Results on Neutrinoless Double-βDecay ofGe76from Phase I of the GERDA Experiment

• DOI: 10.1103/physrevlett.111.122503
• Publication Date: 2013-09-20T13:42:06Z
• Authors: M. Agostini; M. Allardt; E. Andreotti; A. M. Bakalyarov; M. Balata; I. Barabanov; M. Barnabé Heider; N. Barros; L. Baudis; C. Bauer; N. Becerici-Schmidt; E. Bellotti; S. Belogurov; S. T. Belyaev; G. Benato; A. Bettini; L. Bezrukov; T. Bode; V. Brudanin; R. Brugnera; D. Budjáš; A. Caldwell; C. Cattadori; A. Chernogorov; F. Cossavella; E. V. Demidova; A. Domula; V. Egorov; R. Falkenstein; A. Ferella; K. Freund; N. Frodyma; A. Gangapshev; A. Garfagnini; C. Gotti; P. Grabmayr; V. Gurentsov; K. Gusev; K. K. Guthikonda; W. Hampel; A. Hegai; M. Heisel; S. Hemmer; G. Heusser; W. Hofmann; M. Hult; L. V. Inzhechik; L. Ioannucci; J. Janicskó Csáthy; J. Jochum; M. Junker; T. Kihm; I. V. Kirpichnikov; A. Kirsch; A. Klimenko; K. T. Knöpfle; O. Kochetov; V. N. Kornoukhov; V. V. Kuzminov; M. Laubenstein; A. Lazzaro; V. I. Lebedev; B. Lehnert; H. Y. Liao; M. Lindner; I. Lippi; X. Liu; A. Lubashevskiy; B. Lubsandorzhiev; G. Lutter; C. Macolino; A. A. Machado; B. Majorovits; W. Maneschg; M. Misiaszek; I. Nemchenok; S. Nisi; C. O’Shaughnessy; L. Pandola; K. Pelczar; G. Pessina; A. Pullia; S. Riboldi; N. Rumyantseva; C. Sada; M. Salathe; C. Schmitt; J. Schreiner; O. Schulz; B. Schwingenheuer; S. Schönert; E. Shevchik; M. Shirchenko; H. Simgen; A. Smolnikov; L. Stanco; H. Strecker; M. Tarka; C. A. Ur; A. A. Vasenko; O. Volynets; K. von Sturm; V. Wagner; M. Walter; A. Wegmann; T. Wester; M. Wojcik; E. Yanovich; P. Zavarise; I. Zhitnikov; S. V. Zhukov; D. Zinatulina; K. Zuber; G. Zuzel
• Keywords: Physics and Astronomy (all); 0103 physical sciences; 530; 01 natural sciences; double-beta decay ; germanium detectors ; gamma ray spectroscopy; GERDA - Abteilung Hofmann

Neutrinoless double beta decay is a process that violates lepton number conservation. It is predicted to occur in extensions of the standard model of particle physics. This Letter reports the results from phase I of the Germanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory (Italy) searching for neutrinoless double beta decay of the isotope (76)Ge. Data considered in the present analysis have been collected between November 2011 and May 2013 with a total exposure of 21.6 kg yr. A blind analysis is performed. The background index is about 1 × 10(-2) counts/(keV kg yr) after pulse shape discrimination. No signal is observed and a lower limit is derived for the half-life of neutrinoless double beta decay of (76)Ge, T(1/2)(0ν) >2.1 × 10(25) yr (90% C.L.). The combination with the results from the previous experiments with (76)Ge yields T(1/2)(0ν)>3.0 × 10(25) yr (90% C.L.).