Following a recent conjecture by Lapan, Simons and Strominger, we revisit and discuss an intrinsically heterotic class of conformal field theories, emphasizing their Lagrangian construction as asymmetrically gauged WZW models, which may be useful in several applications to the study of supersymmetric strings and black holes in heterotic and type II string theory compactified on T 6 and K3 × T 2...

A while ago, examples of N=1 vacua in D=6 were constructed as orientifolds of Type IIB string theory compactified on the K3 surface. Among the interesting features of those models was the presence of D5–branes behaving like small instantons, and the appearance of extra tensor multiplets. These are both non–perturbative phenomena from the point of view of Heterotic string theory. Although the or...

We review a systematic construction of N = 1 supersymmetric heterotic string vacua using mirror symmetry. The method provides a large class of explicit solutions for stable, holomorphic vector bundles on Calabi–Yau n-folds Z n in terms of toric geometry. Phenomenologically interesting compactifications as well as non-perturbative dynamics of the heterotic string are discussed within this framew...