Related papers: D=4,N=1, Type IIB Orientifolds
We study four dimensional $Z_2 \times Z_2$ (shift)-orientifolds in presence of internal magnetic fields and NS-NS $B$-field backgrounds, describing in some detail one explicit example with N=1 supersymmetry. These models are related by…
We combine moduli stabilisation and (chiral) model building in a fully consistent global set-up in Type IIB/F-theory. We consider compactifications on Calabi-Yau orientifolds which admit an explicit description in terms of toric geometry.…
We propose CFT descriptions of the D1/D5 system in a class of freely acting Z_2 orbifolds/orientifolds of type IIB theory, with sixteen unbroken supercharges. The CFTs describing D1/D5 systems involve N=(4,4) or N=(4,0) sigma models on…
We discuss flux quantization and moduli stabilization in toroidal type IIB Z_N - or Z_N x Z_M -orientifolds, focusing mainly on their orbifold limits. After presenting a detailed discussion of their moduli spaces and effective actions, we…
Model building with rigid D6-branes on the Type IIA orientifold on T6/Z2xZ6' with discrete torsion is considered. The systematic search for models of particle physics is significantly reduced by proving new symmetries among different…
We construct a novel orientifold of type IIB string theory that breaks all supersymmetries. It is a closed string theory without open sector and it can be understood as a Scherk-Schwarz deformation in which supersymmetry is restored at…
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…
Intersecting stacks of supersymmetric fractional branes on the Z_6' orientifold may be used to construct the supersymmetric Standard Model. If $a,b$ are the stacks that generate the SU(3)_{colour} and SU(2)_L gauge particles, then, in order…
Discrete gauge symmetries in global intersecting D-brane models constrain the exact form of the perturbative as well as non-perturbative superpotential. We derive the complete set of conditions on the existence of discrete Zn gauge…
We discuss the four-dimensional N=1 effective actions of single space-time filling Dp-branes in general Type IIA and Type IIB Calabi-Yau orientifold compactifications. The effective actions depend on an infinite number of normal…
The discrete tensorial charges carried by orientifold planes define n-gerbes in space-time. The simplest way to ensure a consistent string compactification is to require these gerbes to be flat. This results in expressions for the local…
We study examples of chiral four-dimensional IIB orientifolds with Scherk--Schwarz supersymmetry breaking, based on freely acting orbifolds. We construct a new Z3xZ3' model, containing only D9-branes, and rederive from a more geometric…
We discuss type IIB orientifolds with D-branes, and NSNS and RR field strength fluxes, with D-brane sectors leading to open string spectra with non-abelian gauge symmetry and charged chiral fermions. The closed string field strengths…
We explicitly construct A-type orientifolds of supersymmetric Gepner models. In order to reduce the tadpole cancellation conditions to a treatable number we explicitly work out the generic form of the one-loop Klein bottle, annulus and…
We construct several examples of compactification of Type IIB theory on orientifolds and discuss their duals. In six dimensions we obtain models with $N=1$ supersymmetry, multiple tensor multiplets, and different gauge groups. In nine…
String compactifications with non-abelian gauge fields localized on D-branes, with background NSNS and RR 3-form fluxes, and with non-trivial warp factors, can naturally exist within T-dual versions of type I string theory. We develop a…
In this work we study type IIB Calabi-Yau orientifold compactifications in the presence of space-time filling D7-branes and O7-planes. In particular, we conclude that $\alpha'^2 g_s$-corrections to their DBI actions lead to a modification…
We derive D-brane gauge theories for C^3/Z_n x Z_n orbifolds with discrete torsion and study the moduli space of a D-brane at a point. We show that, as suggested in previous work, closed string moduli do not fully resolve the singularity,…
D-branes can end on orbifold planes if the action of the orbifold group includes (-1)^{F_L}. We consider configurations of D-branes ending on such orbifolds and study the low-energy theory on their worldvolume. We apply our results to gauge…
We consider non-compact Z_N orientifold models of type IIB superstring theory with four-dimensional gravity induced on a set of coincident D3-branes. For the models with odd N the contribution to the one-loop renormalization of the Planck…