An upper limit on additional neutrino mass eigenstate in 2 to 100 eV region from "Troitsk nu-mass" data

Understand

We performed a search for any sign of an additional neutrino mass state in beta-electron spectrum based on data reanalysis of direct electron antineutrino mass measurements in Tritium beta-decay in the Troitsk nu-mass experiment.

• The existing data set allows us to search for such a state in the mass range up to 100 eV.
• The lowest value at a 95% C.L.
• upper limit for the contribution of a heavy eigenstate into electron neutrino is around or less than 1% for masses above 20 eV.