Neutrino mass limits from a precise determination of -decay rates of Te128 and Te130

Double beta decay of Te128 has been confirmed and the ratio of half-lives for decay of Te130 and Te128 has been determiend as Te1/2130/128Te1/2=(3.520.11) ×10-4 by ion-counting mass spectrometry of Xe in ancient Te ores. The Xe measurements, combined with common Pb dating, yield a Te130 half-life of (2.70.1)×1021 yr and thus a Te128 half-life of (7.70.4)×1024 yr. These results give limits on the effective Majorana mass of the neutrino (<1.1-1.5 eV) and right-handed currents (>5.3×10-8) comparable to the best obtained from direct neutrinoless -decay searches. They also imply new limits on nonstandard Majorons not constrained by measurements of the Z0 decay width.