Running inflation with unitary Higgs

TL;DR

This paper explores a unitarized Higgs inflation model with a sigma scalar, demonstrating that loop corrections align the inflationary predictions with observational data, while also improving vacuum stability.

Contribution

It introduces a sigma-model type scalar to unitarize Higgs inflation, enhancing vacuum stability and matching inflationary predictions with observational data.

Findings

Loop-corrected spectral index consistent with Planck data

Tensor-to-scalar ratio within observational bounds

Model improves Standard Model vacuum stability

Abstract

We consider the renormalization group(RG) improved inflaton potential in unitarized Higgs inflation where the original Higgs inflation is unitarized by the addition of a real singlet scalar of sigma-model type. The sigma field coupling to the Higgs, which is introduced to reproduce a large non-minimal coupling of the Higgs below the sigma scalar threshold, also improves the Standard Model vacuum stability due to the RG running. Furthermore, the same sigma field coupling determines the reheating temperature or the number of efoldings. Considering the uncertainties in the number of efoldings in the model, we show that the loop-corrected spectral index and tensor-to-scalar ratio are consistent with nine-year WMAP and new Planck data within 1sigma.