We study graviton scattering on AdS4βΓS7, which is dual to the
stress tensor multiplet four-point function in the maximally supersymmetric 3d
U(N)1βΓU(N)β1β ABJM theory. We compute 1-loop corrections to this
holographic correlator coming from Witten diagrams with supergravity R and
higher derivative R4 vertices, up to contact term ambiguities, and find that
the flat space limit matches the corresponding terms in the 11d M-theory
S-matrix. We then use supersymmetric localization to show that all the 1-loop
contact terms vanish, as was previously observed for the AdS4βΓS7/Z2β theory dual to U(N)2βΓU(N)β2β ABJM. Finally, we use
the recent localization results of Gaiotto and Abajian, as inspired by twisted
M-theory, to compute all the short OPE coefficients in correlators of the
stress tensor multiplet and the next lowest half-BPS operator, which we find
saturate the bootstrap bounds on these mixed correlators for all N.Comment: 20 pages, 2 figures, sequel to arXiv:2107.1027