Séminaires, soutenances

Regularization, renormalization or why the standard model can be quite natural

by Jean-François Mathiot (LPC)

Europe/Paris
amphi recherche ()

amphi recherche

Description

The accurate calculation of physical observables in the Standard Model, within the general framework of local quantum field theory, necessitates to control in a strict way quantum corrections beyond tree level contributions. These corrections have generated numerous interrogations as far as the validity of the Standard Model in a  large energy domain is concerned. This refers to the question whether the Standard Model is natural or not.  From the clear distinction of the two different arbitrary scales associated to the regularization procedure and to the physical renormalization of the bare parameters respectively, we reexamine several drawbacks attributed to the Standard Model. We first disentangle the so-called fine-tuning of the Higgs mass coming from quadratic divergences from the hierarchy problem associated to the contribution of super heavy degrees of freedom. These problems disappear once one realizes that the regularization scale should not be confused with any physical variable. This is also the case for the interpretation of the Landau pole, or the validity (the so-called triviality) of the scalar theory giving rise to the Higgs potential.

This seminar is intended for a large audience, with no complicated equations!