Generation of scale invariant density perturbations in a conformally invariant Inert Higgs doublet model

TL;DR

This paper demonstrates that a conformally coupled inert Higgs doublet can generate scale-invariant density perturbations in the early universe, linking cosmological observations with Higgs sector properties.

Contribution

It introduces a realistic inert Higgs doublet model with conformal coupling to gravity that produces scale-invariant perturbations and constrains scalar potential couplings from CMB data.

Findings

Perturbations of inert Higgs are scale invariant.

Model predicts Higgs and scalar masses consistent with CMB data.

Loop corrections induce electroweak symmetry breaking.

Abstract

If a Higgs field is conformally coupled to gravity, then it can give rise to the scale invariant density perturbations. We make use of this result in a realistic inert Higgs doublet model, where we have a pair of Higgs doublets conformally coupled to the gravity in the early universe. The perturbation of the inert Higgs is shown to be the scale invariant. This gives rise to the density perturbation observed through CMB by its couplings to the standard model Higgs and the subsequent decay. Loop corrections of this conformally coupled system gives rise to electroweak symmetry breaking. We constrain the couplings of the scalar potential by comparing with the amplitude and spectrum of CMB anisotropy measured by WMAP and this model leads to a prediction for the masses of the lightest Higgs and the other scalars.