Multipartite dark matter in SU(2)N extension of Standard Model and signatures at the LHC

Abstract

An SU(2)N extension (N stands for neutral) of the Standard Model (SM) is proposed with an additional U(1) = S′ global symmetry, which stabilizes the lightest of the vector boson (X,X̄) as dark matter (DM) through unbroken S = T3N+S′. The field content of the model is motivated to address neutrino mass generation, a possible unification to SU(7), along with spontaneous symmetry breaking of SU(2)N resulting in massive gauge bosons. None of the SM particles are charged under SU(2)N and therefore X,X̄ do not have a direct coupling to the visible sector besides a Higgs portal, which is tiny to avoid any conflict with Higgs data. We show that, a large kinematic region of this model allows the neutral component of SU(2)N scalar triplet and heavy neutrinos introduced here to become additional DM components. In this paper we explore the viability of such multipartite DM parameter space, including non-zero DM-DM interactions, to comply with relic density and direct search constraints. We also demonstrate that the model may yield hadronically quiet single lepton and two lepton signatures with missing energy at the Large Hadron Collider (LHC) that can be accessed with high luminosity.