Post on 15-May-2022
Neutrino Experiments
Overview
Liangjian WenInstitute of High Energy Physics, CAS
Jun. 7, 2021
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Xing๏ผPhys. Rep. 854(2020)1
Quark and Lepton Mass Spectra
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|๐| =
CKM
Hierarchy!
|๐| =
PMNS
Approximate ฮผ-ฯ symmetry?
Fundamental problem: neutrino absolute masses?Quarks vs. Leptons: A big puzzle of fermion flavor mixings
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Neutrino Mass & Flavor Mixing
M. V. Diwan et al (2016)
๐ฝ๐๐ ~ ๐. ๐โ
๐ฝ๐๐ ~ ๐๐โ
๐ฝ๐๐ ~ ๐๐โ |๐ซ๐๐๐๐ | ~ ๐. ๐ ร ๐๐โ๐ eV๐
๐ซ๐๐๐๐ ~ ๐ ร ๐๐โ๐ eV๐
๐ =1 0 00 ๐23 ๐ 230 โ๐ 23 ๐23
๐13 0 ๐ 13๐โ๐๐ฟ
0 1 0โ๐ 13๐
๐๐ฟ 0 ๐13
๐12 ๐ 12 0โ๐ 12 ๐12 00 0 1
๐๐๐ 0 00 ๐๐๐ 00 0 1
Standard Parameterization of the PMNS Matrix
0ฮฝ2ฮฒ, LNV?
๐ฝ๐๐ ๐ถ๐๐๐๐๐?
Daya Bay dominates the global precision
Daya Bay
Double Chooz RENO
๐๐ ๐๐22๐13
๐ฮ๐
๐๐2
10โ3eV
2
end of DYB data taking @2020.12.12
๐ ๐๐ โ ๐๐ = 1 โ sin2 2๐13 cos2 ๐12 sin2 ฮ31 + sin2 ๐12 sin
2 ฮ32 โ cos4 ๐13 sin2 2๐12 sin
2 ฮ21
โ 1 โ sin2 2๐13 sin2 ฮ๐๐ โ cos4 ๐13 sin
2 2๐12 sin2 ฮ21 ฮ๐๐ = ฮ๐๐๐
2 ๐ฟ
4๐ธ
sin22ฮธ13 uncertainty 3.4%โ2.7% ฮm2ee uncertainty 2.8% โ 2.1%
๐ฌ๐ข๐ง๐๐๐ฝ๐๐ = ๐. ๐๐๐๐ ยฑ ๐. ๐๐๐๐
โ๐๐๐๐ = ๐. ๐๐ ยฑ ๐. ๐๐ ร ๐๐โ๐ eV2
โ๐322 = 2.47 ยฑ 0.07 ร 10โ3 eV2 (NO)
โ๐322 = โ2.58 ยฑ 0.07 ร 10โ3 eV2 (IO)
ฮธ13
Daya Bay
RENO
Double Chooz
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ฮธ12 & ฮm221
SK+SNO fit disfavors the KamLANDbest fit value at ~1.4ฯ (was ~2ฯ)
ฮธ12 : dominated by solar neutrino dataฮm2
21: better measured by reactor
โข Precise measurement of spectrum at the vacuum-to-matter transition region
โข Measurement of Day/Night asymmetry
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ฮธ23 & ฮm232
Run 1-9 analysis: PRD 103, L011101 (2021)
Run 1-10 analysis:โข Upper octant preference
(77.1% prob) from ฮฝe samplesโข Normal ordering preferred at
80.8%
โข Data prefers first octant โข Contours for ฮธ23
significantly more constraining
โข Slight preference for upper octant, normal hierarchy (1.0 ฯ)
๐ฌ๐ข๐ง๐ ๐ฝ๐๐ = ๐. ๐๐โ๐.๐๐+๐.๐๐
โ๐322 = 2.41 ยฑ 0.07 ร 10โ3 eV2 (NO)
ฮธ23 octant significantly affect the NMO determination in atmospheric experiments. 6
ฮธ23 & ฮm232
Run 1-9 analysis: PRD 103, L011101 (2021)
Run 1-10 analysis:โข Upper octant preference
(77.1% prob) from ฮฝe samplesโข Normal ordering preferred at
80.8%
โข Data prefers first octant โข Contours for ฮธ23
