Dark Matter Stability from residual flavour symmetries

We propose a model-independent framework in which Dark Matter stability emerges naturally from residual discrete Z N symmetries left unbroken by the spontaneous breaking of continuous flavour symmetries, both Abelian and non-Abelian. No ad hoc stabilizing symmetry is required, as Dark Matter stability is an inherent consequence of the underlying flavour dynamics. As an explicit example, we construct a prototype model based on a SU(2) F U(1) F Froggatt-Nielsen symmetry, which successfully reproduces the observed charged lepton mass spectrum and the PMNS mixing matrix, while identifying the lightest sterile neutrino as a stable Dark Matter candidate. Furthermore, we study the Dark Matter phenomenology within our model in the freeze-in regime, including production channels mediated by higher-dimensional operators suppressed by the cutoff scale Λ. Our analysis shows that continuous flavour symmetries can provide a unified, self-consistent framework addressing both the flavour puzzle and the origin, stability, and production of Dark Matter.