Magnetized (Shift-)Orientifolds

TL;DR

This paper investigates four-dimensional $Z_2 imes Z_2$ (shift)-orientifolds with internal magnetic and NS-NS $B$-field backgrounds, revealing gauge group rank reduction, chiral spectra, and anomaly cancellation in models with D-branes.

Contribution

It provides a detailed analysis of magnetized orientifold models with explicit examples, showing how background fields affect gauge groups and matter content, and establishing their relation to intersecting D-brane models via T-duality.

Findings

Models exhibit gauge group rank reduction due to background fields.

Low-energy spectra are chiral and anomaly free with D5-branes.

Explicit example with N=1 supersymmetry demonstrates these effects.

Abstract

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 $T$-duality to orientifolds with $D$-branes intersecting at angles and exhibit, due to the background fields, a rank reduction of the gauge group and multiple matter families. Moreover, the low-energy spectra are chiral and anomaly free if $D5$-branes are present along the magnetized directions.