Low-$\ell$ power suppression in punctuated inflation

TL;DR

This paper investigates how punctuated inflation models, inspired by MSSM, can explain the low multipole anomalies in the CMB by fitting Planck and WMAP9 data, showing improved data fit and moderate preference over simple models.

Contribution

It introduces a punctuated inflation scenario with a fast-roll phase that better fits CMB data and constrains model parameters using recent observations.

Findings

Punctuated inflation improves fit to CMB data over simple power law models.

Planck data provides tighter constraints on model parameters.

Punctuated inflation is moderately preferred over simple models with Planck data.

Abstract

Motivated by Planck confirmation of an anomalously low value of the CMB temperature fluctuations up to multipole $\ell<40$, we in this paper try to explain such feature by investigating case of punctuated inflation scenario. This form of inflation potential is inspired by Minimal Super-symmetric Standard Model (MSSM) wherein suppression of curvature perturbation power at large scales is produced by introducing period of fast-roll phase of the inflation sandwiched between two stages of slow-roll phase. We apply Markov Chain Monte Carlo analysis to determine posterior distribution and the best fit values of the model parameters using recent WMAP9 and Planck data. We show that WMAP9 and Planck results are consistent with each other and that with Planck data we obtain tighter constraints for punctuated inflation parameters. We find that punctuated inflation leads to better fit in CMB data compared to simple power law model. The improvement in the fit to the WMAP9 data is $\Delta \chi^2\sim 3.6$ and for Planck the improvement is $\Delta \chi^2\sim 5.4$. We find that $AIC$ does not discriminate between punctuated inflation and simple power law model for WMAP9 data. However, for Planck data we find that punctuated inflation is moderately preferred over a simple power law model.