Light inflaton completing Higgs inflation

TL;DR

This paper proposes a Standard Model extension with a light inflaton that resolves unitarity and vacuum stability issues in Higgs inflation, linking inflationary observables with unitarity scale.

Contribution

It introduces a model with a linear non-minimal coupling that restores unitarity up to the Planck scale and connects inflationary predictions with particle physics.

Findings

Unitarity is maintained up to the Planck scale.

The model addresses vacuum instability in the Standard Model.

Inflationary observables are correlated with the unitarity scale.

Abstract

We consider the extension of the Standard Model (SM) with a light inflaton where both unitarity problem in Higgs inflation and vacuum instability problem are resolved. The linear non-minimal coupling of the inflaton to gravity leads to a significant kinetic mixing between the inflaton and the graviton such that perturbative unitarity is restored up to Planck scale. We show the correlation between unitarity scale and inflationary observables in this model and discuss how the effective Higgs inflation appears.