A Bayesian analysis of inflationary primordial spectrum models using Planck data

TL;DR

This paper uses Bayesian analysis to compare inflationary primordial spectrum models with Planck CMB data, finding the standard power-law model is preferred over models with features like cutoffs, highlighting the need for alternative explanations for low large-scale power.

Contribution

It provides a Bayesian model comparison of cutoff inflationary primordial spectra against Planck data, showing the standard power-law model's preference.

Findings

Standard power-law model is preferred over cutoff models

Models with features do not improve fit to Planck data

Highlights the need for alternative explanations for large-scale CMB anomalies

Abstract

The current available CMB data show an anomalously low value of the CMB temperature fluctuations at large angular scales (l < 40). This lack of power is not explained by the minimal LCDM model, and one of the possible mechanisms explored in the literature to address this problem is the presence of features in the primordial power spectrum (PPS) motivated by the early universe physics. In this paper, we analyse a set of cutoff inflationary PPS models using a Bayesian model comparison approach in light of the latest Cosmic Microwave Background (CMB) data from the Planck Collaboration. Our results show that the standard power-law parameterisation is preferred over all models considered in the analysis, which motivates the search for alternative explanations for the observed lack of power in the CMB anisotropy spectrum.