3-point functions of universal scalars in maximal SCFTs at large N

We compute all 3-point functions of the ``universal'' scalar operators contained in the interacting, maximally supersymmetric CFTs at large N by using the AdS/CFT correspondence. These SCFTs are related to the low energy description of M5, M2 and D3 branes, and the common set of universal scalars corresponds through the AdS/CFT relation to the fluctuations of the metric and the magnetic potential along the internal manifold. For the interacting (0,2) SCFT_6 at large N, which is related to M5 branes, this set of scalars is complete, while additional non-universal scalar operators are present in the d=4, N=4 super Yang-Mills theory and in the N=8 SCFT_3, related to D3 and M2 branes, respectively.