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

TL;DR

This paper proposes that electron-flavored Z'-portal fermionic dark matter can explain the DAMPE cosmic ray excess, with specific annihilation channels and cross sections fitting the observed data.

Contribution

It introduces a Dirac dark matter model with Z'-portal interactions that can account for the DAMPE excess through electron-positron annihilation.

Findings

The model explains the DAMPE excess with a dark matter mass constrained by observations.

The annihilation cross section range compatible with the excess is identified.

The Dirac dark matter scenario provides a promising explanation for the 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 $\bar \chi \chi \to\mathbf{Z}'\to \bar e e$. The reduced annihilation cross section is limited in a range of $10^{-26}\sim 10^{-24}~{\rm cm^3 s^{-1}}$ to interpret the excess.