Non-Gaussianity from two right-handed sneutrino curvaton decays

TL;DR

This paper investigates the effects of two right-handed sneutrino curvaton decays on the early universe, highlighting differences from single-curvaton models and potential for large non-Gaussianity.

Contribution

It introduces a detailed analysis of two-curvaton decay scenarios, revealing parameter space conditions and non-Gaussianity outcomes not seen in single-curvaton models.

Findings

One Yukawa coupling can be as large as 0.1.

Both curvatons can produce large, small, or negative non-Gaussianity.

The model is consistent with hierarchical neutrino masses.

Abstract

In this paper, we consider the effect of two right-handed sneutrino curvaton decays and investigate the parameter space. We compare the difference of the result between single- and two-curvaton cases. We find one Yukawa coupling of the right-handed snetrinos can be as large as $\lambda \sim 0.1$ while the other one is much smaller which is consistent with the idea that only one generation of the neutrino mass may be much smaller than others. When the curvatons decay, we assume both of them subdominate the energy density of the universe. We find that, unlike a single curvaton case, here a small or negative, as well as a large $f_{NL}$ can be generated.