Neutrino Mass and the KATRIN Experiment

Neutrinos are probably the most abundant elementary particles in the Universe. Originally introduced to save the energy conservation in nuclear beta decay, the neutrinos are becoming a power tool in particle physics, astrophysics and cosmology. Until recently, the neutrinos were treated as massless particles but the neutrino oscillation experiments proved that at least some of them are massive. The theory is yet unable to predict the neutrino mass and various experiments supplied until now only its upper limits. Recent investigation of the tritium beta spectrum shape led to the model independent neutrino mass limit of 2.3 eV/c2. The new Karlsruhe Tritium Neutrino Experiment (KATRIN), http://www-ik.fzk.de/~katrin, http://ojs.ujf.cas.cz/~rysavy/katr1.htm, should either determine the neutrino mass or set its limit to 0.2 eV/c2.