AbstractResults are reported from a search for the lepton flavor violating decayτ →3μin proton-proton collisions at$$ \sqrt{\mathrm{s}} $$s= 13 TeV. The data sample corresponds to an integrated luminosity of 33.2 fb−1recorded by the CMS experiment at the LHC in 2016. The search exploitsτleptons produced in both W boson and heavy-flavor hadron decays. No significant excess above the expected background is observed. An upper limit on the branching fraction ℬ(τ →3μ) of 8.0×10−8at 90% confidence level is obtained, with an expected upper limit of 6.9×10−8.
