Otero Camaño, XiánEdelstein Glaubach, José DanielMaldacena, JuanZhiboedov, Alexander2018-01-122018-01-122016-02-03Camanho, X.O., Edelstein, J.D., Maldacena, J. et al. J. High Energ. Phys. (2016) 2016: 20. https://doi.org/10.1007/JHEP02(2016)020http://hdl.handle.net/10347/16317We consider higher derivative corrections to the graviton three-point coupling within a weakly coupled theory of gravity. Lorentz invariance allows further structures beyond the one present in the Einstein theory. We argue that these are constrained by causality. We devise a thought experiment involving a high energy scattering process which leads to causality violation if the graviton three-point vertex contains the additional structures. This violation cannot be fixed by adding conventional particles with spins J ≤ 2. But, it can be fixed by adding an infinite tower of extra massive particles with higher spins, J > 2. In AdS theories this implies a constraint on the conformal anomaly coefficients a−c c . 1 ∆2 gap in terms of ∆gap, the dimension of the lightest single trace operator with spin J > 2. For inflation, or de Sitter-like solutions, it indicates the existence of massive higher spin particles if the gravity wave non-gaussianity deviates significantly from the one computed in the Einstein theoryeng© The Author(s) 2016. This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are creditedhttp://creativecommons.org/licenses/by/4.0/AdS-CFT CorrespondenceModels of Quantum GravityClassical Theories of Gravityjournal article10.1007/JHEP02(2016)0201029-8479open access