Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA.
INFN - Sezione di Milano, Milano I-20133, Italy.
Phys Rev Lett. 2018 Mar 30;120(13):132501. doi: 10.1103/PhysRevLett.120.132501.
The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-number-violating process: ^{130}Te neutrinoless double-beta decay. Examining a total TeO_{2} exposure of 86.3 kg yr, characterized by an effective energy resolution of (7.7±0.5) keV FWHM and a background in the region of interest of (0.014±0.002) counts/(keV kg yr), we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of T_{1/2}^{0ν}(^{130}Te)>1.3×10^{25} yr (90% C.L.); the median statistical sensitivity of this search is 7.0×10^{24} yr. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find T_{1/2}^{0ν}(^{130}Te)>1.5×10^{25} yr (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find m_{ββ}<(110-520) meV, where the range reflects the nuclear matrix element estimates employed.
CUORE 实验是一个吨级的低温量热计阵列，最近在意大利的格兰萨索国家实验室开始运行。该阵列代表了该技术的重大进展，在这项工作中，我们首次将其应用于高灵敏度的寻找违反轻子数过程：^{130}Te 中微子无双重β衰变。通过分析总 TeO_{2}的暴露量为 86.3kg·yr，其有效能量分辨率为 (7.7±0.5)keV 半高全宽，感兴趣区域的背景为 (0.014±0.002)counts/(keV·kg·yr)，我们没有发现中微子无双重β衰变的证据。包括系统不确定性在内，我们对^{130}Te 的无中微子双重β衰变半衰期 T_{1/2}^{0ν}设定了下限>1.3×10^{25}yr（90%置信区间）；该搜索的中位统计灵敏度为 7.0×10^{24}yr。将此结果与两个早期实验——Cuoricino 和 CUORE-0 的结果相结合，我们发现 T_{1/2}^{0ν}(^{130}Te)>1.5×10^{25}yr（90%置信区间），这是迄今为止对该衰变的最严格限制。将此结果解释为有效马约拉纳中微子质量的限制，我们发现 m_{ββ}<(110-520)meV，其中范围反映了所采用的核矩阵元估计。
