4-DIMENSIONAL BLACK-HOLES IN STRING THEORY

Exact solutions of heterotic string theory corresponding to four-dimen sional charge Q magnetic black holes are constructed as tenser product s of an SU(2)/Z(2Q+2) WZW orbifold with a (0,1) supersymmetric SU(1,1) /U(1) WZW coset model. The spectrum is analyzed in some detail. ''Bad' ' marginal operators are found which are argued to deform these theori es to asymptotically fiat black holes. Surprising behavior is found fo r small values of Q, where low-energy field theory is inapplicable. At the minimal value Q = 1, the theory degenerates. Renormalization-grou p arguments are given that suggest the potential gravitational singula rity of the low-energy field theory is resolved by a massive two-dimen sional field theory. At (Q = 0, a stable, neutral ''remnant,'' of pote ntial relevance to the black hole information paradox, is found.