Abstract
A radiopure cadmium tungstate crystal scintillator, enriched in 106 Cd to 66%, with mass of 216 g (106CdWO4) was used in coincidence with four ultra-low background HPGe detectors contained in a single cryostat to search for double beta (2β) decay processes in 106 Cd. New improved half-life limits on the 2β processes in 106 Cd have been set on the level of 1020 — 1021 yr after 13085 h of data taking deep underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN (Italy). In particular, the limit on the two neutrino electron capture with positron emission, Tεβ+21/2≥ 1.1 × 1021 yr, has reached the region of theoretical predictions. The resonant neutrinoless double electron captures to the 2718, 2741 and 2748 keV excited states of 106 Pd are restricted on the level of T2ε0v1/2 ≥ (8.5 × 1020 - 1.4 × 1021) yr.
Highlights
While we already know from experiments on neutrino oscillations that ν’s have non-zero masses, their absolute values are unknown because these investigations are sensitive only to differences in ν mass squares [1]
We did not find any peculiarities in the data accumulated with the 106CdWO4 and HPGe detectors that could be ascribed to the 2β processes in 106Cd
Give only the half-life limits according to a formula: lim T1/2 = ln 2 · N · η · t/ lim S, where N is the number of 106Cd nuclei in the 106CdWO4 crystal (N = 2.42 × 1023), η is the detection efficiency, t is the time of measurements, and lim S is the number of events of the effect searched for, which can be excluded at a given confidence level (C.L.)
Summary
While we already know from experiments on neutrino oscillations that ν’s have non-zero masses, their absolute values are unknown because these investigations are sensitive only to differences in ν mass squares [1]. Fit of the 106CdWO4 anticoincidence spectrum by the background model, and its main components are shown in Fig. 1 (right).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
