A Comparative Study of Z${}^{\mathrm{\prime }}$ mediated Charged Lepton Flavor Violation at future lepton colliders

Charged lepton flavor violation (CLFV) represents a transition between charged leptons of different generations that violates lepton flavor conservation, which is a clear signature of possible new physics beyond the standard model. By exploiting a typical example model of extra Z${}^{\mathrm{\prime }}$ gauge boson, we perform a detailed comparative study on CLFV searches at several future lepton colliders, including a 240 GeV electron-positron collider and a TeV scale muon collider. Based on detailed signal and background Monte-Carlo studies with fast detector simulations, we derive the potentials in searching for Z${}^{\mathrm{\prime }}$ mediated CLFV couplings with $e\mu$, $e\tau$ and $\mu \tau$ of different future colliders. The results are compared with the current limits set by either low-energy experiments or the high-energy LHC experiments. We find that the sensitivity of the $\tau$ related CLFV coupling strength at future lepton colliders will be significantly improved comparing with the current best constraints.