Gravitational Wave Probes of Massive Gauge Bosons at the Cosmological Collider

TL;DR

This paper explores how massive gauge bosons produced during inflation can generate detectable gravitational wave signals across a wide range of scales, extending the cosmological collider's reach from CMB to interferometers.

Contribution

It introduces a model with Chern-Simons coupling that enhances gauge boson production and derives constraints and predictions for gravitational wave signals detectable by current and future interferometers.

Findings

Massive gauge fields during inflation produce characteristic gravitational wave signals.

The model's signals can be detected across the entire range of current and planned interferometers.

Updated constraints on parameter space from CMB observations.

Abstract

We extend the reach of the ``cosmological collider'' for massive gauge boson production during inflation from the CMB scales to the interferometer scales. Considering a Chern-Simons coupling between the gauge bosons and the pseudoscalar inflaton, one of the transverse gauge modes is efficiently produced and its inverse decay leaves an imprint in the primordial scalar and tensor perturbations. We study the correlation functions of these perturbations and derive the updated constraints on the parameter space from CMB observables. We then extrapolate the tensor power spectrum to smaller scales consistently taking into account the impact of the gauge field on inflationary dynamics. Our results show that the presence of massive gauge fields during inflation can be detected from characteristic gravitational wave signals encompassing the whole range of current and planned interferometers.