A comment on the measurement of neutrino masses in β-decay experiments

We discuss the physics potential of future tritium β-decay experiments having a sensitivity to a neutrino mass ∼|Δm232|∼5×10−2eV. The case of three-neutrino mixing is analyzed. A negative result of such an experiment would imply that the neutrino mass spectrum is of normal hierarchical type. The interpretation of a positive result would depend on the value of the lightest neutrino mass; if the lightest neutrino mass satisfies the inequality min(mj)≪|Δm232|, it would imply that the neutrino mass spectrum is of the inverted hierarchical type.