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

Abstract

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 $${{L_e} - {L_\mu }}$$ Le-Lμ model. DM interacts with the electron and muon via the $$U(1)_{e-\mu }$$ U(1)e-μ gauge boson $$Z^\prime $$ 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 $$Z^{\prime }ee$$ Z′ee and $$Z^{\prime }\mu \mu $$ Z′μμ couplings, we find that a large portion of $$Z\prime $$ Z′ mass is ruled out from direct DM detection limit leaving the allowed $$Z^{\prime }$$ Z′ mass to be close to two times of the DM mass. Implications for $$pp \rightarrow Z^{\prime } \rightarrow 2\ell $$ pp→Z′→2ℓ and $$pp \rightarrow 2\ell + Z^{\prime }$$ pp→2ℓ+Z′ , and muon $$g-2$$ g-2 anomaly are also studied.