Lepton Flavor Violation of Z Gauge Boson Decays in Supersymmetric Type-III Seesaw Model

Abstract: In this study, we investigate the lepton flavor violation (LFV) of Z gauge boson decaying into two different flavor charged leptons $Z\longrightarrow l_i l_j$ ($Z\longrightarrow \tau \mu$, $Z\longrightarrow \tau e$ and $Z\longrightarrow \mu e$). This work is performed in the framework of the constrained minimal supersymmetric standard model (CMSSM) which is extended by the type-III seesaw mechanism. By considering constraints from the current experimental bounds on neutrino and supersymmetric particle masses, we calculate the branching ratios of the LFV of Z boson decays. The numerical results are found to be $1.30 \times {10}^{-9}$ for both the $\tau \mu$ and $\tau e$ decay channels and $6.40 \times {10}^{-10}$ for the $\mu e$ channel. After applying the constraints from the experimental bounds on the radiative two body decays $l_{i}\rightarrow l_{j} \gamma$, the branching ratios of the LFV of Z boson decays get an additional suppression of $10^{-3}$ for the $\tau \mu$ and $\tau e$ decay channels and $10^{-8}$ for the $\mu e$ channel. The prediction of the branching ratios is found to be several orders of magnitude below the current experimental bounds for both scenarios. Thus the LFV of Z boson decays could be observed with low likelihood in the future collider experiments.