We report a measurement of the branching ratios for two decay modes of the τ lepton: RB(τ±→K±Kπ±ντ)=(0.22-0. 11+0.17)% and RB(τ±→K±ππ±(π0)ντ)= (0.22-0.13+0.16)%. The separation of these channels is accomplished in the DELCO detector by use of a gas erenkov counter to identify fast kaons. The invariant-mass distribution of the K±Kπ± system has been used to set an upper bound on the τ neutrino mass of 157 MeV at 95% confidence limit.
ASJC Scopus subject areas
- Physics and Astronomy(all)