EW vacuum stability and sensitivity to Planck scale physics

by Vincenzo Branchina (Università di Catania)

Thursday 26 Feb 2015, 16:00 → 17:30 Europe/Rome

Aula Careri (Dipartimento di Fisica - Ed. G. Marconi)

For the present experimental values of the Higgs and top masses, the Higgs effective potential becomes unstable at a scale of about $10^10$ GeV. For this reason, it is widely believed that if new physics shows up only at very high energy scales (Planck scale), this should have no impact on the stability condition of the EW vacuum. It has been recently shown, however, that new physics interactions can strongly affect the vacuum stability condition, so that the stability diagram of the Standard Model can be very different from the diagram (obtained ignoring new physics) that is usually presented. This has far reaching theoretical and phenomenological consequences. In particular, despite claims to the contrary, higher precision measurements of the top and Higgs masses will not provide any definite answer on the fate of our universe, i.e. they will not tell us whether we live in a stable or metastable vacuum state, or at the edge of stability (as often stated).