significantly more constraining
โข Slight preference for upper octant, normal hierarchy (1.0 ฯ)
๐ฌ๐ข๐ง๐ ๐ฝ๐๐ = ๐. ๐๐โ๐.๐๐+๐.๐๐
โ๐322 = 2.41 ยฑ 0.07 ร 10โ3 eV2 (NO)
ฮธ23 octant significantly affect the NMO determination in atmospheric experiments. 7
โข Best-fit ฮด = 0.82 ฯโข Exclude ฮฮ ฮด = ฯ/2 at >3ฯโข Disfavor NH ฮด = 3ฯ/2 at ~2ฯ
NOฮฝA
โข ฮด = - ฯ/2 favoredโข Large range of values of ฮดCP
around +๐/2 are excluded at 99.7%
T2K
Clear tension existsNOฮฝA + T2K joint analysis is underway
The CP Phase
(Run 1-9)
Alex Himmel @ Neutrino 2020 8
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Fundamental problem: neutrino absolute masses?โข Oscillation experiments sign of m2
31 , ฮดCP = ?, precise PMNS
โข 0ฮฝฮฒฮฒ experiments = ?, effective neutrino mass
โข ฮฒ decay, cosmology โฆ neutrino absolute mass
Xing๏ผPhys. Rep. 854(2020)1
Quark and Lepton Mass Spectra
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โ๐๐๐๐ and โ๐๐๐
๐
interference ()โ๐๐๐
๐ and โ๐๐๐๐
differenceMatter Effect
AtmosphericReactorAccelerator
Future Neutrino Oscillation Experiments
NMO: fundamental ฮฝ property, imply different flavor structure, a model discriminatorStrategy: Complementary NMO determination in neutrino oscillations
Effective Parameters
๐๐๐๐๐ = ๐๐จ๐ฌ๐๐ฝ๐๐๐๐๐๐
๐ + ๐ฌ๐ข๐ง๐๐ฝ๐๐๐๐๐๐๐
๐๐๐๐๐ = ๐ฌ๐ข๐ง๐๐ฝ๐๐๐๐๐๐
๐ + ๐๐จ๐ฌ๐๐ฝ๐๐๐๐๐๐๐
+ ๐๐จ๐ฌ๐น ๐ฌ๐ข๐ง๐ฝ๐๐ ๐ฌ๐ข๐ง๐๐ฝ๐๐๐ญ๐๐ง๐ฝ๐๐๐๐๐๐๐
๐๐๐๐๐ โ |๐๐๐๐
๐ | = ยฑ๐๐๐๐๐ (๐๐จ๐ฌ๐๐ฝ๐๐
โ ๐๐จ๐ฌ๐น ๐ฌ๐ข๐ง๐ฝ๐๐ ๐ฌ๐ข๐ง๐๐ฝ๐๐๐ญ๐๐ง๐ฝ๐๐)
Primary goals: ฮฝ mass ordering (NMO) and CP violation
ฮด CP : matter-antimatter asymmetryStrategy: Compare ๐ท(๐๐ โ ๐๐) and ๐ท( ๐๐ โ ๐๐) at Acc.
Neutrino Telescopes
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Jiangmen Underground Neutrino Observatory
โข 20 kton liquid scintillator, 3% E reso, <1% E scale Uncer.
โข Primary goals: ฮฝ mass ordering (3~4 ฯ, with 6 yrs data) & Precision measurement (<<1%)
โข Rich physics: Supernova/Solar/Geo/Atmosphere neutrinos, nucleon decay
JUNO Physics Book, J. Phys. G43:030401 (2016)JUNO-TAO CDR: arXiv:2005.08745JUNO Physics and Detector, arXiv:2104.02565
Vertical shaft
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ฮฝ mass ordering at JUNO
โข Independent on ฮด CP and ฮธ23
3ฯ sensitivity (6 yrs of data taking)
โข Further improvement with precise โ๐๐๐๐
> 4ฯ (in 6 yrs) if 1% external โ๐๐๐๐
๐ฌ๐ข๐ง๐๐ฝ๐๐ โ๐๐๐๐ ๐ฌ๐ข๐ง๐๐ฝ๐๐ โ๐๐๐
๐ /โ๐๐๐๐
Direct Meas.(Dominant Expts.)
