New physics and stability of the electroweak vacuum

Titolo: New physics and stability of the electroweak vacuum

Relatore: Prof. Vincenzo Branchina (Dip. di Fisica e INFN Catania)

ABSTRACT: When the stability analysis of the electroweak (EW) vacuum is performed, it turns out that, depending on the values of the Higgs and top masses (M_H and M_t), the EW vacuum is stable, metastable or unstable. In this framework, the Standard Model (SM) is considered to be valid up to the Planck scale M_P : new physics shows up at M_P. However, the analysis is done by assuming that these new physics interactions have no impact on the stability condition of the EW vacuum. Therefore, they are ignored. I will show that, contrary to this expectation, new physics can strongly affect the vacuum stability condition. As a consequence, the stability diagram of the SM can be very different from the well known diagram that results from the usual analysis. This is mainly due to the non-perturbative nature of tunnelling and has far reaching theoretical and phenomenological consequences. In particular, contrary to recent claims, higher precision measurements of M_t (and M_H) cannot provide any definite answer on the stability condition of the EW vacuum.

Persona di contatto:Colangelo

Relatore:Prof. Vincenzo Branchina