Flat Tree-level Inflationary Potentials in Light of CMB and LSS Data

TL;DR

This paper evaluates flat tree-level inflationary models with radiative corrections and non-renormalizable operators against CMB and LSS data, finding they fit well and predict small tensor perturbations, suggesting they are a standard inflationary class.

Contribution

It introduces and tests a broad class of flat tree-level inflation models with radiative corrections and NROs against observational data, establishing them as a viable and standard inflationary framework.

Findings

Models fit CMB and LSS data with few parameters.

Predict small tensor-to-scalar ratio (r < 10^{-3}).

NRO models can produce significant spectral index running.

Abstract

We use cosmic microwave background and large scale structure data to test a broad and physically well-motivated class of inflationary models: those with flat tree-level potentials (typical in supersymmetry). The non-trivial features of the potential arise from radiative corrections which give a simple logarithmic dependence on the inflaton field, making the models very predictive. We also consider a modified scenario with new physics beyond a certain high-energy cut-off showing up as non-renormalizable operators (NRO) in the inflaton field. We find that both kinds of models fit remarkably well CMB and LSS data, with very few free parameters. Besides, a large part of these models naturally predict a reasonable number of e-folds. A robust feature of these scenarios is the smallness of tensor perturbations (r < 10^{-3}). The NRO case can give a sizeable running of the spectral index while achieving a sufficient number of e-folds. We use Bayesian model comparison tools to assess the relative performance of the models. We believe that these scenarios can be considered as a standard physical class of inflationary models, on a similar footing with monomial potentials.