Dark symmetry implication for right-handed neutrinos

We argue that the long-standing issues of neutrino mass and dark matter can be manifestly solved in a dark gauge symmetry U(1)D that transforms nontrivially only for three right-handed neutrinos ν1,2,3R -- the counterparts of known left-handed neutrinos. This theory assigns ν1,2,3R dark charge to be $D=0$, $-1$, and $+1$, respectively, in order for anomaly cancelation. Additionally, it imposes an inert Higgs doublet η and two Higgs singlets ξ,φ with dark charge $D=+1$, $-1$, and $+2$, respectively. That said, the dark symmetry is broken by φ (by two units) down to a dark parity PD=(-1)D, for which ν2,3R and η,ξ are odd, whereas all other fields are even due to $D=0$. The lightest of these odd fields is stabilized by PD, responsible for dark matter. Neutrino masses are generated by a scotoseesaw scheme, in which the seesaw part is mediated by ν1R, while the scotogenic part is mediated by ν2,3R, for which the hierarchy of atmospheric and solar neutrino mass splittings is explained.