Stabilizing the Higgs potential with a Z$'$

Understand

Current data point toward metastability of the electroweak vacuum within the Standard Model.

• We study the possibility of stabilizing the Higgs potential in U(1) extensions thereof.
• A generic Z$'$ boson improves stability of the scalar potential in two ways: it increases the Higgs self--coupling, due to a positive contribution to the beta--function of the latter, and it decreases the top quark Yukawa coupling, which again has a stabilizing effect.
• We determine the range of U(1) charges which leads to a stable electroweak vacuum.