Limit on the tau neutrino mass

A limit on the tau neutrino mass M_ντ is obtained from a study of tau decays in the reaction e⁺{e}^{{{-}}}→{{{τ}}}⁺τ^- at center-of-mass energies {~}10.6 GeV. The result is based on an end-point analysis of the invariant mass spectrum of the decay products in the decay modes τ^-{→}3h^-2h⁺{{ν}}_{{{τ}}}$ and ${{{τ}}}^{{{-}}}→2{h}^{{{-}}}h⁺2π⁰{{ν}}_{{{τ}}}. The data sample used in this analysis contains 1.77×{10}⁶$ tau pairs, corresponding to an integrated luminosity of 1.92 ${fb}^{{{-}}1}$, and is substantially larger than previous data samples used to place a limit on ${M}_{{ν}{{τ}}}$. The limit obtained for both five-hadron modes together is 32.6 MeV at 95% C.L.