Cosmological Collider Physics and the Curvaton

TL;DR

This paper explores how the curvaton scenario in cosmology can produce significantly larger non-Gaussian signals from heavy particles than standard inflation, potentially observable in future experiments.

Contribution

It demonstrates that the curvaton framework allows for enhanced non-Gaussian signatures from heavy particles, expanding the scope of cosmological collider physics beyond standard inflation.

Findings

Heavy particle couplings can produce large non-Gaussian signals.

Signals from heavy gauge-charged scalars and fermions are within observational reach.

The model maintains effective field theory control of inflationary dynamics.

Abstract

Primordial non-Gaussianity signatures of extremely heavy particles are re-examined within a simple alternative to the standard inflationary paradigm, in which the primordial fluctuations and the inflationary spacetime expansion are sourced by two different fields. The curvaton scenario provides an example of this in which the distinct roles are played by the curvaton and the inflaton fields, respectively. We study couplings of the curvaton to heavy particles with masses of order the inflationary Hubble scale, and show that they can lead to non-Gaussian signals orders of magnitude larger than those in standard inflation, consistent with explicit effective field theory control of inflationary dynamics. This brings various motivated particle physics signatures, such as loops of heavy gauge-charged scalars and fermions, within future observational reach.