Testing models of inflation with CMB non-gaussianity

TL;DR

This paper compares two models of primordial non-Gaussianity using CMB data, deriving new expressions for their bispectra and estimating their detectability with current and future experiments.

Contribution

It introduces new formulas for the angular bispectra of local and warm inflation models and assesses their observational constraints.

Findings

Standard deviation for f_{WI} estimator is about 5 times larger than for f_{NL}

WMAP data constrains f_{WI} to between -375 and 36.8

Planck could potentially detect signals of f_{WI}

Abstract

Two different predictions for the primordial curvature fluctuation bispectrum are compared through their effects on the Cosmic Microwave Background temperature fluctuations. The first has a local form described by a single parameter f_{NL}. The second is based on a prediction from the warm inflationary scenario, with a different dependence on wavenumber and a parameter f_{WI}. New expressions are obtained for the angular bispectra of the temperature fluctuations and for the estimators used to determine $f_{NL}$ and f_{WI}. The standard deviation of the estimators in an ideal experiment is roughly 5 times larger for f_{WI} than for f_{NL}. Using 3 year WMAP data gives limits -375<f_{WI}<36.8, but there is a possibility of detecting a signal for f_{WI} from the Planck satellite.