$g_{\rm NL}$ in the curvaton model constrained by PLANCK

TL;DR

This paper investigates the curvaton model with polynomial potential, showing it can produce large negative non-Gaussianity parameter g_NL, and discusses constraints from PLANCK data.

Contribution

It extends the mass-term curvaton model to include polynomial potentials, analyzing non-linear dynamics and their impact on g_NL constraints from PLANCK.

Findings

Large negative g_NL can be generated with minimal tuning.

Positive g_NL remains difficult to produce.

PLANCK constraints still allow significant negative g_NL values.

Abstract

As a simplest extension to the mass-term curvaton model, the curvaton model with a polynomial potential can relax the restricted constraint from PLANCK due to the non-linear dynamics of curvaton field before it decays. We find that there is still a big room for producing a large negative $g_{\rm NL}$, but not positive $g_{\rm NL}$. For example, we only need around 10% "tuning" for $-g_{\rm NL}>10^4$.