Neutrinoless double-beta decay and double-electron capture

Studies on double beta decay processes in 106Cd were performed by using a cadmium tungstate scintillator enriched in 106Cd at 66% (106CdWO4) with two CdWO4 scintillation counters (with natural Cd composition). No effect was observed in the data that accumulated over 26,033 h. New improved half-life limits were set on the different channels and modes of the 106Cd double beta decay at level of limT1/2∼1020−1022 yr. The limit for the two neutrino electron capture with positron emission in 106Cd to the ground state of 106Pd, T1/22νECβ+≥2.1×1021 yr, was set by the analysis of the 106CdWO4 data in coincidence with the energy release 511 keV in both CdWO4 counters. The sensitivity approaches the theoretical predictions for the decay half-life that are in the range T1/2∼1021−1022 yr. The resonant neutrinoless double-electron capture to the 2718 keV excited state of 106Pd is restricted at the level of T1/20ν2K≥2.9×1021 yr.

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Study of rare nuclear processes with CUORE

International Journal of Modern Physics A ◽

10.1142/s0217751x18430029 ◽

2018 ◽

Vol 33 (09) ◽

pp. 1843002 ◽

Cited By ~ 6

Author(s):

C. Alduino ◽

K. Alfonso ◽

F. T. Avignone ◽

O. Azzolini ◽

G. Bari ◽

...

Keyword(s):

Dark Matter ◽

Electron Capture ◽

Beta Decay ◽

Upper Bound ◽

Half Life ◽

Particle Physics ◽

Neutrinoless Double Beta Decay ◽

Double Beta Decay ◽

Small Scale ◽

Nuclear Processes

TeO2 bolometers have been used for many years to search for neutrinoless double beta decay in [Formula: see text]Te. CUORE, a tonne-scale TeO2 detector array, recently published the most sensitive limit on the half-life, [Formula: see text] yr, which corresponds to an upper bound of 140–400 meV on the effective Majorana mass of the neutrino. While it makes CUORE a world-leading experiment looking for neutrinoless double beta decay, it is not the only study that CUORE will contribute to in the field of nuclear and particle physics. As already done over the years with many small-scale experiments, CUORE will investigate both rare decays (such as the two-neutrino double beta decay of [Formula: see text]Te and the hypothesized electron capture in [Formula: see text]Te), and rare processes (e.g. dark matter and axion interactions). This paper describes some of the achievements of past experiments that used TeO2 bolometers, and perspectives for CUORE.

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Search for neutrinoless double beta decay of $$^{64}$$Zn and $$^{70}$$Zn with CUPID-0

The European Physical Journal C ◽

10.1140/epjc/s10052-020-8280-4 ◽

2020 ◽

Vol 80 (8) ◽

Author(s):

O. Azzolini ◽

J. W. Beeman ◽

F. Bellini ◽

M. Beretta ◽

M. Biassoni ◽

...

Keyword(s):

Electron Capture ◽

Beta Decay ◽

Credible Interval ◽

Neutrinoless Double Beta Decay ◽

Double Beta Decay ◽

Experimental Results ◽

Next Generation ◽

Pilot Experiment ◽

Order Of Magnitude ◽

G 38

Abstract CUPID-0 is the first pilot experiment of CUPID, a next-generation project searching for neutrinoless double beta decay. In its first scientific run, CUPID-0 operated 26 ZnSe cryogenic calorimeters coupled to light detectors in the underground Laboratori Nazionali del Gran Sasso. In this work, we analyzed a ZnSe exposure of 11.34 kg year to search for the neutrinoless double beta decay of $$^{70}$$70Zn and for the neutrinoless positron-emitting electron capture of $$^{64}$$64Zn. We found no evidence for these decays and set 90$$\%$$% credible interval limits of $$\hbox {T}_{1/2}^{0\nu \beta \beta }$$T1/20νββ($$^{70}$$70Zn) > 1.6 $$10^{21}$$1021 year and $$\hbox {T}_{1/2}^{0\nu EC \beta +}$$T1/20νECβ+($$^{64}$$64Zn) > 1.2$$\times 10^{22}$$×1022 year, surpassing by more than one order of magnitude the previous experimental results (Belli et al. in J Phys G 38(11):115107, https://doi.org/10.1088/0954-3899/38/11/115107, 2011).

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Sensitivity of the NEXT experiment to Xe-124 double electron capture

Journal of High Energy Physics ◽

10.1007/jhep02(2021)203 ◽

2021 ◽

Vol 2021 (2) ◽

Author(s):

G. Martínez-Lema ◽

◽

M. Martínez-Vara ◽

M. Sorel ◽

C. Adams ◽

...

Keyword(s):

Electron Capture ◽

Simulated Data ◽

Real Data ◽

Double Beta Decay ◽

Current Sensitivity ◽

Event Selection ◽

Double Electron Capture ◽

Nuclear Process ◽

The Standard Model ◽

Double Electron

Abstract Double electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture (2νEC EC) has been predicted for a number of isotopes, but only observed in 78Kr, 130Ba and, recently, 124Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, 0νEC EC. Here we report on the current sensitivity of the NEXT-White detector to 124Xe 2νEC EC and on the extrapolation to NEXT-100. Using simulated data for the 2νEC EC signal and real data from NEXT-White operated with 124Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of 124Xe and for a 5-year run, a sensitivity to the 2νEC EC half-life of 6 × 1022 y (at 90% confidence level) or better can be reached.

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