Double beta decay of ¹²⁸Te

The half-life of 128Te relative to the half-life of 130Te has been found to be t12128t12130=(1.59±0.05)×103 by measurement of the ββ-decay products, 128Xe and 130Xe, in a geologically old (2.4×109 yr) telluride ore. These results yield an upper limit on the lepton nonconservation parameter, η≤0.8×10-4. RADIOACTIVITY ββ-decay 128Te; measured T1/2=1.5×1024 yr; deduced η≤0.8×10-4. Detected excess 128Xe in old Te ore