# The running of featureful primordial power spectra

## TL;DR

This paper explores how localized features in primordial power spectra could explain observed anomalies in CMB data, and discusses how future measurements can distinguish between featureless and featureful spectra, testing the slow-roll inflation paradigm.

## Contribution

It demonstrates that localized features in primordial spectra can mimic slow-roll anomalies and assesses the potential of future CMB data to differentiate between these models.

## Key findings

- Mock Planck data shows weak evidence against featureful spectra.
- Upcoming CMB measurements could strongly favor featureless spectra.
- Localized features can mimic slow-roll anomalies in current data.

## Abstract

Current measurements of the temperature and polarization anisotropy power spectra of the Cosmic Microwave Background (CMB) seem to indicate that the naive expectation for the slow-roll hierarchy within the most simple inflationary paradigm may not be respected in nature. We show that a primordial power spectra with localized features could in principle give rise to the observed slow-roll anarchy when fitted to a featureless power spectrum. Future CMB missions have the key to disentangle among the two possible paradigms and firmly establish the slow-roll mechanism as the responsible one for the inflationary period in the early universe. From a model comparison perspective, and assuming that nature has chosen a featureless primordial power spectrum, we find that, while with mock Planck data there is only weak evidence against a model with localized features, upcoming CMB measurements may provide strong evidence against such a non-standard primordial power spectrum.