相关论文: Supersymmetric SU(5) GUT with Stabilized Moduli

We systematically analyse globally consistent SU(5) GUT models on intersecting D7-branes in genuine Calabi-Yau orientifolds with O3- and O7-planes. Beyond the well-known tadpole and K-theory cancellation conditions there exist a number of…

String compactifications with D-branes may exhibit regular magnetic monopole solutions, whose presence does not rely on broken non-abelian gauge symmetry. These stringy monopoles exist on interesting metastable brane configurations, such as…

We study a five dimensional nonsupersymmetric SU(3) gauge theory compactified on $M^4\times S^1/Z_2$. The gauge hierarchy is discussed in the scenario of the gauge-Higgs unification. We present two models in which the large gauge hierarchy…

We study a class of flux compactifications that have all the moduli stabilised, a high (GUT) string scale and a low (TeV) gravitino mass that is generated dynamically. These non-geometric compactifications correspond to type II string…

$\mathcal{G}$-structures, where $\mathcal{G}$ is a Lie group, are a uniform characterisation of many differential geometric structures of interest in supersymmetric compactifications of string theories. Calabi-Yau $n$-folds are instances of…

We construct an N=1 supersymmetric three-family flipped SU(5) model from type IIA orientifolds on $T^6/(\Z_2\times \Z_2)$ with D6-branes intersecting at general angles. The model is constrained by the requirement that Ramond-Ramond tadpoles…

We construct a supersymmetric grand unified model in the framework of a latticized extra dimension. The SU(5) symmetries on the lattice are broken by the vacuum expectation values of the link fields connecting adjacent SU(5) sites, leaving…

We consider four-dimensional supersymmetric compactifications of the E8 x E8 heterotic string on Calabi-Yau manifolds endowed with vector bundles with structure group SU(N) x U(1) and five-branes. After evaluating the Green-Schwarz…

We study a grand unified SU(5)xSU(5)' model supplemented by D2 parity. The D2 greatly reduces the number of parameters and is important for phenomenology. The model, we present, has various novel and interesting properties. Because of the…

The idea of quark-lepton universality at high energies has been introduced as a natural extension to the standard model. This is achieved by endowing leptons with new degrees of freedom -- leptonic colour, an analogue of the familiar quark…

In the context of the standard SUSY GUT scenario, we present a detailed analysis of the softly broken finite supersymmetric grand unified theory. The model, albeit non-minimal, remains very rigid due to the requirement of finiteness. It is…

We point out that type I string theory in the presence of internal magnetic fields provides a concrete realization of split supersymmetry. To lowest order, gauginos are massless while squarks and sleptons are superheavy. We build such…

We present an extensive search for a general class of flipped $SU(5)$ models built within the free fermionic formulation of the heterotic string. We describe a set of algorithms which constitute the basis for a computer program capable of…

Based on the Z_{12-I} orbifold compactification of the heterotic string theory, we construct a flipped-SU(5) model with three families of the standard model matter and ingredients for dynamical supersymmetry breaking. The doublet-triplet…

We construct and discuss a "realistic" example of SUSY SU(5) GUT model, with an additional U(1) flavour symmetry, that is not plagued by the need of large fine tunings, like those associated with doublet-triplet splitting in the minimal…

Scherk-Schwarz compactification in string theory can be defined as orbifolding by an R symmetry, a symmetry that acts differently on bosons and fermions. Such a symmetry can arise in many situations, including toroidal and orbifold…

We study grand unified models in the five-dimensional space-time where the extra dimension is compactified on $S^1/Z_2$. The spontaneous breaking of unified gauge symmetries is achieved via vacuum expectation values of the extra-dimensional…

The semi-simple unification model based on SU(5)_GUT \times U(3)_H gauge group is an interesting extension of the minimal SU(5)_GUT grand unification theory (GUT), since it solves the two serious problems in the standard GUT: the…

The spontaneous breaking of $SO(10)$ via flipped $SU(5)$ to the Standard Model yields a novel scenario in which the superheavy topologically stable GUT monopole carrying a single unit ($2\pi/e$) of Dirac magnetic charge emerges from the…

The Standard Model (SM) is a chiral theory, where right- and left-handed fermion fields transform differently under the gauge group. Extra fermions, if they do exist, need to be heavy otherwise they would have already been observed. With no…