Results from the CUORE experiment CUORE Matteo Biassoni on behalf of - - PowerPoint PPT Presentation

▶
results from the cuore experiment
SMART_READER_LITE
LIVE PREVIEW

Results from the CUORE experiment CUORE Matteo Biassoni on behalf of - - PowerPoint PPT Presentation

Aug 07, 2023 557 likes •924 views

Results from the CUORE experiment CUORE Matteo Biassoni on behalf of the CUORE Collaboration INFN - Sez. Milano Bicocca M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

slide-1
SLIDE 1

Results from the CUORE experiment

Matteo Biassoni on behalf of the CUORE Collaboration INFN - Sez. Milano Bicocca CUORE

  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019
slide-2
SLIDE 2
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 2

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-3
SLIDE 3
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 3

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-4
SLIDE 4
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 4

TeO2 and thermal detectors for 0νDBD

Second order nuclear process, alternative to beta decay forbidden by mass difference for some even-even nuclei

(A, Z) → (A, Z + 2) + 2e− (A, Z) → (A, Z + 2) + 2e− + 2¯ νe

2nd order SM process, T1/2 ~1018~24 years

  • SM forbidden, ΔL = 2
  • if observed, then neutrino is a

Majorana particle

  • underlying mechanism can give insight

into beyond SM physics

  • light neutrino mass scale and

hierarchy

  • heavy neutrino
  • …

Thermal detectors are a good choice for 0νDBD search:

  • excellent energy resolution
  • large active mass and

efficiency/unit cost

  • fully active source and sensitive

volume, no dead-layer

130Te is a good candidate source

for 0νDBD search:

  • high natural isotopic

abundance (~34%)

  • NME and phase space on

average

  • Q-value (2528 keV) above

most of the natural radioactivity

  • easy to mix in convenient

chemical compounds (TeO2)

slide-5
SLIDE 5
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 5

TeO2 arrays: state of the art

CUORE is the latest in a long progression

  • f TeO2 detectors

which included two large demonstrators:

  • Cuoricino

(2.8x1024 y)

  • CUORE-0

(4.0x1024 y combined)

Running period

1990 1995 2000 2005 2010 2015 2020 2025

t0ν

1 /2

[yr]

(90% C. L.) 1019 1020 1021 1022 1023 1024 1025 1026

6 g 21 g 34 g 73 g 334 g 4 crystal array MiDBD Cuoricino CUORE-0 CUORE

slide-6
SLIDE 6
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 6

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-7
SLIDE 7
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 7

CUORE

Detector design: closely packed array of 988 TeO2 crystals arranged in 19 towers CUORE projected sensitivity (5 years, 90% C.L.): T1/2 > 9 × 1025 yr

Cryogenic Underground Observatory for Rare Events Primary goal: search for 0νββ decay in 130Te

Design parameters:

  • mass of TeO2: 742 kg (206 kg of 130Te )
  • low background aim: 10-2 c/(keV⋅kg⋅yr)
  • target energy resolution: 5 keV FWHM in the Region Of

Interest (ROI)

  • high granularity
  • deep underground location
  • strict radio-purity controls on materials and assembly
slide-8
SLIDE 8
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 8

The CUORE Collaboration

slide-9
SLIDE 9
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 9

CUORE @ LNGS

1400 m of rock (~3600 m.w.e.) deep

  • μ’s: ~3 × 10-8 / (s⋅cm2)
  • γ’s: ~0.73 / (s⋅cm2)
  • neutrons: 4 × 10-6 /(s⋅cm2) below 10 MeV
slide-10
SLIDE 10
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 10

CUORE

CUORE @ LNGS

slide-11
SLIDE 11
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 11

Minus-K isolators Support columns External lead shield (~70 t) Concrete walls Seismic isolators Y beam Main Support Plate Cryostat H3BO3 panels Polyethylene Screw jacks Movable platform

  • Three-story building
  • Hosting the cryostat supporting structure

Underground Laboratory

slide-12
SLIDE 12
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 12

The CUORE cryostat

Detector Towers Top Lead Shield Side Lead Shield 300 K 40 K 4 K 600 mK 50 mK 10 mK Boom Lead Shield Plates:

Challenges:

