From NANOGrav to LIGO with metastable cosmic strings

TL;DR

This paper links recent NANOGrav gravitational wave observations to metastable cosmic strings, suggesting detectable signals for ground-based interferometers and connecting the findings to grand unification theories, inflation, leptogenesis, and dark matter.

Contribution

It provides a novel interpretation of NANOGrav results as arising from metastable cosmic strings and explores their implications for fundamental physics.

Findings

The stochastic gravitational wave background can be explained by metastable cosmic strings.

Predicted signals are within reach of current ground-based interferometers.

The results connect gravitational wave observations to grand unification and early universe phenomena.

Abstract

We interpret the recent NANOGrav results in terms of a stochastic gravitational wave background from metastable cosmic strings. The observed amplitude of a stochastic signal can be translated into a range for the cosmic string tension and the mass of magnetic monopoles arising in theories of grand unification. In a sizable part of the parameter space, this interpretation predicts a large stochastic gravitational wave signal in the frequency band of ground-based interferometers, which can be probed in the very near future. We confront these results with predictions from successful inflation, leptogenesis and dark matter from the spontaneous breaking of a gauged B-L symmetry.