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An upper limit for the tau-neutrino mass from tau --> 5 pi+- nutau decays

The OPAL Collaboration, K. Ackerstaff et al

hep-exarXiv:hep-ex/9806035

Abstract

An upper limit for the tau-neutrino mass has been determined from the decay tau -> 5pi+- νtau 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 5pi invariant mass and energy distribution from 22 selected events. Combining this result with OPAL's previously published measurement using tau+tau- -> 3h+- nutau 3h-+ νtau decays, a new combined limit of mnutau < 27.6 MeV (95% CL) is obtained.

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