  • Cool down ~1 ton detector to ~10 mK
  • Mechanically decoupled for extremely low vibrations
  • Low background environment
  • Large duty cycle and long term stability
  • Cryogen-free cryostat
  • Fast Cooling System (4He gas) down to ~50K
  • 5 pulse tubes cryocooler down to ~4K
  • Dilution refrigerator down to operating temperature ~10 mK
  • Nominal cooling power: 3 μW @ 10mK
  • Cryostat total mass ~30 tons
  • Mass to be cooled < 4K: ~15 tons
  • Mass to be cooled < 50 mK: ~3 tons (Pb, Cu and TeO2)
slide-13
SLIDE 13
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 13

Detector calibration system

Challenges:

  • Provide a uniform calibration of all the CUORE detectors
  • Deployment of thoriated strings through the cryostat, from room

temperature into the detector core

  • 8 additional tubes can host strings outside the 300K vessel but

inside the lead shielding

  • J. S. Cushman et al. The detector calibration system for the CUORE cryogenic bolometer array. Nuclear

Instruments and Methods A 844, 32-44 (2017). arxiv:1608.01607

300 K 4 K Lead Inner string Outer string

Inner strings Outer strings External calibration

slide-14
SLIDE 14
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 14

Passive shielding

Challenges:

  • Protect the detectors with a heavy shield against gamma and

neutron activity from external sources (~70 tonnes lead + H3BO3)

  • Select materials that don’t contribute themselves to the

background level (ancient roman lead and selected NOSV copper)

  • Cool down inner layers of the shielding to the correct

temperature (2.5 tonnes @ 50mK + 5.5 tonnes @ 4K)

slide-15
SLIDE 15
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 15

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-16
SLIDE 16
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 16

CUORE Roadmap

Feb 2016 Aug - Oct 2016 Jan 2017 Mar - Apr 2017

Cryostat Commissioning

  • 8-channels functioning

mock-up detector

  • Noise study and

mitigation

  • Stable base

temperature < 7 mK

  • Calibration sources

deployment Detector Cool down

  • 300 K —> 4 K in

22 days

  • 4 K —> 7 mK in

3.5 days

  • First pulses seen

just after cool- down

∆t [d]

0.5 1 1.5 2 2.5 3 3.5 4

T [K]

0.01 0.1 1 10 Still plate HEX plate MC plate CUORE cool down

Start: 2017-01-23 10:00

Detector Installation

  • Radon-free

environment

  • 1 tower/day, 3
  • perators
  • Read-out testing
  • Cryostat interfaces
  • Inner radiation

shields Detector pre-operation

  • Optimisation of all sub-systems
  • Working temperature and working point

selection

  • Noise reduction
slide-17
SLIDE 17
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 17

CUORE Roadmap

Nov - Mar 2017 Jul - Fall 2018

First period of Science Data taking

  • 2 Datasets
  • 984/988 operational channels
  • 86.3 kg*y exposure
  • Most sensitive search for 0νββ

in 130Te to date

May - Sep 2017

Partial warm up

  • Fix small leak in

the cryostat region

  • Warmed up to

100 K Second period of Science Data taking

  • 2 Datasets
  • 984/988 operational channels
  • New optimised working

temperature

  • New working points
  • PT noise reduction
  • Resolution in new data unchanged
  • More then doubled the statistics
  • Updated physics results coming

soon

Reconstructed Energy (keV)

500 1000 1500 2000 2500 3000

  • arb. units

10

2

10

3

10

4

10

5

10

CUORE Preliminary

Dataset 2 Dataset 3

Winter 2018/2019 March 2019

Third period of Science Data taking

  • Cool down to base temperature ongoing
  • Initial calibration to begin soon
  • Largely improved cryostat and detector stability
  • Increased duty cycle
  • Thresholds lowered with Optimum Filter-based

trigger algorithm

  • Refined event reconstruction algorithm to

reduce correlated noise and improve energy resolution Warm up and major maintenance

  • Warmed up to 100 K
  • Cleaned 3He-4He line from air

that prevented stable circulation

  • Improved mixture circuit to

reduce leaks and increase long term stability

  • Added external calibration system

to reduce dead time due to strings deployment

  • Fixed leaking pulse tubes to

reestablish redundancy

  • Ordinary maintenance of pumps
slide-18
SLIDE 18
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 18

