We construct a self-interacting dark matter model that could simultaneously explain the observed muon anomalous magnetic moment. It is based on a gauged U(1)Lµ−Lτ extension of the standard model, where we introduce a vector-like pair of fermions as the dark matter candidate and a new Higgs boson to break the symmetry. The new gauge boson has a sizable contribution to muon (g − 2), while being consistent with other experimental constraints. The U(1)Lµ−Lτ Higgs boson acts as a light force carrier, mediating dark matter self-interactions with a velocity-dependent cross section. It is large enough in galaxies to thermalize the inner halo and explain the diverse rotation curves and diminishes towards galaxy clusters. Since the light mediator dominantly decays to the U(1)Lµ−Lτ gauge boson and neutrinos, the astrophysical and cosmological constraints are weak. We study the thermal evolution of the model in the early Universe and derive a lower bound on the gauge boson mass.
Bibliographical noteFunding Information:
The work of AK and KK was supported by IBS under the project code IBS-R018-D. The work of KK was supported in part by the DOE grant DE-SC0011842 at the University of Minnesota. HBY acknowledges support from U.S. Department of Energy under Grant No. DE-SC0008541 and the U.S. National Science Foundation under Grant No. NSF PHY-1748958 as part of the KITP “High Energy Physics at the Sensitivity Frontier” workshop. The work of KY was supported by JSPS KAKENHI Grant Number JP18J10202.
© The Authors.
- Beyond standard model
- Cosmology of theories beyond the SM