4.7%(SNO)
2.5%(KamLAND)
3.2%(Daya Bay)
2.8%(Daya Bay/T2K/NOvA)
NuFIT 4.0% 2.8% 2.8% 1.1%
JUNO (6 yrs) < 0.6% < 0.6% ~ 10% < 0.6%
โข Precision measurement to two oscillations and related ฮฝ mixing parameters
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โข Mass ordering: 5๐ within the first 2-3 years, thanks to Earthโs matter effectโข CPV discovery if true ฮดCP = -ฯ/2 with ~7 yrs exposure โข CPV discovery for 50% of true ฮดCP values with ~10 yrs exposure
ฮฝ:ฮฝ = 1:1
CP Violation Sensitivity Mass Ordering Sensitivity
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โข Mass ordering: much less sensitivity due to much smaller matter effectsโข CPV discovery if true ฮดCP = -ฯ/2 with ~5 yrs exposureโข CPV discovery for 50% of true ฮดCP values with 5~10 yrs exposure
Reduction of sys. uncertainties has impact to CPV measurement various Near detectors
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โข If NMO is unknown, beam only sensitivity degrades for some values of ฮดCP
โข Atmospheric neutrino: sensitive to NMO due to higher energy and large Earthโs matter effects
โข Combination of beam and atmospheric neutrinos exclude wrong NMO at ~(4-6)๐, depending on ฮธ23 value
10 years with 1.3MW, T2K 2018 systematic error
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KM3NeT
Neutrino Oscillations at Neutrino Telescopes
250k ฮฝ at 8 yrs
3 years of ORCA operation
For both IceCube-Gen2 (PRD 101 032006 (2020)) and ORCA (NeuTel talk), combination with JUNO results can significantly enhance the sensitivity
arXiv:2103.0988
ฮฝฯ appearance normalisation
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Assess the absolute neutrino mass scale
Constraints on absolute neutrino masses Tritium ฮฒ decays (95% C.L.)
๐๐ท < ๐. ๐ ๐๐ (KATRIN)
๐. ๐ ๐๐ (Mainz & Troitzk) Neutrinoless double-ฮฒ decays (90% C.L.)
๐๐ท๐ท < ๐. ๐๐~๐. ๐๐ ๐๐ (KamLAND-Zen)
๐. ๐๐~๐. ๐๐ ๐๐ (EXO-200)๐. ๐๐~๐. ๐๐ ๐๐ (GERDA)
Cosmological observations (95% probability)๐บ < ๐. ๐๐ ๐๐ (Planck, 2018)
๐ฎ = ๐๐ +๐๐ +๐๐ [eV]
Co
smo
logical B
ou
nd
Tritium ฮฒ decays (KATRIN)
Co
smo
logical B
ou
nd
IO
NO
Neutrinoless double-ฮฒ decays
IO
NO
๐๐ฝ = ฮฃ๐ ๐๐๐2๐๐
2 1/2[eV]
๐๐ฝ๐ฝ = ฮฃ๐๐๐๐2๐๐ [eV]
Capozzi et al., 2003.08511
Abazajian et al., 1907.04473
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4-week science run in 2019 (522 hr scanning):
m(ฮฝ)<1.1 eV (90% CL)
coincide with the target sensitivity:0.2 eV (90% CL, 5 yrs)
Phys. Rev. Lett. 123 (2019) 221802
background: 0.55 106 e-
Tritium ฮฒ decays -- KATRIN
3H: super-allowed ฮฒ-decay (T1/2 ~ 12.3 yrs, E0 ~ 18.56 keV)
neutrino mass square m2(ฮฝe)
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Next generation ฮฒ-decay
Targeted sensitivity: 40 meV
30 yrs history of ฮฒ-decay measurement
KATRIN will continue delivering world-leadingsensitivity
Cyclotron Radiation Emission Spectroscopy (CRES)
โข Multi m3ยทyr effective exposureโข High flux atomic tritium sourceโข ~0.1 eV resolutionโข 10-7 field uniformity
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Neutrino-less Double Beta Decay
0ฮฝฮฒฮฒ offers the most sensitive and only feasible probe to determine if neutrinos are Majorana neutrinosโข Discovery of a new type of elementary particlesโข Discovery of LNV: a guide for theoristsโข MajoranaCP Phases
Determining the nature - Dirac or Majorana - of massive neutrinos is one of the most challenging and pressing problems in present day elementary particle physics
Schechter-Valle Theorem (1982) :if a 0 decay happens, there must be an effective Majoranamass term ( is of Majorana nature)
2ฮฝฮฒฮฒ 0ฮฝฮฒฮฒ
Toward ton-scale 0ฮฝฮฒฮฒ experiment
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โข 136Xe (KamLAND-Zen): > 1026 yrs โข 76Ge (GERDA) : > 1.8 x 1026 yrs โข 130Te (CUORE) : > 3.2 x 1025 yrs
โข ~100x improvement in T1/2
โข Covers Inverted ฮฝ-mass ordering region
Present best Limits on T1/2
โข 136Xe (nEXO) : T1/2 > 1028 yrs โข 76Ge (LEGEND-1000) : T1/2 > 1028 yrs โข 130Te (CUPID) : T1/2 > 1027 yrs
Future goal
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Further future: Towards the
1 meV sensitivity of |mฮฒฮฒ|โข Precise determination of the
lightest neutrino mass
โข Constrain (m1, ฯ, ฯ) to a very small parameter space
Cao et al., CPC 44 (2020) 031001
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For a none background-free experiment, use simple counting approach:
Plot remade from CPC 41 (2017) 053001
Driven factors of 0ฮฝฮฒฮฒ Sensitivity
Detector Exposure
Detector Exposure Detector efficiency
Isotope abundance
Background in ROI* For 90% C.L, =1.64
Background Index (B.I.)
