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

Abstract

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 $Z^{\prime }$-portal fermionic dark matter. We show that the Dirac dark matter scenario is promising to explain the excess via the process $\bar{\chi }\chi \to {\mathbf{Z}}^{\prime }\to \bar{e}e$. The reduced annihilation cross section is limited in a range of $10^{-26}\sim 10^{-24}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}$ to interpret the excess.

Comments: 17 pages, 4 figures