Effective field theories (EFTs) are playing a prominent role in the search for new physics (NP), being used to parametrize possible deviations away from the SM. One must also use EFTs in order to calculate contributions to low-energy precision observables in models with high-scale NP. In such situations, the NP model should be matched onto an appropriate EFT (often the SMEFT). In this seminar I will discuss the how and the why of EFT matching and share new developments related to the efficient calculation at multi-loop order. I will also discuss how to extend the modern methods to theories with spontaneously broken gauge symmetries by working with a partially fixed background field gauge.
INFN & DFA - Dott. Luca Vecchi
