Upper limit on the vτ mass from τ → 3hv τ decays
G Alexander, J Allison, N Altekamp, K Ametewee, KJ Anderson, S Anderson, S Arcelli, S Asai, D Axen, G Azuelos, AH Ball, E Barberio, RJ Barlow, R Bartoldus, JR Batley, G Beaudoin, J Bechtluft, C Beeston, T Bebnke, AN Bell Show all
Zeitschrift fur Physik C-Particles and Fields | Published : 1996
A new technique has been used to determine a limit on the vτ mass using Z0 → τ+τ- events selected from 140 pb-1 of data collected with the OPAL detector at LEP during the period 1990-1994. Using Z0 → τ +τ- events in which both τ-leptons decay to three charged particles, a novel likelihood analysis is applied to the 2-dimensional distribution of missing mass squared and missing energy, from which we obtain a limit of Mvτ. < 35.3 MeV at 95% confidence level. Combining our new result with OPAL's previous published measurement from τ → 5πvτ, decays, we obtain the new 95% confidence level limit of Mvτ, < 29.9 MeV. © Springer-Verlag 1996.