Partial non-renormalisation of the stress-tensor four-point function in N=4 SYM and AdS/CFT

We show that, although the correlator of four stress-tensor multiplets in N = 4 SYM is known to have radiative corrections, certain linear combination s of its components are protected from perturbative renormalisation and rem ain at their free-field values. This result is valid for weak as well as fo r strong coupling and for any gauge group. Our argument uses Intriligator's insertion formula, and includes a proof that the possible contact term con tributions cannot change the form of the amplitudes. Combining this new non-renormalisation theorem with Maldacena's conjecture allows us to make a prediction for the structure of the corresponding corre lator in AdS supergravity. This is verified by first considerably simplifyi ng the strong coupling expression obtained by recent supergravity calculati ons, and then showing that it does indeed exhibit the expected structure. ( C) 2001 Elsevier Science B.V. All rights reserved.