# Unification for the Darkly Charged Dark Matter

## TL;DR

This paper proposes a UV-complete model for dark matter involving a composite Dirac fermion with a massless gauge boson, unifying dark matter and gauge interactions within a grand unified framework.

## Contribution

It introduces a novel SO(10)' based UV theory that naturally produces a light composite Dirac dark matter particle with a massless gauge boson, consistent with cosmological constraints.

## Key findings

- The model yields the correct relic abundance of dark matter.
- It allows for kinetic mixing between dark and visible sector gauge bosons.
- The theory remains consistent with astrophysical and cosmological observations.

## Abstract

We provide a simple UV theory for a Dirac dark matter with a massless Abelian gauge boson. We introduce a single fermion transforming as the $\bf{16}$ representation in the SO(10)$'$ gauge group, which is assumed to be spontaneously broken to SU(5)$'\times$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 the low-energy scale. Its thermal relic can explain the observed amount of dark matter consistently with other cosmological and astrophysical constraints. 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.