Direct measurements of neutrino mass

The most compelling evidence of the existence for neutrino masses are the up-down asymmetry of the atmospheric muon neutrino flux and, more recently, the measurement of the solar electron neutrino flux. These experiments, which are interpreted on the basis of the flavor oscillation hypothesis, indicate the there is some spectrum of 3 or more masses. A combination of the experimental flavor oscillation data allows a range of splitting value among the mass eigenstates that makes very attractive the investigation in the sub eV neutrino mass range, down to 0.1 eV/c(2). The direct measurements via the beta-decay, which are the more straightforward way for determining individual mass eigenstates, must reach such a neutrino mass sensitivity, In these frame a calorimetric experiment with 187-Re, could play a starring role. In fact, a 1eV energy resolution experiment could be possible with a large array of small microcalorimeters. 0 Together with the project of 1eV resolution beta electrostatic spectrometer for tritium beta decay (KATRIN) it could be possible to fix the absolute scale of neutrino mass.