Search of Neutrinoless Double Beta Decay with the GERDA Experiment

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• 作者：M. Agostiniⁿ ; M. Allardt^c ; A.M. Bakalyarov^l ; M. Balata^a ; I. Barabanov^j ; L. Baudis^r ; C. Bauer^f ; N. Becerici-Schmidt^m ; E. Bellotti^g ; ^h ; S. Belogurov^k ; ^j ; S.T. Belyaev^l ; G. Benato^r ; ^{gbenato@physik.uzh.ch" class="auth_mail" title="E-mail the corresponding author} ; A. Bettini^o ; ^p ; L. Bezrukov^j ; T. Bodeⁿ ; D. Borowicz^b ; V. Brudanin^d ; R. Brugnera^o ; ^p ; D. Budjá ; &scaron ; ⁿ ; A. Caldwell^m ; C. Cattadori^h ; A. Chernogorov^k ; V. D'Andrea^a ; E.V. Demidova^k ; A. Domula^c ; E. Doroshkevich^j ; V. Egorov^d ; R. Falkenstein^q ; O. Fedorova^j ; K. Freund^q ; N. Frodyma^b ; A. Gangapshev^j ; ^f ; A. Garfagnini^o ; ^p ; C. Gooch^m ; C. Gotti^g ; ^h ; P. Grabmayr^q ; V. Gurentsov^j ; K. Gusev^l ; ^d ; W. Hampel^f ; A. Hegai^q ; M. Heisel^f ; S. Hemmer^o ; ^p ; G. Heusser^f ; W. Hoffmann^f ; M. Hult^e ; L.V. Inzhechik^j ; L. Ioannucci^a ; J. Janicksó ; Csá ; thyⁿ ; J. Jochum^q ; M. Junker^a
• 关键词：neutrinoless double beta decay ; T1/20ν ; 76Ge ; enriched Ge detectors
• 刊名：Nuclear and Particle Physics Proceedings
• 出版年：2016
• 出版时间：April-June 2016
• 年：2016
• 卷：273-275
• 期：Complete
• 页码：1876-1882
• 全文大小：969 K

文摘

The GERDA (GERmanium Detector Array) is an experiment for the search of neutrinoless double beta decay (0νββ$0\nu \beta \beta$) in ⁷⁶Ge, located at Laboratori Nazionali del Gran Sasso of INFN (Italy). In the first phase of the experiment, a 90% confidence level (C.L.) sensitivity of 2.4⋅10²⁵ yr$2.4\cdot {10}^{25}\text{yr}$ on the 0νββ$0\nu \beta \beta$ decay half-life was achieved with a 21.6 kg⋅yr exposure and an unprecedented background index in the region of interest of 10⁻² counts/(keV⋅kg⋅yr). No excess of signal events was found, and an experimental lower limit on the half-life of 2.1 ⋅ 10²⁵ yr (90% C.L.) was established. Correspondingly, the limit on the effective Majorana neutrino mass is m_ee<0.2–0.4 eV$m_{ee}<0.2\text{–}0.4\text{eV}$, depending on the considered nuclear matrix element. The previous claim for evidence of a 0νββ$0\nu \beta \beta$ decay signal is strongly disfavored, and the field of research is open again.