Direct determination of the neutrino masses

The only model-independent method to determine the absolute neutrino mass scale is still the investigation of a β decay spectrum near its endpoint. The tritium β decay experiments at Mainz and Troitsk have recently been finished yielding upper limits on the neutrino mass of about 2 eV. The bolometric experiments using 187Re reached a sensitivity on the neutrino mass of 15 eV. The new Karlsruhe Tritium Neutrino Experiment (KATRIN) will enhance the sensitivity on the neutrino mass by another order of magnitude down to 0.2 eV by using a very strong windowless gaseous molecular tritium source and a huge ultra-high resolution electrostatic spectrometer of MAC-E-Filter type to probe the cosmological relevant neutrino mass range and scenarios of quasi-degenerated neutrino masses. To cite this article: C. Weinheimer, C. R. Physique 6 (2005).