Light gauge boson Z′ and LFV decays of the electroweak gauge boson Z

Recently, there is a growing interest of a light leptophilic gauge boson Z′, which might explain the (g − 2)μ puzzle. Considering the constraints on the Z′ coupling Zll′, we calculate its contributions to the lepton flavor violation (LFV) decay Z → τμ. We find that this kind of new light gauge boson Z′ might make the LFV decay Z → τμ to be probed in future e+e− colliders.