Bound on the mass of Majorana neutrinos after SNO and KamLAND

Abstract

Presently the best terrestrial limit on light neutrino masses (m<2.2 eV) are given by the tritium beta decay experiments. Not maximal mixing of solar neutrinos following from the SNO and KamLAND together with neutrinoless double beta decay (( )0 ) data open the chance for better determination of the lightest of Majorana neutrino mass. We combine all available fits for the solar neutrino parameters and collect all Nuclear Matrix Elements (NME) calculations for the 76Ge, nucleus for which presently the most stringent limit on the ( )0 decay half-life time exist. We have shown that for some NME smaller bound on (m )min can be found. Unfortunately one order of magnitude discrepancies in NME calculations do not allow to give the final answer.