IceCube events from heavy DM decays through the right-handed neutrino portal

The recently observed IceCube PeV events could be due to heavy dark matter (DM) decay. In this paper, we propose a simple DM model with extra U(1)XU(1)X gauge symmetry and bridge it with standard model particles through heavy right-handed neutrino. The Dirac fermion DM χ   with mass ∼5 PeV∼5 PeV can dominantly decay into a dark Higgs (ϕ), the SM Higgs (h) and a neutrino (ν). If the lifetime of χ   is ∼O(1028) s∼O(1028) s, the resulting neutrino flux can fit data consistently. The neutrino flux from χ→ϕhνχ→ϕhν in our model is softer than the one predicted from χ→νhχ→νh, for example. We also discuss a possible mechanism to produce DM with the right relic abundance.