Precise determination of the mass difference 76Ge76Se and a derived upper limit on the Majorana mass of the electron neutrino

Abstract Recent improvements to both the instrumentation and data analysis techniques associated with the Manitoba II high resolution mass spectrometer have led to greater precision and accuracy. The mass difference between 76 Ge and 76 Se has been redetermined to be 2038.58 (31) keV. When the new 76 Ge double-beta decay Q -value is used to examine recent spectra reported by groups searching for the characteristic sharp peak expected for neutrinoless double-beta decay, no evidence for the occurrence of such a decay is found. New upper limits can be derived for the electron neutrino mass. Reanalysis of earlier data is also presented, leading to a value for the mass difference 74 Se 74 Ge of 1209.53 (48) keV.