We present the first result of the KamLAND-Zen experiment, measurement of 136-Xe double-beta decay. In an exposure of 77.6 days with 129 kg of 136-Xe, two-neutrino double-beta decay half-life is measured precisely to be T_{1/2}^{2\nu} = 2.38 +/- 0.02(stat) +/- 0.14(syst) x 10^{21} yr. This value is consistent with the measurement by EXO-200 and significantly below the lower limit obtained by previous experiment. For the neutrinoless double-beta decay half-life, improved lower limit is set to T_{1/2}^{0\nu} > 5.7 x 10^{24} yr at 90% C.L. and corresponding upper limit of the effective neutrino mass is ranged to 0.3-0.6 eV depending on the adopted nuclear matrix elements.
@article{arxiv.1205.6130,
title = {First result from KamLAND-Zen : Double beta decay with 136-Xe},
author = {A. Gando},
journal= {arXiv preprint arXiv:1205.6130},
year = {2019}
}
Comments
6 pages, 3 figures, proceedings for the Moriond 2012 EW session