NEW RESULTS IN THE ITEP/YePI DOUBLE BETA-DECAY EXPERIMENT WITH ENRICHED GERMANIUM DETECTORS

1990 ◽  
Vol 05 (17) ◽  
pp. 1299-1306 ◽  
Author(s):  
A.A. VASENKO ◽  
I.V. KIRPICHNIKOV ◽  
V.A. KUZNETSOV ◽  
A.S. STAROSTIN ◽  
A.G. DJANYAN ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Beta Decay ◽  
Half Life ◽  
Maximum Likelihood Method ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Likelihood Method ◽  
Salt Mine ◽  
Germanium Detectors ◽  
Double Beta Decay Experiment

The search for double beta-decay of 76 Ge was carried out with a detector fabricated of enriched material (85% abundance of 76 Ge compared with 7.8% natural abundance). Measurements have been performed by the ITEP/YePI team in the Avan salt mine, 245 meters underground, situated in Yerevan, Armenia. Evidence for two-neutrino double beta-decay of 76 Ge with half-life of T1/2(2v)=(9±1) · 1020 y was obtained. New limits for neutrinoless double beta-decay, T1/2(0v)>1.3×1024 y, and double beta-decay with majoron emission T1/2(0v, B)>1×1022 y were obtained at 68% CL from mean background fluctuations. Limit for 0v-decay derived by the maximum likelihood method was T1/2>2.0×1024 y.

GERDA results and the future perspectives for the neutrinoless double beta decay search using 76Ge

2018 ◽  
Vol 33 (09) ◽  
pp. 1843004 ◽  
Author(s):  
◽  
M. Agostini ◽  
A. M. Bakalyarov ◽  
M. Balata ◽  
I. Barabanov ◽  
...  
Keyword(s):  
Phase I ◽  
Beta Decay ◽  
Phase Ii ◽  
Half Life ◽  
Liquid Argon ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Second Phase ◽  
Inverted Hierarchy ◽  
Phase Phase

The GERmanium Detector Array (GERDA) is a low background experiment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN designed to search for the rare neutrinoless double beta decay ([Formula: see text]) of [Formula: see text]Ge. In the first phase (Phase I) of the experiment, high purity germanium diodes were operated in a “bare” mode and immersed in liquid argon. The overall background level of [Formula: see text] was a factor of ten better than those of its predecessors. No signal was found and a lower limit was set on the half-life for the [Formula: see text] decay of [Formula: see text]Ge [Formula: see text] yr (90% CL), while the corresponding median sensitivity was [Formula: see text] yr (90% CL). A second phase (Phase II) started at the end of 2015 after a major upgrade. Thanks to the increased detector mass and performance of the enriched germanium diodes and due to the introduction of liquid argon instrumentation techniques, it was possible to reduce the background down to [Formula: see text]. After analyzing 23.2 kg[Formula: see text]⋅[Formula: see text]yr of these new data no signal was seen. Combining these with the data from Phase I a stronger half-life limit of the [Formula: see text]Ge [Formula: see text] decay was obtained: [Formula: see text] yr (90% CL), reaching a sensitivity of [Formula: see text] yr (90% CL). Phase II will continue for the collection of an exposure of 100 kg[Formula: see text]yr. If no signal is found by then the GERDA sensitivity will have reached [Formula: see text] yr for setting a 90% CL. limit. After the end of GERDA Phase II, the flagship experiment for the search of [Formula: see text] decay of [Formula: see text]Ge will be LEGEND. LEGEND experiment is foreseen to deploy up to 1-ton of [Formula: see text]Ge. After ten years of data taking, it will reach a sensitivity beyond 10[Formula: see text] yr, and hence fully cover the inverted hierarchy region.

scholarly journals Results from the Cuore Experiment †

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 10 ◽  
Author(s):  
Alessio Caminata ◽  
Douglas Adams ◽  
Chris Alduino ◽  
Krystal Alfonso ◽  
Frank Avignone ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Half Life ◽  
Precise Measurement ◽  
Region Of Interest ◽  
Neutrinoless Double Beta Decay ◽  
Double Beta Decay ◽  
Effective Energy ◽  
Β Decay ◽  
Compact Structure

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO 2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO 2 exposure of 86.3 kg yr , characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts / ( keV kg yr ) . In this physics run, CUORE placed a lower limit on the decay half-life of neutrinoless double beta decay of 130 Te > 1.3 · 10 25 yr (90% C.L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130 Te 2 ν β β decay with a resulting half-life of T 1 / 2 2 ν = [ 7.9 ± 0.1 ( stat . ) ± 0.2 ( syst . ) ] × 10 20 yr which is the most precise measurement of the half-life and compatible with previous results.

scholarly journals Searching for Neutrinoless Double-Beta Decay of130Te with CUORE

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
D. R. Artusa ◽  
F. T. Avignone ◽  
O. Azzolini ◽  
M. Balata ◽  
T. I. Banks ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Confidence Level ◽  
Half Life ◽  
Average Energy ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Current Status ◽  
Upper Limit

Neutrinoless double-beta (0νββ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0νββdecay of130Te using an array of 988 TeO2crystal bolometers operated at 10 mK. The detector will contain 206 kg of130Te and have an average energy resolution of 5 keV; the projected 0νββdecay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1σ(9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

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