Getting to the top with extra dimensions

The prospect of large extra dimensions and an effective theory of gravity a t around a TeV has interesting experimental consequences. In these models, the Kaluza-Klein modes interact with Standard Model particles and these int eractions lead to testable predictions at present and planned colliders. We investigate the effect of virtual exchanges of the spin-2 Kaluza-Klein mod es in the production cross-section of <(tt)over bar> pairs at the Tevatron and the LHC and find that the <(tt)over bar> cross-section can be an effect ive probe of the large extra dimensions. This enables us to put bounds on t he effective low-energy scale. (C) 1999 Published by Elsevier Science B.V. All rights reserved.