Light vector dark matter with scalar mediator and muon g-2 anomaly.

We study a model with a vector dark matter candidate interacting with the SM charged leptons through a scalar portal. The dark matter candidate acquires mass when the scalar breaks an abelian gauge symmetry spontaneously. The scalar mediator being leptophilic only induces elastic scattering of dark matter with electrons at the leading order (tree level). Given the recent results from Xenon1T upper bounds on dark matter-electron elastic scattering cross section where the strongest sensitivity lies in the range $\sim {\cal O}$(1) GeV, we find the viable space in the parameter space respecting constraints from the observed relic density, muon g-2 anomaly, $e^+ e^-$ colliders, electron beam-dump experiments and astrophysical observables. It is shown that the current upper bounds of Xenon1T is partially sensitive to the viable parameter space, such that it excludes the scalar mediator with masses $m_s \lesssim 3$ MeV for DM masses $m_{\text{DM}} \sim 0.1-10$ GeV. We also found that the sensitivity reach of the Xenon1T is about one order of magnitude weaker than that of the electron beam-dump experiments.