# New Shapes of Primordial Non-Gaussianity from Quasi-Single Field Inflation with Multiple Isocurvatons

## TL;DR

This paper explores how multiple isocurvatons during inflation can produce distinctive non-Gaussian features in primordial fluctuations, with potential observational signatures in large-scale structure.

## Contribution

It introduces a model with multiple isocurvatons affecting non-Gaussianities, revealing new shape features in the bispectrum due to kinetic mixings.

## Key findings

- Squeezed bispectrum amplitude can grow as (k_s/k_l)^{-3}
- Oscillatory behavior in non-Gaussian shape with log dependence
- Potential observational signatures in large-scale structure

## Abstract

We study a simple extension of quasi-single field inflation in which the inflaton interacts with multiple extra massive scalars known as isocurvatons. Due to the breaking of time translational invariance by the inflaton background, the theory includes kinetic mixings among the inflaton and isocurvatons. These mixings give rise to novel new features in the primordial non-Gaussianities of the scalar curvature perturbation. A noteworthy feature is the amplitude of the squeezed bispectrum can grow nearly as $(k_s/k_l)^{-3}$ while oscillating as ${\rm \cos\gamma \log}(k_s/k_l)$, where $k_s/k_l$ is the ratio of the lengths of the short and long wavevectors. Observation of such a shape would provide evidence for the existence of multiple isocurvatons during inflation. In addition, we consider the effects of these non-Gaussianities on large-scale structure.