Hearing the signals of dark sectors with gravitational wave detectors

TL;DR

This paper explores how gravitational wave detectors can identify signals from dark sector physics, such as phase transitions and topological defects, providing potential new avenues for discovering physics beyond the Standard Model.

Contribution

It demonstrates that gravitational wave detectors can detect signals from dark sector phase transitions and topological defects, highlighting new observational signatures for dark physics.

Findings

Dark sector phase transitions produce detectable gravitational waves at future experiments.

Topological defects like domain walls can generate signals detectable by current detectors.

Future gravitational wave observatories can probe dark sector phenomena beyond current sensitivity.

Abstract

Motivated by aLIGO's recent discovery of gravitational waves we discuss signatures of new physics that could be seen at ground and space-based interferometers. We show that a first order phase transition in a dark sector would lead to a detectable gravitational wave signal at future experiments, if the phase transition has occurred at temperatures few orders of magnitude higher than the electroweak scale. The source of gravitational waves in this case is associated with the dynamics of expanding and colliding bubbles in the early universe. At the same time we point out that topological defects, such as dark sector domain walls, may generate a detectable signal already at aLIGO. Both -- bubble and domain wall -- scenarios are sourced by semi-classical configurations of a dark new physics sector. In the first case the gravitational wave signal originates from bubble wall collisions and subsequent turbulence in hot plasma in the early universe, while the second case corresponds to domain walls passing through the interferometer at present and is not related to gravitational waves. We find that aLIGO at its current sensitivity can detect smoking-gun signatures from domain wall interactions, while future proposed experiments including the fifth phase of aLIGO at design sensitivity can probe dark sector phase transitions.