Vacuum Stability, Naturalness and Gravity

by Alberto Salvio (IFAE, Barcelona)

Friday 20 May 2016, 11:30 → 12:30 Europe/Zurich

Room 234 (Geneva University)

Current experimental goals include (1) testing the Standard Model (SM) and (2) discovering new physics at the TeV scale, if any. In this talk we will see some example of how theorists can help on both sides. As far as goal (1) is concerned, high energy extrapolations of the SM can provide tests that are complementary to the LHC experiments: for example, the probable metastability of the SM vacuum may be a problem during inflation. We will also see how well-motivated new physics can stabilize such vacuum. Regarding goal (2), naturalness (of the Higgs mass) could be a useful guide to anticipate new physics at the LHC. We will discuss a recent definition of naturalness that uses only finite quantities. This potentially broadens the class of natural theories, but two challenges have to be addressed: the elimination of the Landau poles and gravity. The latter will lead us to a possibly sensible and predictive theory of quantum gravity, whose features and open problems will be discussed.