Leptophilic dark matter in gauged $U(1)_{L_e-L_\mu}$ model in light of DAMPE cosmic ray $e^+ + e^-$ excess

TL;DR

This paper explores a gauged $U(1)_{L_e-L_}$ model with Dirac fermion dark matter to explain the DAMPE cosmic-ray excess, analyzing its detection prospects and implications for muon g-2.

Contribution

It introduces a leptophilic dark matter model that accounts for DAMPE data and examines its experimental constraints and phenomenological implications.

Findings

The model can fit DAMPE data well.

Most of the $Z'$ mass range is excluded by direct detection limits.

Allowed $Z'$ mass is near twice the dark matter mass.

Abstract

Motivated by the very recent cosmic-ray electron+positron excess observed by DAMPE collaboration, we investigate a Dirac fermion dark matter (DM) in the gauged $L_e - L_\mu$ model. DM interacts with the electron and muon via the $U(1)_{e-\mu}$ gauge boson $Z^{'}$. The model can explain the DAMPE data well. Although a non-zero DM-nucleon cross section is only generated at one loop level and there is a partial cancellation between $Z^{'}ee$ and $Z^{'}\mu\mu$ couplings, we find that a large portion of $Z^{'}$ mass is ruled out from direct DM detection limit leaving the allowed $Z^{'}$ mass to be close to two times of the DM mass. Implications for $pp \to Z^{'} \to 2\ell$ and $pp \to 2\ell + Z^{'}$ , and muon $g-2$ anomaly are also studied.