Reverse Bootstrapping: IR lessons for UV physics

S-matrix bootstrap and positivity bounds are usually viewed as constraints on low-energy theories imposed by the requirement of a standard UV completion. By considering graviton--photon scattering in the Standard Model, we argue that the low-energy theory can be used to put constraints on the UV behaviour of the gravitational scattering amplitudes.
Comment: Published in PRL. 5 pages + supplementary material and 1 figure