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-19
SLIDE 19
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019

Reconstructed Energy (keV) 500 1000 1500 2000 2500 Counts / (keV kg yr) 500 1000 1500 2000 2500 3000

CUORE

  • Phys. Rev. Lett. 120, 132501 (2018)

239 338 583 911 969 2615

19

Calibration spectrum

  • Calibration strings deployed

inside and outside the CUORE detector (Th and Co)

  • Summed energy spectrum of

all the CUORE detectors- datasets

  • Calibration data used for:
  • energy scale calibration
  • thermal gain stabilisation
  • detector response (line

shape) study

239 keV - 212Pb 338, 911, 969 keV - 228Ac 583, 2615 keV - 208Tl

slide-20
SLIDE 20
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 20

Energy resolution

@ 2615 keV ds3018: 9.0 keV FWHM ds3021: 7.4 keV FWHM effective (exposure-weighted): 8.0 keV FWHM

FWHM (keV) 10 20 30 40 50 Channels 50 100 150 200 250 300 350

Calibration resolution at 2615 keV

CUORE

  • Phys. Rev. Lett. 120, 132501 (2018)

@ Q-value ds3018: (8.3 ± 0.4) keV FWHM ds3021: (7.4 ± 0.7) keV FWHM effective (exposure-weighted): (7.7 ± 0.5) keV FWHM

2570 2580 2590 2600 2610 2620 2630 2640 2650 2660

) σ Residual (

2 − 1 − 1 2 3

Reconstructed Energy (keV) 2570 2580 2590 2600 2610 2620 2630 2640 2650 2660 Counts / (2 keV) 20 40 60 80 100

CUORE

yr ⋅ Exposure: 86.3 kg

  • Phys. Rev. Lett. 120, 132501 (2018)
slide-21
SLIDE 21
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019

  • Base quality cuts (number of pulses in the window, baseline stability, etc…)
  • Anti-coincidence
  • Pulse shape analysis: deformed events are not used to build the final spectra to avoid

spectral shape distortions

21

Event selection

Event selection occurs after periods of low-quality data (~1% of the total live time) are removed.

M1 - 0νββ/2νββ signal like M2 - rejected background and important information for bkg studies M1 - dangerous background

e- e- α ɣ ɣ α

slide-22
SLIDE 22
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 22

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-23
SLIDE 23
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 23

Fit in the 0νDBD ROI

Region of interest: 2465 to 2575 keV Overall signal efficiency: (75.7 ± 3.0)% - ds3018 (83.0 ± 2.6)% - ds3021 Events in the region of interest: 155 ROI background index: (1.49–0.17+0.18) × 10-2 c/(keV⋅kg⋅yr) (1.35–0.18+0.20) × 10-2 c/(keV⋅kg⋅yr) Best fit for 60Co mean: (2506.4 ± 1.2) keV Best fit decay rate: (-1.0–0.3+0.4 (stat.) ± 0.1 (syst.))×10-25 / yr

2480 2500 2520 2540 2560

2 − 1 − 1 2 3

) σ Residual (

2480 2500 2520 2540 2560 Reconstructed Energy (keV) 2 4 6 8 10 12 14 16 Counts / (2.5 keV)

Co

60 β β

Q

CUORE

yr ⋅ Exposure: 86.3 kg

  • Phys. Rev. Lett. 120, 132501 (2018)

Decay rate limit (90% CL, including systematics): 0.51 × 10-25 / yr Half-life limit (90% CL, including systematics): 1.3 × 1025 yr Median expected sensitivity: 7.0 × 1024 yr No evidence of signal CUORE, CUORE-0 and CUORICINO combined 90% C.L. limit is T0ν > 1.5 × 1025 yr

  • Phys. Rev. Lett. 120, 132501 (2018)
slide-24
SLIDE 24
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 24

Combination with previous 0νDBD results

NME:

