String scattering in flat space and a scaling limit of Yang-Mills correlators

We use the flat space limit of the AdS/CFT correspondence to derive a simple relation between the 2→2 scattering amplitude of massless string states in type IIB superstring theory on ten-dimensional Minkowski space and a scaling limit of the N=4 super Yang-Mills four-point functions. We conjecture that this relation holds nonperturbatively and at arbitrarily high energy.