Nov. 28, 2023 at 2 p.m. in Lorentz room (Staudingerweg 7, 5th floor)

Mathias Becker

Sebastian Schenk

Yong Xu

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.