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

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 $Z^{{}^{\prime }}$. 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 $Z^{{}^{\prime }}ee$ and $Z^{{}^{\prime }}\mu \mu$ couplings, we find that a large portion of $Z^{{}^{\prime }}$ mass is ruled out from direct DM detection limit leaving the allowed $Z^{{}^{\prime }}$ mass to be close to two times of the DM mass. Implications for $pp\to Z^{{}^{\prime }}\to 2\ell$ and $pp\to 2\ell +Z^{{}^{\prime }}$ , and muon $g-2$ anomaly are also studied.

Comments: Discussions added, version accepted by EPJC