Non-Gaussianity and Gravitational Waves from Quadratic and Self-interacting Curvaton

TL;DR

This paper explores how non-Gaussianity and gravitational wave measurements can constrain parameters of the curvaton model, including effects of self-interactions, to better understand the origin of cosmic structure.

Contribution

It demonstrates how measurements of non-Gaussianity and gravitational waves can determine curvaton parameters and analyzes the impact of self-interactions on these predictions.

Findings

Measurement of fNL and tensor-to-scalar ratio constrains curvaton parameters.

Self-interactions modify non-Gaussianity predictions.

Additional data can constrain curvaton interactions.

Abstract

In this paper we consider how non-Gaussianity of the primordial density perturbation and the amplitude of gravitational waves from inflation can be used to determine parameters of the curvaton scenario for the origin of structure. We show that in the simplest quadratic model, where the curvaton evolves as a free scalar field, measurement of the bispectrum relative to the power spectrum, fNL, and the tensor-to-scalar ratio can determine both the expectation value of the curvaton field during inflation and its dimensionless decay rate relative to the curvaton mass. We show how these predictions are altered by the introduction of self-interactions, in models where higher-order corrections are determined by a characteristic mass scale and discuss how additional information about primordial non-Gaussianity and scale dependence may constrain curvaton interactions.