Particle and gravitational wave probes of minimal seesaw neutrinos

A bstract Observable gravitational waves (GWs) from first-order phase transitions (FOPTs) can coexist with distinct particle physics signatures. These include same-sign dilepton plus four jet events at colliders, such as e + e − / μ + μ − → ℓ ± ℓ ± 4 j , neutrinoless double beta decay, as well as charged lepton flavor violating (cLFV) processes such as μ → eγ . We explore this synergy within the minimal low-scale linear seesaw model. This framework successfully reproduces neutrino oscillation data, providing a direct avenue to probe the neutrino mass ordering and Majorana nature at colliders. Crucially, the FOPT responsible for the GW background is driven by a leptophilic Higgs doublet, establishing a direct link between early-universe cosmology and terrestrial laboratory experiments.