Higgs pole inflation with loop corrections in light of ACT results

TL;DR

This paper explores how loop corrections in Higgs and PQ pole inflation models can align spectral index predictions with ACT observations, considering Standard Model and singlet scalar contributions.

Contribution

It derives the Coleman-Weinberg potential for inflaton in pole inflation scenarios, analyzing loop correction effects on spectral index and tensor-to-scalar ratio.

Findings

Loop corrections can increase the spectral index to match ACT results.

Positive one-loop beta functions allow for two-loop correction accommodation.

Negative one-loop beta functions require sizable two-loop contributions.

Abstract

We present the Coleman-Weinberg potential for the inflaton in the pole inflation scenarios such as the Higgs pole inflation and the Peccei-Quinn (PQ) pole inflation. The loop corrections stem from the Standard Model particles and extra singlet scalar fields in the former case, making the quartic coupling for the Higgs inflaton modified by the inflaton-dependent power corrections during inflation. We also obtain similar power corrections to the quartic coupling for the PQ inflaton, depending on the realizations of the PQ symmetry in KSVZ and DFSZ models. We show that the loop corrections can shift the spectral index in the pole inflation to a larger value in favor of the ACT results, while being compatible with the bound on the tensor-to-scalar ratio. For a positive one-loop beta function for the inflaton quartic coupling (namely, $b_1>0$), a sub-dominant contribution from the two-loop corrections can be accommodated. On the other hand, if the one-loop beta function for the inflaton coupling is negative (namely, $b_1<0$), we need sizable contributions from two-loops that are larger than the one-loop corrections due to the ACT results.