Particle Seminar

Monday, October 5, 2020

Speaker: Alessandro Ugolotti

Affiliation: Friedrich-Schiller-Universit├Ąt Jena

Time: 2:30PM -- 3:30PM

Location: Virtual seminar on zoom

Title: A new fresh look at asymptotic freedom for gauged-Yukawa models


The discovery in 1973 that non-Abelian gauge theories are asymptotically free was the missing tail towards the final description of the Standard Model as a Quantum Field Theory based on a local gauge symmetry. Indeed, the electroweak and strong interactions are both described by gauge theories where the gauge bosons are the mediators of the interactions. Neglecting the hypercharge group, the renormalization group flow of the Standard Model resembles an asymptotically free trajectory. This result, based on standard perturbation theory, is usually obtained by computing the beta functions in the deep Euclidean regime, where all mass-threshold effects are neglected with respect to the quantum fluctuations. However, this assumption may be restrictive and hide possible ultraviolet completions of the Standard Model. In this talk, I will try to convince you that, by using suitable (non)-perturbative methods which take mass-threshold effects properly into account, it is possible to unveil novel asymptotically free trajectories for the non-Abelian subsector of the Standard Model. This new perspective might be a guiding principle to solve the triviality problem which arises as soon as the abelian hypercharge gauge group of the Standard Model is included.