CMB anomalies and the effects of local features of the inflaton potential

TL;DR

This paper investigates how local features in the inflaton potential can explain specific anomalies in the primordial spectrum observed in CMB data, improving the fit over featureless models.

Contribution

It is the first analysis to examine the impact of local inflaton potential features on CMB anomalies, providing a new approach to understanding primordial perturbations.

Findings

Local features improve fit to CMB data

Features mainly affect the bump region in the spectrum

Spectrum unaffected on other scales

Abstract

Recent analysis of the WMAP and Planck data have shown the presence of a dip and a bump in the spectrum of primordial perturbations at the scales $k=0.002$ Mpc${}^{-1}$ and $k=0.0035$ Mpc${}^{-1}$ respectively. We analyze for the first time the effects a local feature in the inflaton potential to explain the observed deviations from scale invariance in the primordial spectrum. We perform a best fit analysis of the cosmic microwave background (CMB) radiation temperature and polarization data. The effects of the features can improve the agreement with observational data respect to the featureless model. The best fit local feature affects the primordial curvature spectrum mainly in the region of the bump, leaving the spectrum unaffected on other scales.