English

Comments on Orientifolds without Vector Structure

High Energy Physics - Theory 2009-10-07 v1

Abstract

We revisit type I compactifications with a Spin(32)/Z2 gauge bundle that admits no vector structure. We elucidate the relation of this Z2 obstruction to discrete B-field flux and to 't Hooft flux and clarify some subtleties in the T-duality transformation to type IIA intersecting D-brane models. We reexamine the earliest 3-generation GUT model on magnetized D-branes and show its consistency when a discrete B-flux is switched on. We further generalize partially known results for toroidal models to type I compactifications without vector structure and their mirror dual type IIA orientifolds on genuine Calabi-Yau manifolds. We illustrate this by working out the example of the quintic in some detail.

Keywords

Cite

@article{arxiv.0805.3696,
  title  = {Comments on Orientifolds without Vector Structure},
  author = {Constantin Bachas and Massimo Bianchi and Ralph Blumenhagen and Dieter Lust and Timo Weigand},
  journal= {arXiv preprint arXiv:0805.3696},
  year   = {2009}
}

Comments

34 pages, 3 figures, 1 table

R2 v1 2026-06-21T10:43:41.198Z