Viable Curvaton Models from the $f_{NL}$ Parameter

TL;DR

This paper develops a curvaton inflationary model that accounts for scale-dependent non-Gaussianities, particularly the sign change of the $f_{NL}$ parameter, and explores observational constraints including hemispherical asymmetry.

Contribution

It introduces a method to construct curvaton models with specific $f_{NL}$ scale dependence and provides a concrete example linking theoretical predictions with observational constraints.

Findings

The $f_{NL}$ parameter can change sign at a specific scale.

A procedure to recover curvaton models matching desired $f_{NL}$ behavior.

Hemispherical asymmetry offers additional constraints on the model.

Abstract

We show how to build a curvaton inflationary model motivated by scale-dependent non-Gaussianities of cosmological perturbations. In particular, we study the change of sign in the $f_{NL}$ parameter as a function of the curvaton field value at horizon crossing and identify it with the cosmic microwave background pivot scale. We devise a procedure to recover the curvaton model that provides the desired $f_{NL}$ parameter. We then present a concrete example of $f_{NL}$ and construct its parent model. We study the constraints applied to this model based on considerations taken on $f_{NL}$. We show that the hemispherical asymmetry can also be used to constrain the scale-dependence of $f_{NL}$ and the model parameters.