JHEP02 (2013) 025

  • Nucl. Phys. A 818, 139 (2009)
  • Phys. Rev. C 87, 045501 (2013)
  • Phys. Rev. C 87, 064302 (2014)
  • Phys. Rev. C 91, 034304 (2015)
  • Phys. Rev. C 91, 024613 (2015)
  • Phys. Rev. C 91, 024309 (2015)
  • Phys. Rev. C 91, 024316 (2015)
  • Phys. Rev. Lett. 105, 252503 (2010)
  • Phys. Rev. Lett. 111, 142501 (2013)

Experiments:

130Te: 1.5 × 1025 yr from PRL 120, 132501 (2018) 76Ge: 8.0 × 1025 yr from PRL 120, 132503 (2018) 136Xe: 1.1 × 1026 yr from Phys. Rev. Lett. 117, 082503 (2016) 100Mo: 1.1 × 1024 yr from Phys. Rev. D 89, 111101 (2014)

CUORE sensitivity: 9.0 × 1025 yr

  • Total 130Te exposure
  • 86.3 kg·yr of CUORE
  • 19.75 kg·yr of Cuoricino
  • 9.8 kg·yr of CUORE-0
  • The combined 90% C.L. limit is

T0ν > 1.5 × 1025 yr mββ < 110-520 meV

(meV)

lightest

m

1 −

10 1 10

2

10 (meV)

β β

m

1 −

10 1 10

2

10

3

10

+ CUORE limit (Te), PRL 2018 Cuoricino + CUORE-0 CUORE sensitivity (Te) Normal hierarchy Inverted hierarchy

1

1 10

2

10

3

10

Other isotopes Mo Ge Xe

slide-25
SLIDE 25
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 25

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-26
SLIDE 26
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 26

CUORE Background Model

α background mostly consistent with CUORE-0 (as expected) ɣ background significantly reduced

slide-27
SLIDE 27
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 27

CUORE Background Model

210Po excess still under investigation:

  • appears to be from surface contamination in copper around the detector
  • estimated contribution to ROI ~ 10-4 ckky (~1%)
slide-28
SLIDE 28
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 28

CUORE Background Model

DATA

  • 86.3 kg yr of TeO2, same data used for 0νDBD analysis
  • split data into inner and outer (2 crystals thick) layers
  • outer layers more sensitive to external backgrounds
  • split data into Multiplicity 1, Multiplicity 2 and Multiplicity 2 Sum
  • different multiplicities are sensitive to different types of backgrounds
slide-29
SLIDE 29
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 29

CUORE Background Model

MONTE CARLO

  • ~60 independent simulations of sources/location in the setup
  • full radioactive chains and single isotopes
  • the different energy spectra (inner/outer, M1/M2,M2sum) of each source/

location are generated with Geant4 based simulation implementing a detailed geometry of the setup (detector, cryostat, shields)

slide-30
SLIDE 30
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 30

CUORE Background Model

MONTE CARLO

  • ~60 independent simulations of sources/location in the setup
  • full radioactive chains and single isotopes
  • the different energy spectra (inner/outer, M1/M2,M2sum) of each source/

location are generated with Geant4 based simulation implementing a detailed geometry of the setup (detector, cryostat, shields) DATA

  • 86.3 kg yr of TeO2, same data used for 0νDBD analysis
  • split data into inner and outer (2 crystals thick) layers
  • outer layers more sensitive to external backgrounds
  • split data into Multiplicity 1, Multiplicity 2 and Multiplicity 2 Sum
  • different multiplicities are sensitive to different types of backgrounds
  • Assign to each ingredient (source/location) a

normalisation factor

  • Assign a prior to each normalisation factor

from material screening, assays and cosmogenic analysis

  • Fit the model to the data and sample the

posteriors with MCMC Gibbs sampler

BAYESIAN FIT

slide-31
SLIDE 31
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 31

CUORE Background Model

BAYESIAN FIT

1000 2000 3000 4000 5000 6000 7000 Energy (keV)

1 −

10 1 10

2

10 Counts/keV

CUORE Preliminary

yr ⋅ Exposure: 86.3 kg Experimental JAGS reconstruction

Multiplicity 1 - Inner layer 1000 2000 3000 4000 5000 6000 7000

Energy (keV)

