Related papers: Unification with and without Supersymmetry: Adjoin…
A complete 5-dimensional SU(5) unified theory is constructed which, on compactification on the orbifold with two different Z_2's (Z_2 and Z_2'), yields the minimal supersymmetric standard model. The orbifold accomplishes SU(5) gauge…
The seesaw mechanism is attractive not only because it "explains'' small neutrino mass, but also because of its packaging with the SUSY-GUT, leptogenesis, Dark Matter, and electroweak symmetry breaking. However, this package has the flavor,…
In the extension of the standard model with one right-handed neutrino and one Higgs triplet, we propose a suppression mechanism, obtaining small masses for the active neutrinos, while mixing angles are predicted with a right-handed neutrino…
The minimal supersymmetric standard model (MSSM) of particle interactions is extended to include three singlet (right-handed) neutrino superfields together with three other singlet superfields. The resulting theory is assumed to be…
We build explicit supersymmetric unification models where grand unified gauge symmetry breaking and supersymmetry (SUSY) breaking are caused by the same sector. Besides, the SM-charged particles are also predicted by the symmetry breaking…
We show that the simplest supersymmetric scenario where a large Higgs mass can be attained at tree-level for any ratio of the Higgs vacuum expectation values corresponds to the case where the neutrino masses are generated through the type…
We study (non-renormalizable) five dimensional supersymmetric field theories. The theories are parametrized by quark masses and a gauge coupling. We derive the metric on the Coulomb branch exactly. We use stringy considerations to learn…
We review in this talk various SUSY SO(10) models. Specifically, we discuss how small neutrino masses are generated in and generic predictions of different SO(10) models. A comparison of the predictions of these models for…
General classes of mechanisms for generating small neutrino masses are surveyed from a top-down (superstring) perspective. In particular, string constructions have motivated various possibilities involving higher-dimensional operators,…
We present a simple observation for neutrino mixings and masses which arises naturally in dimensional deconstruction models. There are two essential ingredients of such models: (i) the presence of a symmetry mediated by the link fields…
I review the unification of gauge couplings of strong, weak and electro-magnetic interactions. I start by recalling the history of the most important prediction of low-energy supersymmetry: the correct value of the weak mixing angle tied to…
After summarizing neutrino oscillation results I discuss high and low-scale seesaw mechanisms, with or without supersymmetry, as well as recent attempts to understand the pattern of neutrino mixing from flavor symmetries. I also mention the…
We account for the solar and atmospheric neutrino problems by introducing maximal mixing between conventional and sterile neutrino partners. We achieve this by invoking a seesaw-like mechanism which not only provides us with maximally mixed…
We perform a systematic analysis of Standard Model extensions with an additional anomaly-free gauge $U(1)$ symmetry, to generate tree-level Dirac neutrino masses. An anomaly-free symmetry demands nontrivial conditions on the charges of the…
The Standard Model of particle physics may seem complicated and arbitrary, but it has hidden patterns that are revealed by the relationship between three "grand unified theories": theories that unify forces and particles by extending the…
These lectures begin with a brief introduction to the minimal supersymmetric standard model (MSSM) and the various mechanisms for hidden sector supersymmetry breaking and go on to provide a pedagogical discussion of the various kinds of…
The radiative seesaw mechanism proposed recently is minimally extended to include supersymmetry in a specific model. Relevant related issues such as leptogenesis and dark matter are discussed.
A fully realistic unified theory is constructed, with SU(5) gauge symmetry and supersymmetry both broken by boundary conditions in a fifth dimension. Despite the local explicit breaking of SU(5) at a boundary of the dimension, the large…
We study phenomenological aspects of supersymmetric SU(5) grand unified theories with non-universal gaugino masses. For large tan beta, we investigate constraints from the requirement of successful electroweak symmetry breaking, the…
We discuss the anomalous U(1) gauge symmetry as a mechanism of generating the grand-unification scale. We conclude that unification to a simple group cannot be realized unless some parameters are ``tuned'', and that models with product…