1. Neutrino Program in China
Jun CAO
Institute of High Energy Physics, Beijing
Intl. Workshop on Physics Beyond the SM, TDLI, July 1, 2018

2. Programs in China/Outline
Daya Bay Reactor Neutrino Experiment ( )
θ13 and Δm2ee, reactor ν spectrum, exotic searches
JUNO ( )
20 kton LS detector for mass hierarchy, precision measurements, Supernova, DSNB, solar, geo-ν, proton decay, etc.
Participation of Super-K, EXO
Planning
Jinping Neutrino Experiment, for solar and geo-ν (next talk)
0νββ: JUNO-0νββ, PandaX-III, CDEX, GasTPC with SeF6, crystal bolometer.
R&D on ν beam, Xsec measurements.
Participation in intl. programs, e.g. nEXO, LBNF, etc.

3. Frontiers in Neutrino Physics
Neutrino oscillation
CP violation phase
Mass Hierarchy
Precision measurement
Neutrino properties
Direct measurement of mass
Neutrinoless double beta decay
Exotic searches: sterile, magnetic moment, NSI, …
Neutrino astronomy
High energy cosmic neutrino
Supernova, Diffuse SN Background
Solar neutrino
Geo-neutrino
Oscillation Parameters
sin212, sin223, sin213
Δm221, Δm231
δCP

4. Daya Bay
Daya Bay Reactor Neutrino Experiment for θ13. Proposed in 2003, immediately after oscillation established in
China: Civil construction + ~1/2 detector.
US: ~1/2 detector.
Russia, Czech, Hong Kong, and Taiwan all with significant contributions
Dec.24, 2011
Collaboration
41 institutions, 193 collaborators
China (22), US (16), Europe (2), Chile
Aug.15, 2011

5. Oscillation Measurement
Daya Bay announced the non-zero θ13 discovery in 2012
Released 5 results later on. Latest result: 3.4% uncertainty on sin22θ13
1958 d
3.9M ν

6. Reactor Neutrino Spectrum
PRL2016, CPC2017
PRL2017
Found two deviations from models
Flux 5% lower than model
Large excess around 5 MeV (4σ)
Precisely measured the spectrum
Which one of the 4 isotopes contributes to the deviation?
U-235, using fuel evolution
To be understoodJUNO-ND

7. Sterile Neutrino Searches
Best sensitivity in eV2
Combined w/ MINOS, largely excluded the sterile neutrino
Neutron yield measurement, PRD2018
Decoherence (wave packet), EPJC2017
Muon seasonal modulation, JCAP2018
LV and CPTV
Other Studies
PRL2014, PRL2016, PRL2016

8. Daya Bay Planning sin22θ13 Δm2ee
Daya Bay will operate to the end of 2020, confirmed by the funding agency. Measure both sin22θ13 and Δm2ee to <3%.
Most precise measurement on reactor neutrino spectrum.
More exotic searches.
Technical studies for JUNO with one Daya Bay detector: liquid scintillator optimization and low bkg studies
sin22θ13
Stopped
Δm2ee
Stop
Running to 2020

9. JUNO Jiangmen Underground Neutrino Observatory
proposed in 2008 for mass hierarchy
approved in Feb. 2013
~ 300 M$ (+10% intl.)
Data taking in 2021
20 kton LS detector
3% energy resolution
700 m underground
Taishan NPP GW
Guang Zhou
Daya Bay
Hong Kong
JUNO
53 km
Dongguan
Yangjiang NPP
17.4 GW

10. Stainless steel latticed shell: ID40.1m
JUNO Detector
Electronics
Calibration
Top Tracker
Filling +
Overflow
Central detector
SS latticed shell
Acrylic Sphere:
ID: 35.4m
Thickness:120mm
SSLS:
ID: 40.1m
OD: 41.1m
Water pool
ID: 43.5m
Height: 44m
Water Depth: 43.5m
Acrylic sphere
(20 kt LS)
Acrylic sphere : ID35.4m
Pool Depth: 44m
” PMT
’’ PMT
Stainless steel latticed shell: ID40.1m
Water Cherenkov
~ ’’ PMT
Pool ID:43.5m

11. Neutrino Physics with JUNO
Mass Hierarchy w/ reactor: 3-4σ in 6 years
Large chance to be the 1st MH measurement at 3σ
Precision w/ reactor: sin212, Δm221, Δm231 to <1%
Supernova Burst: 5k events + Neutral current
Diffuse SN Background: Discovery potential
Geo-neutrino: Determine Geo-physics model
Proton Decay: Best in K channel
Solar
Atmospheric
Sterile
Neutrino from Dark Matter
Exotic searches
JUNO Yellow book J. Phys. G 43,  (2016)

12. Mass Hierarchy 3-4σ in 6 years, 5σ in 10 years NOvA: certain chance
ORCA: 2022 (?)
DUNE: 2026
Hyper-K: 2026
PINGU: 2025 (?)
INO: ?
M. Blennow et al.

13. Precision Measurements
Probing UPMNS unitarity to ~1%
more precise than CKM!
Statistics
+BG
+1% b2b
+1% EScale +1% EnonL
sin2 θ12
0.54%
0.67%
Δm221
0.24%
0.59%
Δm2ee
0.27%
0.44%
0.16%0.24%
0.16%0.27%
0.39%0.54%
E resolution
Correlation among parameters

14. Supernova ν
> 5k events for SN at 10kpc. Measure energy spectra & fluxes of almost all types of neutrinos with liquid scintillator detector.

