论文标题
MajoriaMaana示范者搜索$^{76} $ ge的双β衰减到$^{76} $ se的激发状态
The Majorana Demonstrator's Search for Double-Beta Decay of $^{76}$Ge to Excited States of $^{76}$Se
论文作者
论文摘要
Majoraana示范器是一个中微子双β衰减搜索，该搜索由低背景模块化阵列组成，高纯晶式探测器，$ \ sim2/3 $，其中的$ \ sim2/3 $在$^{76} $ ge中富集至88 \％。该实验还在搜索$^{76} $ ge的双β衰减到$^{76} $ se中的激发态（E.S.）。 $^{76} $ ge可以腐烂到$^{76} $ se的三个女儿状态，并带有由$ββ$ -DECAY组成的明确事件签名，然后迅速排放一两个$γ$ -rays。这导致多探测器的巧合可能性很高。演示器检测器阵列的粒度可以从背景中对此事件签名进行强大的歧视。使用41.9〜 kg-y的同位素暴露，演示者为每个E.S. \ $^{76} $ ge设定了世界领先的限制，其中90 \％Cl下半寿命限制范围为$（0.75-4.0）\ times10^{24} $ 〜y。特别是，对于$2ν$过渡到第一个$ 0^+$ e.s.
The Majorana Demonstrator is a neutrinoless double-beta decay search consisting of a low-background modular array of high-purity germanium detectors, $\sim2/3$ of which are enriched to 88\% in $^{76}$Ge. The experiment is also searching for double-beta decay of $^{76}$Ge to excited states (e.s.) in $^{76}$Se. $^{76}$Ge can decay into three daughter states of $^{76}$Se, with clear event signatures consisting of a $ββ$-decay followed by the prompt emission of one or two $γ$-rays. This results with high probability in multi-detector coincidences. The granularity of the Demonstrator detector array enables powerful discrimination of this event signature from backgrounds. Using 41.9~kg-y of isotopic exposure, the Demonstrator has set world leading limits for each e.s.\ decay of $^{76}$Ge, with 90\% CL lower half-life limits in the range of $(0.75-4.0)\times10^{24}$~y. In particular, for the $2ν$ transition to the first $0^+$ e.s.\ of $^{76}$Se, a lower half-life limit of $7.5\times10^{23}$~y at 90\% CL was achieved.
