1. Introduction of the JUNO experiment Yifang Wang Institute of High Energy Physics Shanghai, May 29, 2014

2. Neutrino Oscillation  Neutrino oscillation:  What is next:  Neutrino mass hierarchy ?  Unitarity of neutrino mixing matrix ？  Θ 23 is maximized ?  CP violation in the neutrino mixing matrix as in the case of quarks ? Large enough for the matter-antimatter asymmetry in the Universe ?  Known parameters ：  23  12        Recent progress:  13  Unknown parameters: MH(    ),  2016-2-20 2 Daya Bay: PRL112(2014)061801

3. The JUNO Experiment Daya Bay 60 km Daya Bay II KamLAND  20 kton LS detector  3% energy resolution  Rich physics possibilities  Mass hierarchy  Precision measurement of 4 mixing parameters  Supernovae neutrinos  Geoneutrinos  Sterile neutrinos  Atmospheric neutrinos  Exotic searches Talk by Y.F. Wang at ICFA seminar 2008, Neutel 2011; by J. Cao at Nutel 2009, NuTurn 2012 ; Paper by L. Zhan, Y.F. Wang, J. Cao, L.J. Wen, PRD78:111103,2008; PRD79:073007,2009

4. Location of JUNO NPPDaya BayHuizhouLufengYangjiang Taishan StatusOperationalPlanned Under construction Power17.4 GW 18.4 GW Yangjiang NPP Taishan NPP Daya Bay NPP Huizhou NPP Lufeng NPP 53 km Hong Kong Macau Guang Zhou Shen Zhen Zhu Hai 2.5 h drive Kaiping, Jiang Men city, Guangdong Province 4 Previous site candidate Overburden ~ 700 m by 2020: 26.6 GW

5. – LS volume:  20  for more statistics (40 events/day) – light(PE)  5  for better resolution (  M 2 12 /  M 2 23 ~ 3%) The plan: a large LS detector 20 kt LS Acrylic tank ：  34.5m Stainless Steel tank ：  37.5m Muon detector Water seal ~15000 20” PMTs coverage: ~80% Steel Tank 6kt MO 20kt water 1500 20” VETO PMTs 2016-2-20 5

6. Mass Hierarchy at Reactors  M 2 23 L. Zhan et al., PRD78:111103,2008; PRD79:073007,2009

7.  12 osc. maximum Yangjiang NPP Taishan NPP 53 km 7 Optimum baseline for MH Optimum at the oscillation maximum of  12 Multiple reactors may cancel the oscillation structure – Baseline difference cannot be more than 500 m Y.F Li et al, PRD 88, 013008 (2013) Daya Bay NPP Huizhou NPP

8. Energy scale can be self-calibrated 2016-2-20 8 If we have a residual non-linearity: by introduce a self-calibration(based on  M 2 ee peaks): effects can be corrected and sensitivity is un-affected

9. Physics Reach 2016-2-20 9 Thanks to a large θ 13 For 6 years ，  Ideally ， The relative measurement can reach a sensitivity of 4  ， while the absolute measurement (with the help of Δm 2   ) can reach 5   Due to reactor core distributions, relative measurement can reach a sensitivity of 3 , while the absolute measurement can reach 4  Detector size: 20kt Energy resolution: 3%/  E Thermal power: 36 GW Y.F. Li et al., arXiv:1303.6733

10. Precision measurement of mixing parameters  Fundamental to the Standard Model and beyond  Probing the unitarity of U PMNS to ~1% level !  Uncertainty from other oscillation parameters and systematic errors, mainly energy scale, are included CurrentDaya Bay II  m 2 12 3%3%0.6%  m 2 23 5%5%0.6% sin 2  12 6%6%0.7% sin 2  23 10%N/A sin 2  13 14%  4% ~ 15% Will be more precise than CKM matrix elements !

11. Supernova neutrinos in Giant LS detector Less than 20 events observed so far Assumptions: – Distance: 10 kpc (our Galaxy center) – Energy: 3  10 53 erg – L the same for all types LS detector vs. Water Cerenkov detectors: much better detection to these correlated events  Measure energy spectra & fluxes of almost all types of neutrinos Estimated numbers of neutrino events in JUNO (preliminary) 11 event spectrum of -p scattering (preliminary) Possible candidate

12. Other Physics with Giant LS detector Geo-neutrino s – Current results: KamLAND: 30±7 TNU (PRD 88 (2013) 033001) Borexino: 38.8±12.0 TNU (PLB 722 (2013) 295) – Desire to reach an error of 3 TNU: statistically dominant – JUNO: ×10 statistics Huge reactor neutrino backgrounds Expectation: ? ±10%±10% Solar neutrinos – need LS purification, low threshold – background handling (radioactivity, cosmogenic) Atmosphere neutrinos Nucleon Decay Sterile neutrinos Stephen Dye @Neutrino 2012 12