0.5 1 1.5 2 2.5

Data/Model ratio

Data/Model σ 1 σ 2 σ 3

slide-32
SLIDE 32
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 32

Outline

  • TeO2 and thermal detectors for neutrino-less DBD
  • CUORE setup
  • Location
  • Cryogenic system
  • Calibration system
  • Shielding
  • CUORE roadmap
  • Analysis procedures
  • Calibration and detector response
  • Event selection and topology
  • Physics results
  • 0νββ and lepton number violation
  • background model
  • 2νββ
  • Conclusions and outlook
slide-33
SLIDE 33
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 33

2νDBD

2νDBD spectrum is one of the ingredients in the background model CUORE-0: ~ 20% of counts in 1-2 MeV region

  • lower background
  • self-shielding
  • anti-coincidence efficiency

CUORE: ~ 100% of counts in 1-2 MeV region

500 1000 1500 2000 2500 Energy (keV)

1 −

10 1 10

2

10

3

10 Counts / keV β β ν 2

2

K in TeO

40

Experimental data

CUORE Preliminary

yr ⋅ Exposure: 86.3 kg

Multiplicity 1 - Inner layer

slide-34
SLIDE 34
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 34

2νDBD

2νDBD spectrum is one of the ingredients in the background model CUORE: ~ 100% of counts in 1-2 MeV region

500 1000 1500 2000 2500 Energy (keV)

1 −

10 1 10

2

10

3

10 Counts / keV β β ν 2

2

K in TeO

40

Experimental data

CUORE Preliminary

yr ⋅ Exposure: 86.3 kg

Multiplicity 1 - Inner layer

0.76 0.78 0.8 0.82

21

10 × half-life [yr] β β ν 2 0.02 0.04 0.06 0.08 0.1 Marginal p.d.f.

CUORE Preliminary

yr ⋅ Exposure: 86.3 kg

posterior β β ν 2

slide-35
SLIDE 35
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 35

2νDBD

2νDBD spectrum is one of the ingredients in the background model CUORE: ~ 100% of counts in 1-2 MeV region

500 1000 1500 2000 2500 Energy (keV)

1 −

10 1 10

2

10

3

10 Counts / keV β β ν 2

2

K in TeO

40

Experimental data

CUORE Preliminary

yr ⋅ Exposure: 86.3 kg

Multiplicity 1 - Inner layer

  • Systematic uncertainty dominated by uncertainty on

contaminant location and uniformity

  • studied by repeating the fit with different geometric splitting
  • f the data
  • more data —> finer geometric splitting of the array —>

reduce this component

  • Fit is independent of energy threshold over the range 100 - 750

keV

  • Used M2 data (purer sample of particle events) to improve the

systematic uncertainty on the selection efficiency by one order

  • f magnitude w.r.t. PRL 2018 data release

CUORE − 0 : T 2ν

1/2 = [8.2 ± 0.2(stat.) ± 0.6(syst.)] × 1020yr

NEMO − 3 : T 2ν

1/2 = [7.0 ± 0.9(stat.) ± 1.1(syst.)] × 1020yr

Γ2ν

1/2 = [8.7 ± 0.1(stat.) ± 0.2(syst.)] × 10−22yr−1

T 2ν

1/2 = [7.9 ± 0.1(stat.) ± 0.2(syst.)] × 1020yr

slide-36
SLIDE 36
  • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research

CUORE

Tohoku University, Japan - March 7-9, 2019 36

Conclusions and Outlook

  • With the first two datasets CUORE have:
  • accumulated a total exposure of almost 100 kg⋅y
  • Invaluable operational experience
  • collected important information on detector performance, noise, resolutions, background levels
  • pushed for the first time the limit on neutrino-less double beta decay half life of 130Te beyond 1025 years
  • performed the most precise measure of two-neutrino half life to date
  • The largest and most complex cryogenic experiment is taking

physics data

  • The first analysis efforts were focused on the neutrino-less and

two-neutrino double beta decay of 130Te to GS

  • Physics results on more processes are on their way:
  • Majoron emission, CPTV
  • Dark matter, axions
  • ββ to excited states, β+/EC decays
  • With an unprecedented amount of data, CUORE is the best tool to

study and model the backgrounds for the next generation experiments

  • Data release and physics results with more then doubled statistics

coming soon