Characterizing the EFT-hedron

High-energy physics can be encoded into low-energy effective field theories (EFTs) as an infinite set of Wilson coefficients. Requiring that the high-energy theory respects the fundamental physical principles of unitarity, locality, and causality bounds the values of these coefficients for 2->2 scattering amplitudes to live inside of a positive geometry in the space of Wilson coefficients known as the “EFT-hedron.” As constraints on an increasing number of Wilson coefficients are considered, the EFT-hedron has several surprising features that I will describe in my talk. I will additionally explain how requiring that Wilson coefficients live inside the EFT-hedron can place new constraints on what physics is allowed at high energies.