15. Diffuse Supernova Neutrino
DSNB: Past core-collapse events
Cosmic star-formation rate
Core-collapse neutrino spectrum
Rate of failed SNe
10 Years’ sensitivity

16. Geo-neutrino JUNO 20 kton Jinping 3 kton Zhe’s talk
JUNO will measure the geo-ν flux and U/Th ratio. So far KamLAND and Borexino measured ~100 geo-ν, limited by statistics, JUNO will have 400/year
Radioactive heat: different BSE models.
Mantle convection, earth magnetic
Jinping
3 kton
Zhe’s talk

17. JUNO: solar and reactor
Solar Neutrino
Borexino (500 ton)
JUNO (20 kton), Jinping (3 kton), SNO+ (1 kton)
Solar Standard Model: CNO cycle; Metallicity
Vacuum oscillation to MSW
Exotic searches
JUNO: solar and reactor
Jinping

18. Takaaki Kajita, Neutrino2018
Proton Decay
Proton decay: physics at very high energy scale, where neutrino mass/mixing might be related with.
Hyper-K: ~1035 years for eπ0
JUNO: ~21034 years for νK+
Takaaki Kajita, Neutrino2018

19. JUNO Collaboration 72 institutions, 580 collaborators
China (30), Taiwan(3), Thailand (3), Pakistan, Armenia
Italy (8), Germany (7), France (5), Russia (3), Belgium, Czech, Finland, Latvia, Slovakia
Brazil (2), Chile (2), USA (2)

20. Civil Construction Progress
Finish the above-floor part of EH in Finish all civil in 2019.

21. State-of-Art LS Detector
Daya Bay
BOREXINO
KamLAND
JUNO
Target Mass
~20 t
~300 t
~1 kt
~20 kt
Photoelectron Yield (PE/MeV)
~160
~500
~250
~1200
Photocathode Coverage
~12%
~34%
~78%
Energy Resolution
~7.5%/√E
~5%/√E
~6%/√E
<3%/√E
Energy Non-linearity
~1.5%
~1%
~2%
<1%
Titanic detector
Unprecedented energy resolution (3%）
PMT Coverage 78%
PMT DE > 27%
LS attenuation length > 20 m
Minimize the optical loss due to detector material.
Calibration
Low background (e.g. 1 ppt for acrylic, or for LS)

22. Major Breakthroughs – MCP-PMT
New type of 20-inch PMT based on MCP
Started PMT R&D in 2008, chose MCP-PMT in 2009 (Patented by Y.F.Wang, S. Qian, T.C.Zhao, J. Cao in China, US, Russia, Japan, EU)
2013: 8” prototypes
2014: 20” prototype, PDE 15%
2015: Prototype PDE 26%, tender: 15k MCP, 5k Dynode
2016: Production line
2017: Batch average PDE 25% in March, 27% in April. 3.6k produced
2018: 6k produced. Recent batch of 300 PMTs average PDE 30%
First 1300 tested at JUNO
Type
# PMTs
PDE
MCP
1354
27.3%
Dynode
1229
28.6%

23. Key Progress – Acrylic, LS
35.4-m Acrylic Vessel
Solved all technical problems: No standards for construction, high precision curved sheet, anti-seismic, low bkg, fast bonding
Tender in Intl. reviews.
The most transparent Liquid Scintillator (attn. >20 m)
Al2O3 filtration
Distillation (Italy)
Gas tripping (Italy)
Water extraction
3x8x0.12m sheet
20 ton pilot plant at DYB
LAB (solvent)
LS (0.5g/L)
LS (3g/L)
Attn len
25 m
23.8 m
20.5 m
Fast bonding test

24. Key Progress - Energy Calibration
Sources
γ： 40K, 54Mn, 60Co, 137Cs
e+：22Na, 68Ge
n： 241Am-Be, 241Am- 13C or 241Pu- 13C, 252Cf
All 4 subsystems prototyped and tested

25. JUNO-0νββ
A possible upgrade: neutrinoless double beta decay w/ JUNO detector after MH determination (e.g. 2026)
Load 5 to 50-ton Xenon in LS (also R&D on other isotopes)
Starting R&D on Xenon enrichment w/ a company, aiming at 100 kg/year
CPC41, (2017) Xe

26. Charge Readout Tile Prototype
0νββ Experiments
EXO is one of the most sensitivity 0νββ experiments. IHEP participate in EXO since 2012.
nEXO R&D by IHEP
Charge readout, Ultra-UV reflective cathode
Low temp. ASIC electronics (noise 200 e)
ICP-MS low bkg measurement
Detector simulation & design optimization
Other 0νββ experiments (see Huanzhong’s talk)
Charge Readout Tile Prototype
Test at Stanford
ICP-MS
Analog multiplexing readout

27. Other R&D MOMENT: emerging scenarios, R&D on key tech. (Target)
Participating LBNF in US, working on target, magnets, etc.
Gas TPC prototype for neutrino scattering
JUNO-Near Detector w/ SiPM  Best possible energy resolution
Neutrinos from muon decay
Proton LINAC for ADS ~15 MW
Ideal energy: 300 MeV/150 km
Good Energy resolution & track
Reactor ν spectrum, mag. Moment, θw

28. Thanks! Summary Daya Bay will take data until 2020
sin2213 and m2ee to < 3% precision, best in future 20y?
Most precise reactor ν spectrum, exotic searches
JUNO aims at data taking in 2021.
Mass Hierarchy, precision measurements
World-leading neutrino astrophysics
New experiments JUNO-ND, Jingping, likely Xsec meas. etc
Many 0νββ proposals and R&Ds
Thanks!