A classification of toroidal orientifold models

Abstract

We develop the general tools for model building with orientifolds, including SS supersymmetry breaking. In this paper, we work out the general formulae of the tadpole conditions for a class of non supersymmetric orientifold models of type IIB string theory compactified on T 6 , based on the general properties of the orientifold group elements. By solving the tadpoles we obtain the general anomaly free massless spectrum.

Gauge thresholds in the presence ofobliquemagnetic fluxes

“…Selecting the terms quadratic in f (and thus in Q) and subtracting the IR (in the open string channel) logarithmically divergent terms responsible for their running, we present general formulae for the one-loop threshold corrections to the gauge couplings [23]. After diagonalization of the magnetic rotation matrices, our formulae look very much the same as in the case of 'parallel' magnetic fields [24] which in turn show some similarity with standard formulae for orbifolds [23,25]. We can thus exploit the available technology in order to write very explicit formulae for the thresholds arising from both N = 2 and N = 1 sectors 3 .…”

A class of non-supersymmetric orientifolds

“…The tadpole cancellation conditions that we have derived apply to all Z N orientifolds with action of the form (55). These include our non-supersymmetric as well as supersymmetric orientifolds considered previously [15,16,17,18,19,20]. Our results apply when the D5branes are located at generic fixed points of θ or some power.…”

“…This is needed to have a consistent 1 2 (1 + Ω P ) projection. Now, it can be shown [20,30] Putting all pieces together we find that for Ω P = Ω, the RR tadpole, conveniently normalized, is given by…”

“…In this work we will explain the general construction of D ≤ 10 examples. In particular, we will derive tadpole cancellation conditions valid in non-supersymmetric as well as in supersymmetric orientifolds studied in the past [15,16,17,18,19,20]. For lower dimensional Dp-branes our results carefully take into account their location in the transverse directions.…”

Scherk–Schwarz breaking and intersecting branes

“…The Kaluza-Klein momenta of the various fields are correspondingly shifted proportionally to their R charges, and modular invariance dictates the extension of this mechanism to the full perturbative spectrum in models of oriented closed strings [44,45,46]. When open strings are present (in a background without fluxes), one has to distinguish between the two cases of Scherk-Schwarz deformations transverse or longitudinal to the world-volume of the branes [47][48][49][50][51][52]. In fact, in the former case the open-string fields do not depend on the coordinates of the extra dimension, and therefore are not affected by the deformation.…”