Neutrino rest mass and anomaly in the tritium β spectrum

The results of the 'Troitsk ν-mass' experiment on the search for the neutrino rest mass in the tritium β-decay are presented. The study of the time dependence of an anomalous, bump-like structure at the end of β-spectrum reported earlier, gives an indication of a periodic shift of the position of the bump with respect to the end-point energy with a period of 0.5 year. A new upper limit for the electron antineutrino rest mass m2ν<2.5 eV/c2 is derived after taking into account the effect of the bump