利用 GERDA 第二阶段的无本底无中微子双贝塔衰变搜寻
核实验
2017-04-07 v2 高能物理 - 实验
仪器与探测器
摘要
粒子物理标准模型无法解释我们宇宙中物质相对于反物质的优势地位。在许多模型扩展中,中微子是其自身的反粒子(马约拉纳粒子)是一个很自然的结论,这意味着一种违反轻子数的放射性衰变,即无中微子双贝塔 () 衰变应当存在。探测这一极其稀有的假想过程需要最大程度地抑制各类本底。GERDA 合作组通过运行由富集 Ge 分数的锗制成的裸探测器置于液氩中,来搜寻 Ge 的 衰变()。在此,我们报告 GERDA 第二阶段的首批数据。已实现 cts/(keVkgyr) 的本底水平,若按锗探测器的窄能量信号区加权,此为世界最佳。结合第一阶段与第二阶段数据,我们未发现信号,并推导出在 90% 置信度 (C.L.) 下半衰期的新下限 yr。我们的灵敏度 yr 与同位素质量显著更大的实验相当。GERDA 是首个在其设计曝光量内将实现无本底的 实验。这一进展依赖于新颖的主动否决系统、优越的锗探测器能量分辨率以及我们新探测器改进的本底识别能力。本质上无本底搜寻 衰变的独特发现潜力推动了具有更高灵敏度的更大规模锗实验。
引用
@article{arxiv.1703.00570,
title = {Background free search for neutrinoless double beta decay with GERDA Phase II},
author = {M. Agostini and M. Allardt and A. M. Bakalyarov and M. Balata and I. Barabanov and L. Baudis and C. Bauer and E. Bellotti and S. Belogurov and S. T. Belyaev and G. Benato and A. Bettini and L. Bezrukov and T. Bode and D. Borowicz and V. Brudanin and R. Brugnera and A. Caldwell and C. Cattadori and A. Chernogorov and V. D'Andrea and E. V. Demidova and N. DiMarco and A. diVacri and A. Domula and E. Doroshkevich and V. Egorov and R. Falkenstein and O. Fedorova and K. Freund and N. Frodyma and A. Gangapshev and A. Garfagnini and C. Gooch and P. Grabmayr and V. Gurentsov and K. Gusev and J. Hakenmüller and A. Hegai and M. Heisel and S. Hemmer and W. Hofmann and M. Hult and L. V. Inzhechik and J. Janicskó Csáthy and J. Jochum and M. Junker and V. Kazalov and T. Kihm and I. V. Kirpichnikov and A. Kirsch and A. Kish and A. Klimenko and R. Kneißl and K. T. Knöpfle and O. Kochetov and V. N. Kornoukhov and V. V. Kuzminov and M. Laubenstein and A. Lazzaro and V. I. Lebedev and B. Lehnert and H. Y. Liao and M. Lindner and I. Lippi and A. Lubashevskiy and B. Lubsandorzhiev and G. Lutter and C. Macolino and B. Majorovits and W. Maneschg and E. Medinaceli and M. Miloradovic and R. Mingazheva and M. Misiaszek and P. Moseev and I. Nemchenok and D. Palioselitis and K. Panas and L. Pandola and K. Pelczar and A. Pullia and S. Riboldi and N. Rumyantseva and C. Sada and F. Salamida and M. Salathe and C. Schmitt and B. Schneider and S. Schönert and J. Schreiner and O. Schulz and A. -K. Schütz and B. Schwingenheuer and O. Selivanenko and E. Shevchik and M. Shirchenko and H. Simgen and A. Smolnikov and L. Stanco and L. Vanhoefer and A. A. Vasenko and A. Veresnikova and K. von Sturm and V. Wagner and M. Walter and A. Wegmann and T. Wester and C. Wiesinger and M. Wojcik and E. Yanovich and I. Zhitnikov and S. V. Zhukov and D. Zinatulina and K. Zuber and G. Zuzel},
journal= {arXiv preprint arXiv:1703.00570},
year = {2017}
}
备注
14 pages, 9 figures, 1 table; ; data, figures and images available at http://www.mpi-hd.mpg/gerda/public