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arXiv · 1703.01877

The first result on 76Ge neutrinoless double beta decay from CDEX-1 experiment

Abstract

We report the first result on Ge-76 neutrinoless double beta decay from CDEX-1 experiment at China Jinping Underground Laboratory. A mass of 994 g p-type point-contact high purity germanium detector has been installed to search the neutrinoless double beta decay events, as well as to directly detect dark matter particles. An exposure of 304 kg*day has been analyzed. The wideband spectrum from 500 keV to 3 MeV was obtained and the average event rate at the 2.039 MeV energy range is about 0.012 count per keV per kg per day. The half-life of Ge-76 neutrinoless double beta decay has been derived based on this result as: T 1/2 > 6.4*10^22 yr (90% C.L.). An upper limit on the effective Majorana-neutrino mass of 5.0 eV has been achieved. The possible methods to further decrease the background level have been discussed and will be pursued in the next stage of CDEX experiment.

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Li Wang, Qian Yue, KeJun Kang, JianPing Cheng, YuanJing Li, TszKing Henry Wong, ShinTed Lin, JianPing Chang, JingHan Chen, QingHao Chen, YunHua Chen, Zhi Deng, Qiang Du, Hui Gong, Li He, QingJu He, JinWei Hu, HanXiong Huang, TengRui Huang, LiPing Jia, Hao Jiang, HauBin Li, Hong Li, JianMin Li, Jin Li, Jun Li, Xia Li, XinYing Li, XueQian Li, YuLan Li, FongKay Lin, ShuKui Liu, Hao Ma, JingLu Ma, XingYu Pan, Jie Ren, XiChao Ruan, ManBin Shen, Vivek Sharma, Lakhwinder Singh, Manoj Kumar Singh, Arun Kumar Soma, Jian Su, ChangJian Tang, WeiYou Tang, ChaoHsiung Tseng, JiMin Wang, Qing Wang, ShiYong Wu, Wei Wu, YuCheng Wu, HaoYang Xing, Yin Xu, Tao Xue, LiTao Yang, SongWei Yang, Nan Yi, ChunXu Yu, HaiJun Yu, WeiHe Zeng, XiongHui Zeng, Zhi Zeng, Lan Zhang, YunHua Zhang, MingGang Zhao, Wei Zhao, SuNing Zhong, JiFang Zhou, ZuYing Zhou, JingJun Zhu, WeiBin Zhu, ZhongHua Zhu. 2017-03-06. The first result on 76Ge neutrinoless double beta decay from CDEX-1 experiment. https://doi.org/10.1007/s11433-017-9038-4

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