论文标题
搜索中微子$β^+ec $ $^{120} $ te与cuore
Search for Neutrinoless $β^+EC$ Decay of $^{120}$Te with CUORE
论文作者
论文摘要
Cuore是一个大规模的低温实验,在$^{130} $ TE中寻找中微子双β衰减($0νββ$)。 Cuore探测器由天然三学生制成,提供了在$^{130} $ TE以外的同位素上进行罕见事件搜索的可能性。在这项工作中,我们描述了在$^{{120} $ TE中搜索中微子positron发射电子捕获($0νβ^+ec $)的衰减,总计teo $ _2 $暴露于355.7 kg $ \ cdot $ yr,对应于0.2405 kg $ \ cdot $ yr $ yr $^yr $^{120} $ yr。尽管具有两个最终状态电子的$ 0νββ$代表了最有前途的渠道,但正电子的发射和两个511-kev $γ$ s的发射使$0νβ^+ec $ $ n衰变签名非常清楚。为了完全利用检测器模块化提供的电势,我们包括具有不同拓扑的事件,并同时拟合了五个选定的信号特征。使用盲数据,我们提取$ 3.4 \ cdot 10^{22} $ yr的中值排除灵敏度在90%的信誉间隔(C.I。)。未闪烁后,我们找不到$0νβ^+ec $信号的证据,并将90%C.I设定。贝叶斯的下限$ 2.9 \ cdot 10^{22} $ yr $^{120} $ te半寿命。该结果通过数量级提高了Cuore-0和Cuoricino的组合分析的现有限制。
CUORE is a large scale cryogenic experiment searching for neutrinoless double beta decay ($0νββ$) in $^{130}$Te. The CUORE detector is made of natural tellurium, providing the possibility of rare event searches on isotopes other than $^{130}$Te. In this work we describe a search for neutrinoless positron emitting electron capture ($0νβ^+EC$) decay in $^{120}$Te with a total TeO$_2$ exposure of 355.7 kg $\cdot$ yr, corresponding to 0.2405 kg $\cdot$ yr of $^{120}$Te. Albeit $0 νββ$ 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 $3.4 \cdot 10^{22}$ 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 $2.9 \cdot 10^{22}$ yr on $^{120}$Te half-life. This result improves by an order of magnitude the existing limit from the combined analysis of CUORE-0 and Cuoricino.