We propose an extension to the Standard Model accommodating two families of Dirac neutral fermions and Majorana fermions under additional U ( 1 ) e ? μ × Z 3 × Z 2 symmetries where U ( 1 ) e ? μ is a flavor dependent gauge symmetry related to the first and second family of the lepton sector, which features a two-loop induced neutrino mass model. The two families are favored by minimally reproducing the current neutrino oscillation data and two mass difference squares and canceling the gauge anomalies at the same time. As a result, we have a prediction for neutrino masses. The lightest Dirac neutral fermion is a dark matter candidate with tree-level interaction restricted to electron, muon and neutrinos, which makes it difficult to detect in direct dark matter search as well as indirect search focusing on the τ -channel, such as through γ -rays. It may however be probed by search for dark matter signatures in electron and positron cosmic rays, and allows interpretation of a structure appearing in the CALET electron + positron spectrum around 350–400?GeV as its signature, with a boost factor ～ 40 Breit-Wigner enhancement of the annihilation cross section.
展开▼
