Stable mass hierarchies and dark matter from hidden sectors in the scale-invariant standard model

TL;DR

The paper tackles how to realize stable, radiatively generated mass hierarchies in a classically scale-invariant framework that remains valid up to the Planck scale $M_{ m Pl}$. It introduces a generic hidden-sector mechanism where SM-singlet scalars communicate symmetry breaking through portal couplings, enabling a hierarchy between the electroweak scale and higher scales via the Coleman–Weinberg mechanism. This approach is instantiated with a two-scalar-singlet model that generates the Planck mass from $iglrace S_1 igrrace$ and the neutrino see-saw scale from $iglrace S_2 igrrace$, while keeping the theory perturbative and compatible with a SM-like Higgs mass window $129~{ m GeV}\lesssim m_h\lesssim 175~{ m GeV}$. The authors further extend the framework to a mirror dark matter sector, yielding unbroken mirror symmetry and dark-matter phenomenology compatible with certain experimental signals, thereby linking Planck, electroweak, and neutrino scales through a natural, radiative mechanism.

Abstract

Scale invariance may be a classical symmetry which is broken radiatively. This provides a simple way to stabilise the scale of electroweak symmetry breaking against radiative corrections. But for such a theory to be fully realistic, it must actually incorporate a hierarchy of scales, including the Planck and the neutrino mass scales in addition to the electroweak scale. The dark matter sector and the physics responsible for baryogenesis may or may not require new scales, depending on the scenario. We develop a generic way of using hidden sectors to construct a technically-natural hierarchy of scales in the framework of classically scale-invariant theories. We then apply the method to generate the Planck mass and to solve the neutrino mass and dark matter problems through what may be termed the "scale-invariant standard model". The model is perturbatively renormalisable for energy scales up to the Planck mass.