Speaker
Description
It is widely appreciated that the electroweak vacuum of Standard Model
resides in a region of metastability. We discuss how absolute stability is
achieved in extensions by a real scalar singlet. Using the renormalisation
group running of couplings, we identify the parameter region for stability
up to the Planck scale, mediated by the Higgs-portal interaction.
Higgs-singlet mixing connects this improved UV behaviour to low-energy
observables. In particular, modifications of the Higgs trilinear self-coupling
can be significantly larger than those of the Higgs-Z coupling, making
Higgs-potential measurements a sensitive probe for the high-scale fate
of the vacuum. We place these results in the broader context of parameter
space compatible with a strong first-order electroweak phase transition and
discuss how precision Higgs measurements and direct searches at current
and future colliders can probe Planck-safe singlet extensions.