2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/207414An upper limit for the tau-neutrino mass has been determined from the decay tau -> 5pi+- ν_tau using data collected with the OPAL detector from 1991 to 1995 in e+e- collisions at \sqrt{s} ~ M_Z. 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+- \bar{nu}_tau 3h-+ ν_tau decays, a new combined limit of m_{nu_tau} < 27.6 MeV (95% CL) is obtained.17 pages, LaTeX, 4 eps figures included, submitted to Eur. Phys. JHigh Energy Physics - Experimenttext