A Search for Neutrinoless Double-Beta Decay in 76 Ge with 26 kg-yr of Exposure from the Majorana Demonstrator
A Search for Neutrinoless Double-Beta Decay in 76 Ge with 26 kg-yr of Exposure from the Majorana Demonstrator
复制标题
在马约拉纳演示器暴露 26 kg-yr 的 76 Ge 中寻找无中微子双贝塔衰变
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发表时间：
2019
期刊：
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通讯作者：
B. Zhu
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作者：
S. Alvis;I. Arnquist;F. Avignone;A. Barabash;C. Barton;V. Basu;F. Bertrand;B. Bos;M. Busch;M. Buuck;T. Caldwell;Yuen;C. Christofferson;P.;C. Cuesta;J. Detwiler;Y. Efremenko;H. Ejiri;S. Elliott;T. Gilliss;G. Giovanetti;M. P. Green;J. Gruszko;I. Guinn;V. Guiseppe;C. Haufe;R. Hegedus;L. Hehn;R. Henning;D. H. Aguilar;E. Hoppe;M. Howe;M. Kidd;S. Konovalov;R. Kouzes;A. M. Lopez;R. Martin;R. Massarczyk;S. Meijer;S. Mertens;J. Myslik;G. Othman;W. Pettus;A. Piliounis;A. Poon;D. Radford;J. Rager;A. Reine;K. Rielage;N. Ruof;B. Shanks;M. Shirchenko;D. Tedeschi;R. L. Varner;S. Vasilyev;B. White;J. Wilkerson;C. Wiseman;W. Xu;E. Yakushev;C.;V. Yumatov;I. Zhitnikov;B. Zhu
马约拉纳的合作正在运行一系列高纯度的Ge探测器，以寻找76Ge的无中微子双β衰变。Majorana演示器由44.1公斤的Ge探测器(在76个Ge中浓缩到88%)分成两个由超清洁材料构成的模块组成。这两个模块都包含在南达科他州铅的桑福德地下研究设施的低背景屏蔽物中。我们给出了在76Ge和26Ge中寻找无中微子双β衰变的最新结果。0±0。5公斤-年的强化暴露。由于S在Qββ的能量分辨率达到了前所未有的2.53keV半高宽，我们在感兴趣的区域观测到了一个事件，从估计的背景中预计会发生0.65个事件，导致76Ge无中微子双β衰变的下限为2。7×1025年(90%CL)，中位敏感度为4。8×1025年(90%CL)。根据所使用的矩阵元素，在200-433meV的范围内，获得了ff有效Majorana中微子质量的90%CL上限。在低本底fi曲线中测得的本底为11。9±2。0个/(半高宽t年)。
The Majorana Collaboration is operating an array of high purity Ge detectors to search for the neutrinoless double-beta decay of 76 Ge. The Majorana Demonstrator consists of 44.1 kg of Ge detectors (29.7 kg enriched to 88% in 76 Ge) split between two modules constructed from ultra-clean materials. Both modules are contained in a low-background shield at the Sanford Underground Research Facility in Lead, South Dakota. We present updated results on the search for neutrinoless double-beta decay in 76 Ge with 26 . 0 ± 0 . 5 kg-yr of enriched exposure. With the Demonstrator ’s unprecedented energy resolution of 2.53 keV FWHM at Q ββ , we observe one event in the region of interest with 0.65 events expected from the estimated background, resulting in a lower limit on the 76 Ge neutrinoless double-beta decay half-life of 2 . 7 × 10 25 yr (90% CL) with a median sensitivity of 4 . 8 × 10 25 yr (90% CL). Depending on the matrix elements used, a 90% CL upper limit on the effective Majorana neutrino mass in the range of 200-433 meV is obtained. The measured background in the low-background configurations is 11 . 9 ± 2 . 0 counts/(FWHM t yr).