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Latest Results from the Heidelberg-Moscow Double Beta Decay Experiment

H. V. Klapdor-Kleingrothaus·A. Dietz·L. Baudis·G. Heusser·I. V. Krivosheina·S. Kolb·B. Majorovits·H. Paes·H. Strecker·V. Alexeev·A. Balysh·A. Bakalyarov·S. T. Belyaev·V. I. Lebedev·S. Zhukov
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Abstract

New results for the double beta decay of 76Ge are presented. They are extracted from Data obtained with the HEIDELBERG-MOSCOW, which operates five enriched 76Ge detectors in an extreme low-level environment in the GRAN SASSO. The two neutrino accompanied double beta decay is evaluated for the first time for all five detectors with a statistical significance of 47.7 kg y resulting in a half life of (T_(1/2))^(2nu) = [1.55 +- 0.01 (stat) (+0.19) (-0.15) (syst)] x 10^(21) years. The lower limit on the half-life of the 0nu beta-beta decay obtained with pulse shape analysis is (T_(1/2))^(0_nu) > 1.9 x 10^(25) [3.1 x 10^(25)] years with 90% C.L. (68% C.L.) (with 35.5 kg y). This results in an upper limit of the effective Majorana neutrino mass of 0.35 eV (0.27 eV). No evidence for a Majoron emitting decay mode or for the neutrinoless mode is observed.

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H. V. Klapdor-Kleingrothaus, A. Dietz, L. Baudis, G. Heusser, I. V. Krivosheina, S. Kolb, B. Majorovits, H. Paes, H. Strecker, V. Alexeev, A. Balysh, A. Bakalyarov, S. T. Belyaev, V. I. Lebedev, S. Zhukov. 2001-03-06. Latest Results from the Heidelberg-Moscow Double Beta Decay Experiment. https://doi.org/10.1007/s100500170022

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