Upper Limit On The Electron Antineutrino Mass From The Troitsk Experiment

An electron antineutrino mass has been measured in tritium beta decay in the Troitsk nu-mass experiment. The setup consists of a windowless gaseous tritium source and an electrostatic electron spectrometer. The whole data set acquired from 1994 to 2004 was reanalyzed. A thorough selection of data with the reliable experimental conditions has been performed. We checked every known systematic effect and obtained the following experimental estimate for neutrino mass squared m(nu)(2) = -0.67 +/- 2.53 eV(2). This gives an experimental upper sensitivity limit of m(nu) < 2.2 eV, 95% C. L. and upper limit estimates m(nu) < 2.12 eV, 95% C. L. for Bayesian statistics and m(nu) < 2.05 eV, 95% C. L. for the Feldman and Cousins approach.