Search for lepton-flavor-violating τ decays into three leptons with 719 million produced τ+τ− pairs

摘要

We present a search for lepton-flavor-violating tau decays into three leptons(electrons or muons) using 782 fb^-1 of data collected with the Belle detectorat the KEKB asymmetric-energy e+e- collider. No evidence for these decays isobserved and we set 90% confidence level upper limits on the branchingfractions between 1.5 x 10^-8 and 2.7 x 10^-8.