Particle Theory Seminars

The particle theory seminars are organized by the Theory Group of the Laboratory for Particle Physics (LTP) at PSI.

The next seminar takes place on Thursday, 4.7.2024, at 11:15 in OSGA/EG6b

Speaker:  Anders Eller Thomsen (ITP, AEC, University of Bern)

Title: Gauge-Fixing in EFT Matching Calculations

Abstract

EFT matching for new physics beyond the SM relies on a partial cancellation between loops in the EFT and loops in the UV model. A proof of this cancellation has been established in non-gauge theories; however, the proof does not immediately generalize to theories with gauge symmetries such as might be found in realistic BSM models. I will discuss how to complete the proof for gauge theories using the background field gauge, showing that the usual methods are valid. The results do not seem to generalize to situations involving spontaneous symmetry breaking, potentially posing a calculational challenge in such scenario. As a remedy to this issue, I present a partially fixed background field gauge exhibiting the desired cancellation between UV and EFT loops.