Related papers: Variations of the Hidden Sector in a Realistic Int…
We construct new supersymmetric SU(5) Grand Unified Models based on Z4 x Z2 orientifolds with intersecting D6-branes. Unlike constructions based on Z2 x Z2 orientifolds, the orbifold images of the three-cycles wrapped by D6-branes…
We study the transition between parallel and intersecting branes on a torus. Spontaneous symmetry breaking of nonabelian gauge symmetry is understood as brane separation, and a more general intermediate deformation is discussed. We argue…
We discuss issues related to orientifolds and the brane realization for gauge theories with orthogonal and symplectic groups. We specifically discuss the case of theories with (hidden) global SO(2n) symmetry, from three to six dimensions.…
In this paper, globally N=1 supersymmetric configurations of intersecting D6-branes on the Z6-orientifold are discussed, involving also fractional branes. It turns out rather miraculously that one is led almost automatically to just ONE…
A supersymmetric Pati-Salam model with wrapping number equal to 5 has been constructed in Type IIA orientifolds on $\mathbf{T}^6/(\mathbb{Z}_2\times \mathbb{Z}_2)$ with intersecting D6-branes recently. In particular, the string-scale gauge…
We consider freely acting orbifold compactifications, which interpolate in two possible decompactification limits between the supersymmetric type II string and the non-supersymmetric type 0 string. In particular we discuss how D-branes are…
The Two Higgs Doublet Model invariant under the gauge group SU(2)xU(1) is known to have six additional global discrete or continuous symmetries of its scalar sector. We have discovered regions of parameter space of the model which are basis…
Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…
In both scotogenic neutrino and flavor dark matter models, the dark sector communicates with the standard model fermions via Yukawa portal couplings. We propose an economic scenario that scotogenic neutrino and flavored mediator share the…
We study the minimal supersymmetric standard model derived from the $Z_8$ orbifold models and its hidden sectors. We use a target-space duality anomaly cancellation so as to investigate hidden sectors consistent with the MSSM unification.…
We construct supersymmetric composite models of quarks and leptons from type IIA T^6/(Z_2 x Z_2) orientifolds with intersecting D6-branes. In case of T^6 = T^2 x T^2 x T^2 with no tilted T^2, a composite model of the supersymmetric SU(5)…
Based on the DBI action for the four coincident non-BPS D9-branes in the type IIA string theory we demonstrate that the gauge symmetry breaking through the tachyon condensation into the generalized monopole of codimension five produces a…
The sequestering of supersymmetry (SUSY) breaking parameters, which is induced by superconformal hidden sector, is one of the solutions for the mu/B_mu problem in gauge-mediated SUSY-breaking scenario. However, it is found that the minimal…
We study the presence of abelian discrete symmetries in globally consistent orientifold compactifications based on rational conformal field theory. We extend previous work [1] by allowing the discrete symmetries to be a linear combination…
Obtaining realistic supersymmetry preserving vacua in the minimal renormalizable supersymmetric $Spin(10)$ GUT model introduces considerations of the non-trivial topology of the vacuum manifold. The $D$-parity of low energy unification…
We analyze the construction of non-supersymmetric three generation six-stack Pati-Salam (PS) $SU(4)_C \times SU(2)_L \times SU(2)_R$ GUT classes of models, by localizing D6-branes intersecting at angles in four dimensional orientifolded…
It is well known that D-brane instantons can generate contributions to the effective superpotential of gauge theories living on D-branes which are perturbatively forbidden by global U(1) symmetries. We extend this idea to theories with…
We discuss the phenomenology of a toy intersecting brane model where supersymmetry is dynamically broken in an open string hidden sector and gauge-mediated to the visible sector. Scalar masses ~ TeV are easily realizable, and R-symmetry is…
We present a geometric argument for the transformation properties of SU(5) --> S(U(3) x U(2)) monopoles under the residual gauge symmetry. This strongly supports the proposal that monopoles of the dual standard model interact via a gauge…
Our contribution sets out to investigate the phenomenology of a gauge model based on an $SU_{L}(2) \times U_{R}(1)_{J} \times U(1)_{K}$-symmetry group. The model can accommodate in its distinct phases - by virtue of different…