Direct search for neutrino mass and anomaly in the tritium beta-spectrum

Results of the ''Troitsk ν-mass'' experiment on search for the neutrino rest mass in the tritium beta-decay are presented. Study of time dependence of anomalous, bump-like structure at the end of the beta spectrum reported earlier gives indication of a periodic shift of the position of the bump with respect to the end-point energy with period of 0.5 year. New upper limit for electron antineutrino rest mass mν < 2.5 eV/c2 is derived after accounting for the bump. (authors)