Search for neutrinoless τ decays involving the KS0 meson

Abstract

We have searched for lepton flavor violating decays of the τ lepton with at least one K S 0 meson in the final state. The data used in the search were collected with the CLEO II and ILV detectors at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 13.9 fb −1 at the Ψ(45) resonance. No evidence for signals were found, therefore we have set 90% confidence level (C.L.) upper limits on the branching fractions B (τ − → e − K S 0) < 9.5 × 10 −7, B (τ − → μ − K S 0) < 9.5 × 10 −7, B (τ − → e − K S 0 K S 0) < 2.4 × 10 −6, and B (τ − → μ − K S 0 K S 0 < 3.5 × 10 −6. These represent significantly improved upper limits on the two-body decays and first upper limits on the three-body decays.