Upper limit on the electron antineutrino mass from the Troitsk experiment

Abstract

An electron antineutrino mass has been measured in tritium $\ensuremath{\beta}$ decay in the Troitsk $\ensuremath{\nu}$-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 ${m}_{\ensuremath{\nu}}^{2}=\ensuremath{-}0.67\ifmmode\pm\else\textpm\fi{}2.53\text{ }\text{ }{\mathrm{eV}}^{2}$. This gives an experimental upper sensitivity limit of ${m}_{\ensuremath{\nu}}<2.2\text{ }\text{ }\mathrm{eV}$, 95% C.L. and upper limit estimates ${m}_{\ensuremath{\nu}}<2.12\text{ }\text{ }\mathrm{eV}$, 95% C.L. for Bayesian statistics and ${m}_{\ensuremath{\nu}}<2.05\text{ }\text{ }\mathrm{eV}$, 95% C.L. for the Feldman and Cousins approach.