After the completion of the
primary physics goals, JUNO
can be upgraded by loading
0ฮฝฮฒฮฒ isotope into LS, for
searching for 0ฮฝฮฒฮฒ (~2030)Isotope mass (ton) <mฮฒฮฒ>, meV
KamLAND-Zen 136Xe 1 61-165
EXO 136Xe 0.2 93-286
nEXO 136Xe 5 7-22
GERDA 76Ge 1 10-40
Majorana 76Ge 1 10-40
SNO+ 130Te 8 19-46
JUNO-ฮฒฮฒ 136Xe 50 4-12
130Te 100-200 2-6 ๏ผ24
~102 tons of 0ฮฝฮฒฮฒ target;
best LS shielding;
excellent energy resolution (3%/โE);
ultra-low background
Future prospect
of JUNO
The most sensitive to
probe the Majorana nature
of neutrinos, aiming at a
sensitivity level of |mฮฒฮฒ|~
meV
Zhao et al., CPC 41 (2017) 053001
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Ambitious goal: Detection of Cosmic Neutrino Background, which can also probe neutrino mass
PTOLEMY โ Another way to probe ฮฝ mass
Relic neutrino capture on -decaying nuclei
1962
Temperature today
Mean momentum today
At least 2 โs cold today
NON-relativistic โs!
Design: PPNP 106 (2019) 120
Physics: JCAP 07 (2019) 047
Challenges:3H amount, low background, energy resolution, โฆ
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Discoveries on Solar-ฮฝ before 2021
7Be-ฮฝ: PRL 101, 091302 (2008)pep-ฮฝ: PRL 108, 051302 (2012)pp-ฮฝ: Nature 562 (2018) 7728CNO-ฮฝ: Nature 587 (2020) 577-582
PRL 89 (2002) 011301
Smoking gun evidence of solar-ฮฝ oscillation by SNOLater talk by Prof. Art McDonaldโTwenty Years of Solar Neutrinos at SNOโ
Borexino discovered 7Be, pep, pp, and CNO neutrinos, and its data allowed to probe the vacuum-matter transition
Current ฮธ12 precision dominated by solar-ฮฝ data(SNO + Super-K)
LMA-MSW
1 s uncertainty
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Solar-ฮฝ after 2021
โข Promising solar-ฮฝ spectroscopy (8B, 7Be, etc.)
โข 8B ฮฝ-e ES: S/B = 60k/30k (10 yrs), Evis > 2 MeV
โข 10-17 g/g LS radio-purity, optimized FV & muon veto
Day-Night-Asymmetry: 0.9% uncertainty
Upturn: test flat Pee >2ฯ if large ๐ฅ๐212 (7.5x10-5 eV2)
โข Simultaneous solar ๐๐ and reactor ๐๐ meas.
โข New flux meas. of 8B-ฮฝ
โข 200 tons 13C
โข Utilize ๐๐-13C CC & ๐-13C NC
130 evts/d/tank, Evis>4.5MeV
Challenge: radiological & cosmogenicbackgrounds
Chin. Phys. C 45 (2021) 023004
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Summary and Outlook
โข Neutrino oscillation experiments have entered the precision
era, and mass ordering and ฮดCP to be solved in 2030s or even
before (for ordering), which allows deep understanding of
leptonic flavor structure.
โข The ultimate goal of neutrino physics is to understand the
origin of neutrino masses. Mass ordering, Majorana nature
and absolute mass are critical paths. Keep eyes on 0ฮฝฮฒฮฒ.
โข Many other important/exciting fields and experiments, e.g.,
astroparticle physics, neutrino cosmology, sterile neutrinos,
etc, are not covered in this talk.
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Thanks!