Journal article
An upper limit for the τ-neutrino mass from τ → 5π±vτ decays
K Ackerstaff, G Alexander, J Allison, N Altekamp, KJ Anderson, S Anderson, S Arcelli, S Asai, SF Ashby, D Axen, G Azuelos, AH Ball, E Barberio, RJ Barlow, R Bartoldus, JR Batley, S Baumann, J Bechtluft, T Behnke, KW Bell Show all
European Physical Journal C | Published : 1998
Abstract
An upper limit for the τ-neutrino mass has been determined from the decay τ → 5π±vτ using data collected with the OPAL detector from 1991 to 1995 in e+e- collisions at √s ≈ Mz. A limit of 43.2 MeV at 95% CL is obtained using a two-dimensional method in the 5π invariant mass and energy distribution from 22 selected events. Combining this result with OPAL's previously published measurement using τ+ τ- → 3h±v̄τ + 3h∓vτ decays, a new combined limit of mvτ < 27.6 MeV (95% CL) is obtained.