Results of the Mainz neutrino mass experiment

The Mains neutrino mass experiment investigates the endpoint region of the tritium beta decay spectrum to determine the mass of the electron antineutr ino. By the recent upgrade the former problem of dewetting T-2 films has be en solved and the signal-to-background-ratio was improved by a factor of 10 . The latest measurement leads to m(nu)(2) = -1.1 +/- 2.6(stat) +/- 1.8(sys ) eV(2)/c(4) (preliminary), which corresponds to an upper limit of m(nu) < 2.3 eV/c(2) (95 % C.L.) (preliminary). Some indication for the anomaly, rep orted by the Troitsk group, was found, but its postulated half year period is contradicted by our data.