EFT matching from analyticity and unitarity of scattering amplitudes
Stefano De Angelis (IPhT, Saclay)

In the first part of the seminar, I will review some recent progress made using modern on-shell techniques to understand (relativistic) EFTs and uncover hidden structures, with a particular focus on the SMEFT (from a purely on-shell construction of EFTs to selection rules in cross-section and RG equations). Motivated by this recent progress, in the second part, I will present a new on-shell formula for the matching of ultraviolet models featuring massive states onto their massless effective field theory. This formula is based on a dispersion relation in the space of complex momentum dilations to capture, in a single variable, the relevant analytic structure of scattering amplitudes at any multiplicity.