Weak Decay of Tellurium and Barium Isotopes in Geological Samples: Current Status

The accurate experimental determination of half-lives for 2 nu beta beta-decay could be used to adjust parameters of the QRPA model, the strength of the particle-particle interaction g(pP) and to improve the calculation of Nuclear Matrix Element for 0 nu beta beta (neutrinoless) decay and neutrino mass < m(nu)> estimations. Presently high precision direct counting experiments are difficult due to low decay rates of tellurium and barium isotopes, but their daughter nuclei accumulating in geological samples for millions of years, are clearly observable in xenon isotopes, which have extremely low background in terrestrial rocks. This work reviews current status of the previously determined half-lives of Te-130 and Te-128 and presents new estimates of half-life of Ba-130 weak decay. Our new estimates take into account the spallogenic production of Xe-130, significantly reducing the disagreement between the only two published values of Ba-130 half-lives. Based on this result and on our early experiments we propose a new class of geological samples, which can provide an even more accurate determination of the Ba-130 half-life.