Bulk physics at a graviton factory

A general prediction of the 5-d Randall-Sundrum (RS) hierarchy model is the emergence of spin-2 Kaluza-Klein (KK) gravitons with weak scale masses and couplings. The lowest order L effective theory of the RS model is given by 5-d Einstein gravity which uniquely fixes the self-interactions of gravito ns. We demonstrate that large numbers of light KK resonances could be produ ced at a future lepton-collider-based "Graviton Factory". Measuring the sel f-interactions of these KK gravitons will probe the accuracy of the 5-d Ein stein gravity picture and, in addition, yield indirect information on the a s yet untested self-coupling of the 4-d graviton. The self-interactions of the gravitons can be studied by measuring the decays of the heavier states to the lighter ones. Using the AdS/CFT picture, these can be interpreted as the decays of heavier resonances to lighter ones, in a strongly coupled 4- d CFT. We show that these decays have sufficient rates to be studied at fut ure colliders and that they are also, in principle, sensitive to higher der ivative operators, such as the Gauss-Bonnet term. In a generalized RS model , with non-universal 5-d fermion masses, FCNC's will be induced. We show th at precise measurements of the rare decays of KK graviton/gauge states into flavor non-diagonal final states at a Graviton Factory can be used to map the 5-d fermion mass matrix. (C) 2001 Published by Elsevier Science B.V.