Asymmetric Dark Matter and Baryogenesis from $SU(2{)}_{\ell }$

Abstract

We propose a theory in which the Standard Model gauge symmetry is extended by a new $SU(2{)}_{\ell }$ group acting nontrivially on the lepton sector which is spontaneously broken at the TeV scale. Under this $SU(2{)}_{\ell }$ the ordinary leptons form doublets along with new lepton partner fields. This construction naturally contains a dark matter candidate, the partner of the right-handed neutrino, stabilized by a residual global $U(1{)}_{\chi }$ symmetry. We show that one can explain baryogenesis through an asymmetric dark matter scenario, in which generation of related asymmetries in the dark matter and baryon sectors is driven by the $SU(2{)}_{\ell }$ instantons during a first order phase transition in the early universe.

Comments: Version accepted for publication in Physical Review D. 11 pages, 4 figures. References added, minor changes