Limit on the tau neutrino mass from τ→π-π+π-π 0ντ

From a data sample of 29058 {tau}{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup +}{pi}{sup -}{pi}{sup 0}{nu}{sub {tau}} decays observed in the CLEO detector we derive a 95% confidence upper limit on the tau neutrino mass of 28 MeV. (c) 2000 The American Physical Society.