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Magnetized Four-Dimensional $Z_2 \times Z_2$ Orientifolds

Marianna Larosa·Gianfranco Pradisi
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Abstract

We study deformations of $Z_2 \times Z_2$ (shift-)orientifolds in four dimensions in the presence of both uniform Abelian internal magnetic fields and quantized NS-NS $B_{ab}$ backgrounds, that are shown to be equivalent to asymmetric shift-orbifold projections. These models are related by $T$-duality to orientifolds with $D$-branes intersecting at angles. As in corresponding six-dimensional examples, $D9$-branes magnetized along two internal directions acquire a charge with respect to the R-R six form, contributing to the tadpole of the orthogonal $D5$-branes (``brane transmutation''). The resulting models exhibit rank reduction of the gauge group and multiple matter families, due both to the quantized $B_{ab}$ and to the background magnetic fields. Moreover, the low-energy spectra are chiral and anomaly free if additional $D5$-branes longitudinal to the magnetized directions are present, and if there are no Ramond-Ramond tadpoles in the corresponding twisted sectors of the undeformed models.

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Marianna Larosa, Gianfranco Pradisi. 2003-10-15. Magnetized Four-Dimensional $Z_2 \times Z_2$ Orientifolds. https://doi.org/10.1016/s0550-3213(03)00551-0

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