Natural Relaxation

TL;DR

This paper introduces a natural relaxation mechanism in inflationary cosmology that explains the electroweak-Planck scale hierarchy, predicts vacuum metastability, and connects to neutrino physics and dark matter extensions.

Contribution

It proposes a novel relaxation scenario consistent with inflation that addresses hierarchy, vacuum stability, and neutrino mass generation within a unified framework.

Findings

Predicts near-criticality and metastability of the Higgs vacuum

Provides a viable reheating channel via Majorana neutrinos

Suggests dark matter extensions could solve vacuum stability issues

Abstract

Motivated by natural inflation, we propose a relaxation mechanism consistent with inflationary cosmology that explains the hierarchy between the electroweak scale and Planck scale. This scenario is based on a selection mechanism that identifies the low scale dynamics as the one that is screened from UV physics. The scenario also predicts the near-criticality and metastability of the standard model vacuum state, explaining the Higgs boson mass observed at the LHC. Once Majorana right-handed neutrinos are introduced to provide a viable reheating channel, our framework yields a corresponding mass scale that allows for the seesaw mechanism as well as for standard thermal leptogenesis. We argue that considering singlet scalar dark matter extensions of the proposed scenario could solve the vacuum stability problem and discuss how the cosmological constant problem is possibly addressed.