Quasi-degenerate dark photon and dark matter

We introduce an $SU(2{)}_X^{}$ dark sector without any fermions and then realize a non-abelian kinetic mixing between the dark $SU(2{)}_X^{}$ gauge fields and the standard model $SU(2{)}_L^{}\times U(1{)}_Y^{}$ gauge fields. While one of the dark gauge bosons becomes a dark photon, the others can keep stable to form a dark matter particle. The nearly degenerate masses of dark photon and dark matter could be tested if the dark photon and the dark matter are both observed in the future.