Gauged Flavour for Asymmetric Dark Matter

TL;DR

This paper introduces a framework linking Standard Model flavour hierarchies to asymmetric dark matter generation via leptogenesis, involving a gauged SO(3) symmetry and a confining SU(3) for dark matter.

Contribution

It proposes a novel model connecting flavour symmetry breaking, leptogenesis, and dark matter, with detailed phenomenological and cosmological constraints analysis.

Findings

Dark matter as baryon-like bound states of a confining SU(3)

Flavour, collider, and cosmological constraints shape the model's parameter space

Potential collider signatures from mirror fermions and flavour violating decays

Abstract

We propose a framework that links the origin of the Standard Model flavour hierarchies to the generation of asymmetric dark matter via leptogenesis. The key new ingredient is a gauged $SO(3)$ flavour symmetry acting on both the visible and dark sectors, whose spontaneous breaking generates fermion mass hierarchies. Right-handed neutrino decays produce a primordial lepton asymmetry, which is redistributed into baryon and dark matter asymmetries by electroweak and flavour sphalerons respectively. Dark matter arises as baryon-like bound states of a confining $SU(3)$, providing a natural rationale for the similar mass scales of visible and dark matter. We analyze flavour, collider, electroweak, and cosmological constraints. Anomaly cancellation requires the presence of mirror fermions, inducing a seesaw-like suppression of new physics effects in the lighter generations, such that different observables are sensitive to different flavour-breaking scales. Meson oscillations provide the dominant constraints, with $K$ and $B_s$ observables constraining the highest and intermediate scales, while the lowest scale may place some mirror fermions potentially within reach of future collider searches and is currently probed by flavour violating $B_s$ decays and electroweak observables. Flavour interactions are also bounded from below by the requirement of a sufficiently fast decay of the symmetric dark matter component, leading to a tightly constrained and predictive scenario testable through several complementary probes.