A precise measurement of the tau lifetime

2004 European Physical Journal C: Particles and Fields  
The tau lepton lifetime has been measured with the e + e − → τ + τ − events collected by the DELPHI detector at LEP in the years 1991-1995. Three different methods have been exploited, using both one-prong and three-prong τ decay channels. Two measurements have been made using events in which both taus decay to a single charged particle. Combining these measurements gave τ τ (1 prong) = 291.8 ± 2.3 stat ± 1.5 sys fs. A third measurement using taus which decayed to three charged particles
more » ... ed particles yielded τ τ (3 prong) = 288.6 ± 2.4 stat ± 1.3 sys fs. These were combined with previous DELPHI results to measure the tau lifetime, using the full LEP1 data sample, to be τ τ = 290.9 ± 1.4 stat ± 1.0 sys fs.
doi:10.1140/epjc/s2004-01953-7 fatcat:iyniwic2hzdetnqrv6j2ym6tle