Dark matter and muon (g − 2) in local U(1)Lμ−LτU(1)Lμ−Lτ-extended Ma model

We consider right-handed neutrino dark matter N1N1 in local U(1)Lμ−LτU(1)Lμ−Lτ-extended Ma model. With the light U(1)μ−τU(1)μ−τ gauge boson (mZ′∼O(100) MeVmZ′∼O(100) MeV) and small U(1)μ−τU(1)μ−τ gauge coupling (gZ′∼10−4–10−3gZ′∼10−4–10−3) which can accommodate the muon (g−2)(g−2) anomaly and is still allowed by other experimental constraints, we show that we can get correct relic density of dark matter for wide range of dark matter mass (M1∼10–200 GeVM1∼10–200 GeV), although the gauge coupling constant gZ′gZ′ is small. This is due to the fact that the annihilation cross section of dark matter pair is enhanced by M14/mZ′4 in the processes N1N1→Z′Z′N1N1→Z′Z′ or N1N1→Z′H2N1N1→Z′H2. We also consider the constraints from direct detection, collider searches.