Dark Matter and Baryogenesis from Non-Abelian Gauged Lepton Number

Abstract: A simple model is constructed based on the gauge symmetry $SU(3)c \times SU(2)_L \times U(1)_Y \times SU(2)\ell$, with only the leptons transforming nontrivially under $SU(2)\ell$. The extended symmetry is broken down to the Standard Model gauge group at TeV-scale energies. We show that this model provides a mechanism for baryogenesis via leptogenesis in which the lepton number asymmetry is generated by $SU(2)\ell$ instantons. The theory also contains a dark matter candidate - the $SU(2)_\ell$ partner of the right-handed neutrino.