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arXiv · 1110.3923

Final results of an experiment to search for 2beta processes in zinc and tungsten with the help of radiopure ZnWO4 crystal scintillators

P. Belli·R. Bernabei·F. Cappella·R. Cerulli·F. A. Danevich·S. d'Angelo·A. Incicchitti·V. V. Kobychev·D. V. Poda·V. I. Tretyak
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Abstract

A search for the double beta decay of zinc and tungsten isotopes has been performed with the help of radiopure ZnWO4 crystal scintillators (0.1-0.7 kg) at the Gran Sasso National Laboratories of the INFN. The total exposure of the low background measurements is 0.529 kg yr. New improved half-life limits on the double beta decay modes of 64Zn, 70Zn, 180W, and 186W have been established at the level of 10^{18}-10^{21} yr. In particular, limits on double electron capture and electron capture with positron emission in 64Zn have been set: T_{1/2}(2ν2K) > 1.1 10^{19} yr, T_{1/2} (0ν2ε) > 3.2 10^{20} yr, T_{1/2} (2νεβ^+) > 9.4 10^{20} yr, and T_{1/2} (0νεβ^+) > 8.5 10^{20} yr, all at 90% C.L. Resonant neutrinoless double electron capture in 180W has been restricted on the level of T_{1/2} (0ν2ε) > 1.3 10^{18} yr. A new half-life limit on alpha transition of 183W to the metastable excited level 1/2^- 375 keV of 179Hf has been established: T_{1/2} > 6.7 10^{20} yr.

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P. Belli, R. Bernabei, F. Cappella, R. Cerulli, F. A. Danevich, S. d'Angelo, A. Incicchitti, V. V. Kobychev, D. V. Poda, V. I. Tretyak. 2011-10-18. Final results of an experiment to search for 2beta processes in zinc and tungsten with the help of radiopure ZnWO4 crystal scintillators. https://doi.org/10.1088/0954-3899%2F38%2F11%2F115107

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