Dark Matter, Neutrino mass, Cutoff for Cosmic-Ray Neutrino, and Higgs Boson Invisible Decay from a Neutrino Portal Interaction

Understand

We study an effective theory beyond the standard model (SM) where either of two additional gauge singlets, a Majorana fermion and a real scalar, constitutes all or some fraction of dark matter.

• In particular, we focus on the masses of the two singlets in the range of O(10) MeV-O(10) GeV, with a neutrino portal interaction which plays important roles not only in particle physics but also in cosmology and astronomy.
• We point out that the dark matter abundance can be thermally explained with (co)annihilation, where the dark matter with a mass greater than 2 GeV can be tested in future lepton colliders, CEPC, ILC, FCC-ee and CLIC, in the light of the Higgs boson invisible decay.
• When the gauge singlets are lighter than O(100)MeV, the interaction can affect the neutrino propagation in the universe due to its annihilation with the cosmic background neutrino into the gauge singlets.