We provide a simple UV theory for Dirac dark matter with a massless Abelian gauge boson. We introduce a single fermion transforming as the 16 representation in the SO(10)′ gauge group, which is assumed to be spontaneously broken to SU(5)′×U(1)′. The SU(5)′ gauge interaction becomes strong at an intermediate scale, and then we obtain a light composite Dirac fermion with U(1)′ gauge interaction at a low-energy scale. Its thermal relic can explain the observed amount of dark matter consistently with other cosmological and astrophysical constraints. The dark matter mass and U(1)′ fine-structure constant are predicted to be 600-700 GeV and (2.5-2.9)×10-2, respectively. We discuss that a nonzero kinetic mixing between the U(1)′ gauge boson and the hypercharge gauge boson is allowed and the temperature of the visible sector and the dark matter sector can be equal to each other.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)