Dynamics of extreme black holes and massive string states

In a recent paper, Duff and Rahmfeld argued that certain massive ${\mathit{N}}_{\mathit{R}}$=1/2 states of the four-dimensional heterotic string correspond to extreme black hole solutions. We provide further, dynamical, evidence for this identification by comparing the scattering of these elementary string states with that of the corresponding extreme black holes, in the limit of low velocities. © 1995 The American Physical Society.