Families of exact (0,2) supersymmetric conformal field theories of magnetically and electrically charged extremal 4D black hole solutions of heterotic string theory are presented. They are constructed using a (0,1) supersymmetric SL(2,openR)×SU(2) Weiss-Zumino-Witten model where anomalously embedded U(1)×U(1) subgroups are gauged. Crucial cancellations of the U(1) anomalies coming from the supersymmetric fermions, the current algebra fermions, and the gauging ensure that there is a consistency of these models at the quantum level. Various 2D models, which may be considered as building blocks for extremal 4D constructions, are presented. They generalize the class of 2D models which might be obtained from gauging SL(2,openR) and coincide with known heterotic string backgrounds. The exact conformal field theory presented by Giddings, Polchinski, and Strominger describing the angular sector of the extremal magnetically charged black hole is a special case of this construction. An example where the radial and angular theories are mixed nontrivially is studied in detail, resulting in an extremal dilatonic Taub-NUT-like dyon.

• Received 4 April 1994

DOI:https://doi.org/10.1103/PhysRevD.50.4032