13. Central Detector  Some basic numbers:  20 kt liquid scintillator as the target  Signal event rate: 40/day  Backgrounds with 700 m overburden: Accidentals(~10%), 9 Li/ 8 He(<1%), fast neutros(<1%)  A huge detector in a water pool:  Default option: acrylic tank(D~35m) + SS structure  Backup option: SS tank(D~38m) + acrylic structure + balloon  Issues:  Engineering: mechanics, safety, lifetime, …  Physics: cleanness, light collection, …  Assembly & installation  Design & prototyping underway 13

14. MC example ： Energy Resolution  Based on DYB MC (tuned to data), except  JUNO Geometry and 80% photocathode coverage  PMT QE from 25% -> 35%  Attenuation length (1m-tube measurement@430nm) from 15m = abs. 30 m + Rayleigh scatt. 30 m to 20 m = abs. 60 m + Rayleigh scatt. 30m Uniformly Distributed Events After vertex-dep. correction R3R3 total charge-based energy reconstruction with an ideal vertex reconstruction

15. Liquid Scintillator  Requirements & works:  Low background:  No Gd-loading  Current Choice: LAB+PPO+BisMSB  Long attenuation length: 15m  30m Improve raw materials Improve the production process Purification –Distillation, Filtration, Water extraction, Nitrogen stripping…  Highest light yield ： Optimization of fluor concentration  Other works ：  Rayleigh scattering length  Energy non-linearity  Aging  Engineering issues: equipment for 20kt  Raw material selection: BKG & purity issues Linear Alky BenzeneAtte. L(m) @ 430 nm RAW14.2 Vacuum distillation19.5 SiO 2 coloum18.6 Al 2 O 3 coloum22.3 LAB from Nanjing, Raw20 Al 2 O 3 coloum25 KamLAND 15

16. High QE PMT  Three types of high QE 20” PMTs under development:  Hammamatzu R5912-100 with SBA photocathode  A new design using MCP: 4  collection  Photonics-type PMT  MCP-PMT development:  Technical issues mostly resolved  Successful 8” prototypes  A few 20” prototypes 16 SPE Gain R591 2 R5912 -100 MCP -PMT QE@410nm25%35%25% Rise time3 ns 3.4ns 5ns SPE Amp.17mV18mV17mV P/V of SPE>2.5 `2 TTS5.5ns1.5 ns3.5 ns

17. Muon VETO detector 17 2016-2-20 17  Top tracker(Opera target tracker)  Tracker support  Water system  Tyvek  PMT support  Water pool liner  Earth magnetic shielding

18. Readout Electronics and Trigger  Charge and timing info. from 1 GHz FADC  Main Choice to be made: in water or on surface 18 Total No. channel20,000 Event rate ~ 50 KHz Charge precision1 – 100 PE: 0.1 – 1 PE; 100-4000PE: 1-40PE Noise0.1 PE Timing0-2us: ~ 100 ps An option to have a box in water:  ~100 ch. per box  Changeable in water  Global trigger on surface

19. Civil Construction 19 A 600m vertical shaft A 1300m long tunnel(40% slope) A 50m diameter, 80m high cavern

20. Layout 20

21. 21 LS storage, mixing & purification Dorm Tunnel entrance, Assembly  exhibition Un-loading zone Dorm Office & control room Storage

22. Current Status & Brief Schedule  Project approved by CAS for R&D and design  Geological survey completed  Granite rock, tem. ~ 31 o C, little water  EPC contract signed:  Engineering design by July  Construction work by Nov.  Paper work towards the construction:  Land, environment, safety, … 22 Schedule: Civil preparation ： 2013-2014 Civil construction ： 2014-2017 Detector component production ： 2016-2017 PMT production ： 2016-2019 Detector assembly & installation ： 2018-2019 Filling & data taking ： 2020

23. International collaboration  Proto-collaboration since 2013, meeting every 6 months – Italy, Germany, France, Russia, Czech, US, … – Double Chooz, Borexino, LENA, Daya Bay, Hanohano, OPERA, …  Formal collaboration this summer 23

24. Summary JUNO is competitive for measuring MH using reactor neutrinos – Independent of the yet-unknown CP phase and  23 Many other science goals:  Precision measurement of Δm 31 2, θ 12, Δm 21 2  Geo-, solar, supernova, …, neutrinos R&D and design on going, project will start soon 24 NOvA, LBNE:  PINGU, INO:  23 =40-50  JUNO: 3%-3.5% M. Blennow et al., JHEP 1403 (2014) 028

25. Welcome to Kaiping