Related papers: RR photons
Intersecting branes have been the subject of string model building for several years. This work introduces in detail the toroidal and Z_N-orientifolds, where the main discussion employs the picture of intersecting D6-branes. The derivation…
We argue for the existence of additional constraints on SU(2) gauge theories in four dimensions when realized in ultraviolet completions admitting an analog of D-brane nucleation. In type II string compactifications these constraints are…
We review cosmological solutions of type II superstrings and M-theory, emphasizing the role of non-vanishing Ramond form backgrounds. Compactifications on flat and, more generally, maximally symmetric spatial subspaces are presented. We…
In the case of F-theory compactifications on genus-one fibrations without section there are naturally appearing discrete symmetries, which we argue to be associated to geometrically massive U(1) gauge symmetries. These discrete symmetries…
Present experiments are sensitive to very weakly coupled extra gauge symmetries which motivates further investigation of their appearance in string theory compactifications and subsequent properties. We consider extensions of the standard…
We study axion-photon couplings in compactifications of type IIB string theory. We find that these couplings are systematically suppressed compared to the inverse axion periodicity, as a result of two effects. First, couplings to the QED…
We construct intersecting D-brane configurations that encode the gauge groups and field content of dual N=4 supersymmetric gauge theories in three dimensions. The duality which exchanges the Coulomb and Higgs branches and the…
We study gauge theories where quasi-hidden sectors are added to the MSSM for the sake of string consistency conditions which would otherwise not be satisfied. We focus on quiver gauge theories motivated by weakly coupled type II orientifold…
Combining the benefits of D-branes and background fluxes in string compactifications opens up the possibility to explore phenomenologically interesting brane world models with stabilized moduli. However, it is difficult to determine…
Using U-duality, the properties of the matrix theories corresponding to the compactification of M-theory on $T^d$ are investigated. The couplings of the $d+1$ dimensional effective Super-Yang-Mills theory to all the M-theory moduli is…
We review a progress in obtaining the complete non-perturbative effective action of type II string theory compactified on a Calabi-Yau manifold. This problem is equivalent to understanding quantum corrections to the metric on the…
We demonstrate that M-theory compactifications on 7-manifolds of G_2 holonomy, which yield 4d N=1 supersymmetric systems, often admit at special loci in their moduli space a description as type IIA orientifolds. In this way, we are able to…
We study kinetic mixing between massless U(1)s in toroidal orbifolds with D3-branes at orbifold singularities. We focus in particular on C^3/Z_4 singularities but also study C^3/Z_6 and C^3/Z'_6 singularities. We find kinetic mixing can be…
We study D-brane inspired models with U(3) x U(2) x U(1)^N gauge symmetry in the context of split supersymmetry. We consider configurations with one, two and three (N=1,2,3) abelian branes and derive all hypercharge embeddings which imply a…
We embed the large N Chern-Simons/topological string duality in ordinary superstrings. This corresponds to a large $N$ duality between generalized gauge systems with N=1 supersymmetry in 4 dimensions and superstrings propagating on…
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 determine the spectrum of D-string bound states in various classes of generalized type I vacuum configurations with sixteen and eight supercharges. The precise matching of the BPS spectra confirms the duality between unconventional type…
In the presence of internal magnetic fields, a D9 brane can acquire a D5 (or anti-D5) R-R charge, and can therefore contribute to the corresponding tadpole. In the resulting vacua, supersymmetry is generically broken and tachyonic…
We consider compactifications of M-theory and type IIA string theory to four dimensions. For Minkowski space-time, a supergravity no-go theorem forbids flux supported in the internal space. We show how to evade this no-go theorem by…
Recently a class of Type IIA orientifold models was constructed yielding just the fermions of the SM at the intersections of D6-branes wrapping a 6-torus. We generalize that construction to the case of Type IIB compactified on an…