A Model of Asymmetric Orbifold with D-Branes

Abstract

We consider an orientifold model of IIB string compactified on a six-dimensional torus on the basis of an asymmetric orbifold. A careful study of the T-duality group shows that there exists a discrete Z3 × Z3 symmetry that acts on the string worldsheet asymmetrically by choosing an appropriate configuration of T . This torus is nonfactorizable and has a metric proportional to the Cartan matrix of the E6 group. The open string sector is constructed from D9-branes with some magnetic fluxes turned on along T 6 in such a way that the Dbrane system is consistent with Z3 × Z3. By solving the RR-tadpole condition, we obtain a consistent string model with a gauge group SO(4).