SLAC National Accelerator Laboratory, Stanford, California, USA.
Phys Rev Lett. 2011 Nov 18;107(21):212501. doi: 10.1103/PhysRevLett.107.212501. Epub 2011 Nov 17.
We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.
我们报告了在 (136)Xe 中观察到的双β衰变，半衰期为 T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) 年。这个由标准模型预测的二级过程已经在几种核中被观察到，但在 (136)Xe 中没有观察到。观测到的衰变率为矩阵元计算和寻找更有趣的无中微子双β衰变提供了新的输入，无中微子双β衰变是探测马约拉纳粒子存在和测量中微子质量尺度的最敏感探针。
