Abstract
The CUORE experiment is a large bolometric array searching for the lepton number violating neutrino-less double beta decay (
$$0\nu \beta \beta $$
0
ν
β
β
) in the isotope
$$\mathrm ...{^{130}Te}$$
130
Te
. In this work we present the latest results on two searches for the double beta decay (DBD) of
$$\mathrm {^{130}Te}$$
130
Te
to the first
$$0^{+}_2$$
0
2
+
excited state of
$$\mathrm {^{130}Xe}$$
130
Xe
: the
$$0\nu \beta \beta $$
0
ν
β
β
decay and the Standard Model-allowed two-neutrinos double beta decay (
$$2\nu \beta \beta $$
2
ν
β
β
). Both searches are based on a 372.5 kg
$$\times $$
×
yr TeO
$$_2$$
2
exposure. The de-excitation gamma rays emitted by the excited Xe nucleus in the final state yield a unique signature, which can be searched for with low background by studying coincident events in two or more bolometers. The closely packed arrangement of the CUORE crystals constitutes a significant advantage in this regard. The median limit setting sensitivities at 90% Credible Interval (C.I.) of the given searches were estimated as
$$\mathrm {S^{0\nu }_{1/2} = 5.6 \times 10^{24} \, \mathrm {yr}}$$
S
1
/
2
0
ν
=
5.6
×
10
24
yr
for the
$${0\nu \beta \beta }$$
0
ν
β
β
decay and
$$\mathrm {S^{2\nu }_{1/2} = 2.1 \times 10^{24} \, \mathrm {yr}}$$
S
1
/
2
2
ν
=
2.1
×
10
24
yr
for the
$${2\nu \beta \beta }$$
2
ν
β
β
decay. No significant evidence for either of the decay modes was observed and a Bayesian lower bound at
$$90\%$$
90
%
C.I. on the decay half lives is obtained as:
$$\mathrm {(T_{1/2})^{0\nu }_{0^+_2} > 5.9 \times 10^{24} \, \mathrm {yr}}$$
(
T
1
/
2
)
0
2
+
0
ν
>
5.9
×
10
24
yr
for the
$$0\nu \beta \beta $$
0
ν
β
β
mode and
$$\mathrm {(T_{1/2})^{2\nu }_{0^+_2} > 1.3 \times 10^{24} \, \mathrm {yr}}$$
(
T
1
/
2
)
0
2
+
2
ν
>
1.3
×
10
24
yr
for the
$$2\nu \beta \beta $$
2
ν
β
β
mode. These represent the most stringent limits on the DBD of
$$^{130}$$
130
Te to excited states and improve by a factor
$$\sim 5$$
∼
5
the previous results on this process.
The CUORE Detector and Results Nutini, Irene; Adams, D. Q.; Alfonso, K. ...
Journal of low temperature physics,
2020/4, Letnik:
199, Številka:
1-2
Journal Article
Recenzirano
Odprti dostop
The cryogenic underground observatory for rare events (CUORE) is a cryogenic experiment searching for neutrinoless double beta decay (
0
ν
β
β
) of
130
Te
. The detector consists of an array of
988
...TeO
2
crystals arranged in a compact cylindrical structure of 19 towers. We report the CUORE initial operations and optimization campaigns. We then present the CUORE results on
0
ν
β
β
and
2
ν
β
β
decay of
130
Te
obtained from the analysis of the physics data acquired in 2017.
CUORE Upgrade with Particle IDentification (CUPID) is a foreseen ton-scale array of Li
2
MoO
4
(LMO) cryogenic calorimeters with double readout of heat and light signals. Its scientific goal is to ...fully explore the inverted hierarchy of neutrino masses in the search for neutrinoless double beta decay of
100
Mo. Pile-up of standard double beta decay of the candidate isotope is a relevant background. We generate pile-up heat events via injection of Joule heater pulses with a programmable waveform generator in a small array of LMO crystals operated underground in the Laboratori Nazionali del Gran Sasso, Italy. This allows to label pile-up pulses and control both time difference and underlying amplitudes of individual heat pulses in the data. We present the performance of supervised learning classifiers on data and the attained pile-up rejection efficiency.
Latest Results from the CUORE Experiment Nutini, I.; Adams, D. Q.; Alfonso, K. ...
Journal of low temperature physics,
12/2022, Letnik:
209, Številka:
5-6
Journal Article
Recenzirano
Odprti dostop
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first cryogenic experiment searching for
0
ν
β
β
decay that has been able to reach the one-tonne mass scale. The detector, located ...at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, consists of an array of 988
TeO
2
crystals arranged in a compact cylindrical structure of 19 towers. CUORE began its first physics data run in 2017 at a base temperature of about 10 mK and in April 2021 released its
3
rd
result of the search for
0
ν
β
β
, corresponding to a tonne-year of
TeO
2
exposure. This is the largest amount of data ever acquired with a solid state detector and the most sensitive measurement of
0
ν
β
β
decay in
130
Te
ever conducted . We present the current status of CUORE search for
0
ν
β
β
with the updated statistics of one tonne-yr. We finally give an update of the CUORE background model and the measurement of the
130
Te
2
ν
β
β
decay half-life and decay to excited states of
130
Xe
, studies performed using an exposure of 300.7 kg yr.
The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution – comparable to semiconductor ...detectors – and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. In this work, a brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined.
The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution – comparable to semiconductor ...detectors – and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. In this work, a brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined.
Abstract The CUPID Collaboration is designing a tonne-scale, background-free detector to search for double beta decay with sufficient sensitivity to fully explore the parameter space corresponding to ...the inverted neutrino mass hierarchy scenario. One of the CUPID demonstrators, CUPID-Mo, has proved the potential of enriched Li $$_{2}$$ 2 $$^{100}$$ 100 MoO $$_4$$ 4 crystals as suitable detectors for neutrinoless double beta decay search. In this work, we characterised cubic crystals that, compared to the cylindrical crystals used by CUPID-Mo, are more appealing for the construction of tightly packed arrays. We measured an average energy resolution of ( $$6.7\pm 0.6$$ 6.7 ± 0.6 ) keV FWHM in the region of interest, approaching the CUPID target of 5 keV FWHM. We assessed the identification of $$\alpha $$ α particles with and without a reflecting foil that enhances the scintillation light collection efficiency, proving that the baseline design of CUPID already ensures a complete suppression of this $$\alpha $$ α -induced background contribution. We also used the collected data to validate a Monte Carlo simulation modelling the light collection efficiency, which will enable further optimisations of the detector.
We report new results from the search for neutrinoless double-beta decay in $^{130}$Te with the CUORE detector. This search benefits from a four-fold increase in exposure, lower trigger thresholds ...and analysis improvements relative to our previous results. We observe a background of $(1.38\pm0.07)\cdot10^{-2}$ counts$/($keV$\cdot$kg$\cdot$yr$)$ in the $0\nu\beta\beta$ decay region of interest and, with a total exposure of 372.5 kg$\cdot$yr, we attain a median exclusion sensitivity of $1.7\cdot10^{25}$ yr. We find no evidence for $0\nu\beta\beta$ decay and set a $90\%$ CI Bayesian lower limit of $3.2\cdot10^{25}$ yr on the $^{130}$Te half-life for this process. In the hypothesis that $0\nu\beta\beta$ decay is mediated by light Majorana neutrinos, this results in an upper limit on the effective Majorana mass of 75-350 meV, depending on the nuclear matrix elements used.
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