Dark gauge bosons: LHC signatures of non-abelian kinetic mixing

Abstract

We consider non-abelian kinetic mixing between the Standard Model SU(2)[subscript L] and a dark sector U(1)′ gauge group associated with the presence of a scalar SU(2)[subscript L] triplet. The magnitude of the resulting dark photon coupling ϵ is determined by the ratio of the triplet vacuum expectation value, constrained to by ≲4 GeV by electroweak precision tests, to the scale Λ of the effective theory. The corresponding effective operator Wilson coefficient can be O(1) while accommodating null results for dark photon searches, allowing for a distinctive LHC dark photon phenomenology. After outlining the possible LHC signatures, we illustrate by recasting current ATLAS dark photon results into the non-abelian mixing context.