drastic reduction in the number of free parameters, which in turn lead...

Abstract: We introduce a dual lifting of unified gauge theories, the We introduce a dual lifting of unified gauge theories, the first characterized by the isotopies, which are axiompreserving maps into broader structures with positive-definite generalized units used for the representation of matter under the isotopies of the Poincare’ symmetry, and the second characterized by the isodualities, ...

Quantum cosmology may restrict the class of gauge models which unify electroweak and strong interactions. In particular, if one studies the normalizability criterion for the one-loop wave function of the universe in a de Sitter background one finds that the interaction of inflaton and matter fields, jointly with the request of normalizability at one-loop order, picks out non-supersymmetric vers...

We consider the idea of describing quarks and leptons, and their interactions, in terms of gauged supersymmetric generalized nonlinear sigma models. It is found that the best model is the one based on the Kahler manifold E7/sU(4) X U(1)4, with an atipropriate complex structure. The isotropy representation of the manifold is sufficient for embedding three families of quarks and leptons. We as10 ...

Shortly after the construction of the ten-dimensional heterotic string theories, it was realized that a compactification of these theories on Calabi-Yau manifolds could yield four-dimensional supersymmetric Poincaréinvariant vacua with the massless spectrum consisting of minimal supergravity coupled to a chiral non-abelian gauge theory. This was a remarkable development in theoretical physics, ...