Prospects for Cosmological Collider Physics

TL;DR

This paper explores the potential of future 21-cm cosmological surveys to detect signatures of heavy fields during inflation through non-Gaussianities, offering a new window into the particle spectrum of the early universe.

Contribution

It develops model-independent templates for bispectrum analysis and forecasts detection thresholds for various particle masses and interactions using 21-cm data during the dark ages.

Findings

Future 21-cm surveys could detect signatures of heavy fields during inflation.

Templates effectively distinguish inflationary signals from secondary non-Gaussianities.

Detection of new particles with different masses and interactions is possible with upcoming experiments.

Abstract

It is generally expected that heavy fields are present during inflation, which can leave their imprint in late-time cosmological observables. The main signature of these fields is a small amount of distinctly shaped non-Gaussianity, which if detected, would provide a wealth of information about the particle spectrum of the inflationary Universe. Here we investigate to what extent these signatures can be detected or constrained using futuristic 21-cm surveys. We construct model-independent templates that extract the squeezed-limit behavior of the bispectrum, and examine their overlap with standard inflationary shapes and secondary non-Gaussianities. We then use these templates to forecast detection thresholds for different masses and couplings using a 3D reconstruction of modes during the dark ages ($z\sim 30-100$). We consider interactions of several broad classes of models and quantify their detectability as a function of the baseline of a dark ages interferometer. Our analysis shows that there exists the tantalizing possibility of discovering new particles with different masses and interactions with future 21-cm surveys.