NANOGrav results and Dark First Order Phase Transitions

TL;DR

The paper interprets NANOGrav's gravitational wave signals as originating from first order phase transitions in the early universe, particularly within warm dark matter models like Majoron Dark Matter, at keV-MeV temperatures.

Contribution

It proposes a novel interpretation of NANOGrav data linking it to low-temperature first order phase transitions in dark matter models, expanding the potential sources of primordial gravitational waves.

Findings

GW spectrum consistent with FOPTs at keV-MeV temperatures

FOPTs in warm dark matter models can produce detectable GW signals

Supports the connection between dark matter physics and gravitational wave observations

Abstract

The recent NANOGrav evidence of a common-source stochastic background provides a hint to Gravitational Waves (GW) radiation from the Early Universe. We show that this result can be interpreted as a GW spectrum produced from First Order Phase Transitions (FOPTs) around a temperature in the KeV-MeV window. Such a class of FOPTs at temperatures much below the electroweak scale can be naturally envisaged in several Warm Dark Matter models such as Majoron Dark Matter.