Strings on eight-orbifolds

We present several examples of T-8/P orbifolds with P subset of SU4. We compute their Hodge numbers and consider turning on discrete torsion. We then study supersymmetric compactifications of type II, heterotic, and type I strings on these orbifolds. Heterotic compactifications to D = 2 have a B-field tadpole with coefficient given by that of the anomaly polynomial. In the SO32 heterotic with standard embedding the tadpole is absent provided the internal space has a precise value of the Euler number. Guided by their relation to type I, we find tadpole-free SO32 heterotic orbifolds with non-standard embedding. (C) 2004 Elsevier B.V. All rights reserved.