Search for 2β decays of 96Ru and 104Ru by ultra-low background HPGe gamma spectrometry at LNGS: final results
P. Belli, R. Bernabei, F. Cappella, R. Cerulli, F. A. Danevich, S. d'Angelo, A. Incicchitti, G. P. Kovtun, N. G. Kovtun, M. Laubenstein, D. V. Poda, O. G. Polis… 展开作者
P. Belli, R. Bernabei, F. Cappella, R. Cerulli, F. A. Danevich, S. d'Angelo, A. Incicchitti, G. P. Kovtun, N. G. Kovtun, M. Laubenstein, D. V. Poda, O. G. Polischuk, A. P. Shcherban, D. A. Solopikhin, J. Suhonen, V. I. Tretyak
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14 pages, 5 figures, 2 tables; version accepted for publication on Phys. Rev. C
An experiment to search for double beta decay processes in 96Ru and 104Ru, which are accompanied by gamma rays, has been realized in the underground Gran Sasso National Laboratories of the I.N.F.N. (Italy). Ruthenium samples with masses of about (0.5-0.7) kg were measured with the help of ultra-low background high purity Ge gamma ray spectrometry. After 2162 h of data taking the samples were deeply purified to reduce the internal contamination of 40K. The last part of the data has been accumulated over 5479 h. New improved half life limits on 2β+/εβ+/2ε processes in 96Ru have been established on the level of 10^{20} yr, in particular for decays to the ground state of 96Mo: T1/2(2ν2β+) > 1.4 10^{20} yr, T1/2(2νεβ+) > 8.0 10^{19} yr and T1/2(0ν2K) > 1.0 10^{21} yr (all limits are at 90% C.L.). The resonant neutrinoless double electron captures to the 2700.2 keV and 2712.7 keV excited states of 96Mo are restricted as: T1/2(0νKL) > 2.0 10^{20} yr and T1/2(0ν2L) > 3.6 10^{20} yr, respectively. Various two neutrino and neutrinoless 2β half lives of 96Ru have been estimated in the framework of the QRPA approach. In addition, the T1/2 limit for 0ν2β- transitions of 104Ru to the first excited state of 104Pd has been set as > 6.5 10^{20} yr.
Double-beta decay of $^{150}$Nd to excited levels of $^{150}$Sm
INFN sezione Roma “Tor Vergata”（罗马大学托维尔加塔分校INFN分部）；Institute for Nuclear Research of NASU（乌克兰国家科学院核研究所）；National University of Life and Environmental Sciences of Ukraine（乌克兰国立大学生命与环境科学大学）；INFN sezione Roma（罗马INFN分部）；Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所）；University of Chinese Academy of Sciences（中国科学院大学）；INFN Laboratori Nazionali del Gran Sasso（INFN大萨索国家实验室）；Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava（布拉迪斯拉发康斯坦丁尼茨大学数学、物理和信息学院）；International Centre for Advanced Training and Research in Physics（国际高级物理培训与研究中心）；“Horia Hulubei” National Institute of Physics and Nuclear Engineering（“霍里亚·胡卢贝伊”核物理与核工程国家研究所）；State Scientific Institution “Institute for Single Crystals” of NASU（乌克兰国家科学院单晶研究所）；Institute of Experimental and Applied Physics, Czech Technical University in Prague（捷克布拉格理工大学实验与应用物理研究所）；Institute for Scintillation Materials of NASU（乌克兰国家科学院闪烁材料研究所）
