The electron-flavored Z'-portal dark matter and the DAMPE cosmic ray excess

The DAMPE experiment has recently reported strong indications for the existence of an excess of high-energy electrons and positrons. If interpreted in terms of the annihilation of dark matter, the DAMPE result restricts the dark matter mass and possible annihilation channels to a few case. In this paper we explain the DAMPE result with the electron-flavored $Z^{\mathrm{\prime }}$-portal fermionic dark matter. We show that the Dirac dark matter scenario is promising to explain the excess via the process $\bar \chi \chi \to$\mathbf{Z}$'\to \bar e e$\mathrm{.}Thereducedannihilationcrosssectionislimitedinarangeof$10^{-26}\sim 10^{-24}~{\rm cm^3 s^{-1}}$ to interpret the excess.