Ultraviolet Sensitivity in Higgs-Starobinsky Inflation

TL;DR

This paper examines how higher-dimensional operators affect Higgs-Starobinsky inflation, finding that suppression scales near the Planck scale are necessary to maintain successful inflationary predictions.

Contribution

It analyzes the impact of dimension-six operators on Higgs-Starobinsky inflation and determines the required suppression scales for preserving inflationary viability.

Findings

Suppression scale for scalar Ricci operators must be near the Planck scale.

Other dimension-six operators can have lower suppression scales.

Inflation predictions remain stable if these operators are sufficiently suppressed.

Abstract

The general scalar-tensor theory that includes all the dimension-four terms has parameter regions that can produce successful inflation consistent with cosmological observations. This theory is in fact the same as the Higgs-Starobinsky inflation, when the scalar is identified with the Standard Model Higgs boson. We consider possible dimension-six operators constructed from non-derivative terms of the scalar field and the Ricci scalar as perturbations. We investigate how much suppression is required for these operators to avoid disrupting the successful inflationary predictions. To ensure viable cosmological predictions, the suppression scale for the sixth power of the scalar should be as high as the Planck scale. For the other terms, much smaller scales are sufficient.