Nanohertz gravitational waves from the baryon-dark matter coincidence
Abstract
The nanohertz gravitational waves (GW) observed by pulsar timing arrays may originate from a cosmological first-order phase transition (PT) at 100 MeV. Taking this possibility seriously motivates the question: why 100 MeV? We point out that a PT at exactly those scales is predicted by the generation of the baryon asymmetry from a dark asymmetry via resonant neutron-dark matter oscillations, and we prove that this PT can induce an observable GW signal compatibly with all experimental constraints. This proposal predicts dark matter self-interactions close to their observational upper limits and lowers the maximal expected mass of neutron stars. Independently of GW, this baryogenesis mechanism is tested by searches for missing-energy at the LHC and for neutron decays. We keep the model consistent with big-bang nucleosynthesis by adding heavy neutral leptons below 100 MeV, which generate neutrino masses and can induce further experimental tests.
Keywords
Cite
@article{arxiv.2604.26860,
title = {Nanohertz gravitational waves from the baryon-dark matter coincidence},
author = {Alessia Musumeci and Jacopo Nava and Silvia Pascoli and Filippo Sala},
journal= {arXiv preprint arXiv:2604.26860},
year = {2026}
}
Comments
26 pages + appendices, 9 figures