The mass scale of neutrinos is one of the fundamental open questions in modern physics with implications in particle physics as well as in cosmology. Precision measurements of the kinematics of weak nuclear decays represent the only model independent approach to address this question in a laboratory experiment. Presently, two radioactive nuclides are in the spotlight: the evergreen 3H and the 163Ho, undergoing beta decay and electron capture respectively. Thanks to the KATRIN experiment, the present best limit on the effective electron antineutrino mass of 0.8 eV has been reached. The best limit on the effective electron neutrino mass is presently still 150 eV, obtained with the ECHo experiment with the analysis of the 163Ho spectrum. The ECHo and the HOLMES experiments, both investigating the 163Ho decay have already performed measurements which allow for improving the limit of about one order of magnitude.
In this talk, I will discuss the requirements for experiments measuring the 3H and 163Ho spectra in order to reach sub-eV sensitivity on the effective neutrino mass and present the results obtained so far. In conclusion, I will introduce planned approaches to determine the neutrino mass scale using 3H and 163Ho as well as proposals to use other nuclides with decays to excited nuclear states.
A zoom connection will be available https://us02web.zoom.us/j/83078833542?pwd=S2tJVVY3WWZHbDcvSXBhd0N4cWlCQT09