Search for Neutrinoless Double-Beta Decay with the Upgraded EXO-200 Detector
Search for Neutrinoless Double-Beta Decay with the Upgraded EXO-200 Detector
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DOI：
10.1103/physrevlett.120.072701
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发表时间：
2018-02-15
影响因子：
8.6
通讯作者：
Ziegler, T.
中科院分区：
文献类型：
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作者：
Albert, J. B.;Anton, G.;Ziegler, T.
对Xe-136的无中微子双β衰变(0nuβ)的搜索结果是用升级后的EXO-200探测器第一年的数据给出的。与EXO-200以前的搜索相比，探测器的能量分辨率提高到sigma/E=1.23%，漂移区的电场提高了50%，并实现了低温恒温器与铅屏蔽之间体积的氡抑制系统。此外，还开发了改进0nuβ和背景事件之间的拓扑区分的分析技术。结合这些硬件和分析改进，在结合升级前获得的完整数据集后，中位数90%置信度级别0 nu beta半衰期灵敏度增加了两倍，达到3.7x10(25)年。没有观察到有统计学意义的0nuββ证据，导致在90%的置信度水平下，0nuββ半衰期的下限为1.8x10(25)年。
Results from a search for neutrinoless double-beta decay (0 nu beta beta) of Xe-136 are presented using the first year of data taken with the upgraded EXO-200 detector. Relative to previous searches by EXO-200, the energy resolution of the detector has been improved to sigma/E = 1.23%, the electric field in the drift region has been raised by 50%, and a system to suppress radon in the volume between the cryostat and lead shielding has been implemented. In addition, analysis techniques that improve topological discrimination between 0 nu beta beta and background events have been developed. Incorporating these hardware and analysis improvements, the median 90% confidence level 0 nu beta beta half-life sensitivity after combining with the full data set acquired before the upgrade has increased twofold to 3.7 x 10(25) yr. No statistically significant evidence for 0 nu beta beta is observed, leading to a lower limit on the 0 nu beta beta half-life of 1.8 x 10(25) yr at the 90% confidence level.