Abstract

Recently, a new mechanism to generate a naturally small electroweak scale has been proposed, relying on the cosmological evolution of the Higgs mass parameter rather than new symmetries at the electroweak scale. It exploits the coupling of the Higgs boson to an axionlike field and a long era in the early Universe where the axion unchains a dynamical screening of the Higgs mass. The key feature is that the time evolution is stopped by electroweak symmetry breaking itself, due to the back-reaction of the Higgs vacuum expectation value on the axion potential that necessarily stops its cosmological evolution close to the critical line where electroweak symmetry is unbroken. This self-organized criticality offers a new twist in the long and fruitful history of the interplay between particle physics and cosmology, with dramatic implications for strategies to search for new physics linked to the understanding of the weak scale.