Related papers: The Aligned $SU(5) \times U(1)^2$ Model
We show that maximal atmospheric and large solar neutrino mixing can be implemented in SU(5) gauge theories, by making use of the $U(1)_F$ symmetry associated with a suitably defined family number $F$, together with a $\mathbbm{Z}_2$…
We show how to construct supersymmetric three-generation models with gauge group and matter content of the Standard Model in the framework of non-simply-connected elliptically fibered Calabi-Yau manifolds Z. The elliptic fibration on a…
We present a minimal string-inspired supersymmetric $SU(4) \times SU(2)_L \times SU(2)_R$ model, and provide a detailed analysis of the symmetry breaking potential in this model, based on a generalisation of that recently proposed by Dvali,…
It is shown that embedding a four-dimensional flipped SU(5) model in a five-dimensional SO(10) model, preserves the best features of both flipped SU(5) and SO(10). The missing partner mechanism, which naturally achieves both doublet-triplet…
In the context of the supersymmetric flipped $SU(5)\otimes U(1)$ GUT model, we have studied in detail the neutrino mass spectrum, obtaining an approximate formula for the corresponding effective three-generation mass matrix. It is found…
A natural model of realizing the effective supersymmetry is presented. Two sets of the Standard Model-like gauge group $G_1\times G_2$ are introduced, where $G_i=SU(3)_i\times SU(2)_i\times U(1)_i$, which break diagonally to the Standard…
We systematically construct flipped SU(5) X U(1)_X models without and with bulk vector-like particles from F-theory. To realize the decoupling scenario, we introduce sets of vector-like particles in complete SU(5) X U(1) multiplets at the…
We analyze the Higgs doublet-triplet mass splitting problem in the version of flipped SU(5) derived from string theory. Analyzing non-renormalizable terms up to tenth order in the superpotential, we identify a pattern of field vev's that…
We construct a wide class of non-geometric compactifications of type II superstring theories preserving N=1 space-time supersymmetry in four dimensions, starting from Calabi-Yau compactifications at Gepner points. Particular examples of…
We consider alpha'-corrections to Calabi-Yau compactifications of type II string theory. These were discussed from the string worldsheet approach many years ago in terms of supersymmetric non-linear sigma-models by Nemeschansky and Sen as…
We discuss the possibility of finding scenarios, within type IIB string theory compactified on Calabi-Yau orientifolds with fluxes, for realizing gauge mediated supersymmetry breaking. We find that while in principle such scenarios are not…
We show how identification of absolutely flat directions allows the construction of a new class of compactified string theories with reduced gauge symmetry that may or may not be continuously connected to the original theory. We use this…
We consider the possibility of grand unification of the $\mathrm{ SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model in an SU(6) gauge unification group. Two possibilities arise. Unlike other conventional grand unified theories, in SU(6) one…
We construct a 6D supergravity theory which emerges as intermediate step in the compactification of the heterotic string to the supersymmetric standard model in four dimensions. The theory has N=2 supersymmetry and a gravitational sector…
A scheme of simplified smooth hybrid inflation is realized in the framework of supersymmetric $SU(5)$. The smooth model of hybrid inflation provides a natural solution to the monopole problem that appears in the breaking of $SU(5)$ gauge…
Maximally supersymmetric SO(10) and SU(6) unified theories are constructed on the orbifold T^2/(Z_2 x Z'_2), with one length scale R_5 taken much larger than the other, R_6. The effective theory below 1/R_6 is found to be the highly…
We study the $\mu$ problem and the radiative electroweak symmetry breaking in an extended gauge mediation supersymmetry breaking (GMSB) model, in which the messenger fields are assumed to couple to the different singlet fields due to the…
This paper analyses type II string theories in backgrounds which admit an SU(3) x SU(3) structure. Such backgrounds are designed to linearly realize eight out of the original 32 supercharges and as a consequence the low-energy effective…
The conventional supersymmetric grand unified theories suffer from two serious problems, the large mass splitting between doublet and triplet Higgs multiplets, and the too long lifetime of the proton. A unification model based on a…
We discuss an extended SU(2)XU(1) model which naturally leads to mass scales and mixing angles relevant for understanding both the solar and atmospheric neutrino anomalies in terms of the vacuum oscillations of the three known neutrinos.…