Search for neutrinoless β+ EC decay of Te120 with CUORE
Search for neutrinoless β+ EC decay of Te120 with CUORE
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使用 CUORE 搜索 Te120 的无中微子 β EC 衰变
DOI：
10.1103/physrevc.105.065504
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发表时间：
2022
影响因子：
3.1
通讯作者：
Biassoni, M.
中科院分区：
文献类型：
--
作者：
Adams, D. Q.;Alduino, C.;Alfonso, K.;Avignone, F. T.;Azzolini, O.;Bari, G.;Bellini, F.;Benato, G.;Beretta, M.;Biassoni, M.
稀有事件低温地下观测站（英语：Cryogenic Underground Observatory for Rare Events，简称CUORE）是一个大型低温实验，目的是寻找130 Te中的无中微子双β衰变（0νββ）。CUORE探测器由天然碲制成，提供了对130 Te以外的同位素进行稀有事件搜索的可能性。在这项工作中，我们描述了在120 Te的无中微子正电子发射的电子捕获（β+ EC）衰变的研究，总TeO 2曝光量为355.7千克/年，相当于0.2405千克/年的120 Te。尽管具有两个终态电子的0νββ代表了最有希望的通道，但一个正电子和两个511 keV γ的发射使得0νβ+ EC衰变特征非常清楚。为了充分利用探测器模块化提供的潜力，我们包括具有不同拓扑结构的事件，并同时拟合五个选定的信号特征。使用盲法数据，我们提取了在90%可信区间（C.I.）时的中位排除敏感性为3.4 × 1022年。在揭盲后，我们没有发现0νβ+ EC信号的证据，并设定90% C. I. 120 Te半衰期的贝叶斯下限为2.9 × 1022年。这一结果提高了一个数量级的现有限制从CUORE-0和Cuoricino的组合分析。
The Cryogenic Underground Observatory for Rare Events (CUORE) is a large-scale cryogenic experiment searching for neutrinoless double-beta decay (0νββ) in 130Te. The CUORE detector is made of natural tellurium, providing the possibility of rare event searches on isotopes other than 130Te. In this work we describe a search for neutrinoless positron-emitting electron capture (β+ EC ) decay in 120Te with a total TeO2 exposure of 355.7 kg yr, corresponding to 0.2405 kg yr of 120Te. Albeit 0νββ with two final-state electrons represents the most promising channel, the emission of a positron and two 511-keV γ 's make 0νβ+ EC decay signature extremely clear. To fully exploit the potential offered by the detector modularity we include events with different topology and perform a simultaneous fit of five selected signal signatures. Using blinded data we extract a median exclusion sensitivity of 3.4 × 1022 yr at 90% credibility interval (C.I.). After unblinding we find no evidence of 0νβ+ EC signal and set a 90% C.I. Bayesian lower limit of 2.9 × 1022 yr on 120Te half-life. This result improves by an order of magnitude the existing limit from the combined analysis of CUORE-0 and Cuoricino.