Related papers: On Discrete Gauge Symmetries in Trinification Mode…
The gauge theory on a set of D3-branes at a toric Calabi-Yau singularity can be encoded in a tiling of the 2-torus denoted dimer diagram (or brane tiling). We use these techniques to describe the effect on the gauge theory of geometric…
Inequivalent standard-like observable sector embeddings in $Z_3$ orbifolds with two discrete Wilson lines, as determined by Casas, Mondragon and Mu\~noz, are completed by examining all possible ways of embedding the hidden sector. The…
Spin foams are candidate state-sum models for transition amplitudes in quantum gravity. An active research subject is to identify the possible divergences of spin foam models, or alternatively to show that models are finite. We will discuss…
Gauge-coupling unification is just as successful in the standard model with six Higgs doublets as it is in the minimal supersymmetric standard model. However, the gauge couplings unify at 10^14 GeV, which yields rapid proton decay in the…
We propose a method for constructing pairs of nonsupersymmetric gauge theories related by S-duality. Starting from a known S-duality of supersymmetric theories realized on the worldvolume of D3 branes in type IIB string theory, a new…
Precision gauge coupling unification is one of the primary quantitative successes of low energy or split supersymmetry. Preserving this success puts severe restrictions on possible matter and gauge sectors that might appear at…
We construct three quasi-supersymmetric $G^3$ GUT models with $S_3$ symmetry and gauge coupling unification from intersecting D6-branes on Type IIA orientifolds. The Standard Model fermions and Higgs doublets can be embedded into the…
We review the construction of chiral four-dimensional compactifications of type IIA string theory with intersecting D6-branes. Such models lead to four-dimensional theories with non-abelian gauge interactions and charged chiral fermions. We…
We analyze behaviour of D3-branes in BGMPZ throat geometry. We show that although single brane has some of the moduli stabilized multi-brane system tends to expand and form a bound state. Such a system loses non-abelian gauge symmetry.
Fractional D6-branes on toroidal orbifold backgrounds are known to be able to accommodate the particle spectrum and gauge group of the Standard Model, but up to now exact results for their low-energy effective action are missing. Here we…
Many models of beyond Standard Model physics connect flavor symmetry with a discrete group. Having this symmetry arise spontaneously from a gauge theory maintains compatibility with quantum gravity and can be used to systematically prevent…
We report on the construction of four dimensional gauged supergravity models that can be interpreted as type IIB orientifold compactification in presence of 3-form fluxes and D3--branes. We mainly address our attention to the symplectic…
We review the stabilisation of complex structure moduli in Type IIA orientifolds, especially on $T^6 / (\mathbb{Z}_2 \times \mathbb{Z}_6^\prime \times \Omega \mathcal{R})$ with discrete torsion, via deformations of $\mathbb{Z}_2 \times…
We examine the supersymmetry of classical D-brane and M-brane configurations and explain the dependence of Killing spinors on coordinates. We find that one half supersymmetry is broken in the bulk and that supersymmetry near the D-brane…
We consider the type I theory compactified on $T^3$. When the D5-brane wraps the $T^3$ it yields a D2-brane in seven dimensions. In the leading approximation the moduli space of vacua of the three dimensional field theory on the brane is…
We construct new three-family ${\cal N}=1$ supersymmetric Pati-Salam models from intersecting D6-branes with original gauge group ${\rm U}(4)_C \times {\rm USp}(2)_L \times {\rm U}(2)_R$ on a Type IIA $\mathbb{T}^6/(\mathbb{Z}_2\times…
We study N=1 supersymmetric four-dimensional solutions of massive Type IIA supergravity with intersecting D6-branes in the presence NS-NS three-form fluxes. We derive N=1 supersymmetry conditions for the D6-brane and flux configurations in…
Intersecting D-brane models seem to be one of the most promising avenues to embed the Standard Model physics within the string context. We review here different aspects of these models. Topics include the question of SUSY and quasi-SUSY in…
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 analyze D-brane states and their central charges on the resolution of C^2/Z_n by using local mirror symmetry. There is a point in the moduli space where all n(n-1)/2 branches of the principal component of the discriminant locus coincide.…