Trispectrum estimation in various models of equilateral type non-Gaussianity

TL;DR

This paper compares the shapes of trispectra in various equilateral non-Gaussian inflation models, introduces an estimator for trispectrum amplitude, and constrains model parameters using WMAP5 data.

Contribution

It provides a detailed shape correlation analysis of trispectra across multiple models and introduces a new estimator for trispectrum amplitude.

Findings

Most models are distinguishable based on trispectrum shape correlations.

The estimator $g_{NL}^{equil}$ relates trispectrum amplitude to model parameters.

WMAP5 data constrains the amplitude and parameters of these models.

Abstract

We calculate the shape correlations between trispectra in various equilateral non-Gaussian models, including DBI inflation, ghost inflation and Lifshitz scalars, using the full trispectrum as well as the reduced trispectum. We find that most theoretical models are distinguishable from the shapes of primordial trispectra except for several exceptions where it is difficult to discriminate between the models, such as single field DBI inflation and a Lifshitz scalar model. We introduce an estimator for the amplitude of the trispectrum, $g_{\rm NL} ^{equil}$ and relate it to model parameters in various models. Using constraints on $g_{\rm NL} ^{equil}$ from WMAP5, we give constraints on the model parameters.