Scotogenic model from an extended electroweak symmetry

Abstract

We argue that the higher weak isospin $SU(3)_L$ manifestly unifies dark matter and normal matter in its isomultiplets for which dark matter carries a conserved dark charge while normal matter does not. The resultant gauge symmetry is given by $SU(3)_C\otimes SU(3)_L \otimes U(1)_X\otimes U(1)_G$, where the first factor is the color group, while the rest defines a theory of scotoelectroweak in which $X$ and $G$ determine electric charge $Q=T_3-1/\sqrt{3}T_8+X$ and dark charge $D=-2/\sqrt{3}T_8+G$. This setup provides both appropriate scotogenic neutrino masses and dark matter stability as preserved by a residual dark parity $P_D=(-1)^D$. Interpretation of the dark charge is further discussed, given that $SU(3)_L$ is broken at very high energy scale.