New black hole, string and membrane solutions of the four-dimensional heterotic string

Abstract We present solutions of the low-energy four-dimensional heterotic string corresponding to p-branes with p=0, 1, 2, which are characterized by a mass per unit p-volume, M p+1 , and topological “magnetic” charge, gp+1. In the extremal limit, √2ϰ M p+1 =g p+1 , they reduce to the recently discovered nonsingular supersymmetric monopole, string and domain wall solutions. A novel feature is that the solutions involve both the dilaton and the modulus fields. In particular, the effective scalar coupling to the Maxwell field, e−αφFμνFμν, gives rise to a new string black hole with α=√3, in contrast to the pure dilaton black hole solution which has α=1. This means that electric/magnetic duality in D=4 may be seen as a consequence of string/fivebrane duality in D=10.