1. 5th June 2003, NuFact03 Kengo Nakamura1 Solar neutrino results, KamLAND & prospects www.awa.tohoku.ac.jp/~kengo/NuFact03.pdf Solar Neutrino History Solar Neutrino History KamLAND KamLAND Prospects Prospects Kengo Nakamura Duke/TUNL

2. 5th June 2003, NuFact03 Kengo Nakamura2 Solar Neutrino Problem

3. 5th June 2003, NuFact03 Kengo Nakamura3 Cl, Kamiokande,Ga  LMA,SMA,LOW,VAC SuperK day night, SuperK energy spectrum  LMA+ LOW SNO NC; e +  +  Flavor transition SNO day/night  LMA Neutrino Oscillation KamLAND; Man made neutrino sources LMA SMA LOW VAC http://hitoshi.berkeley.edu/neutrino 95%CL

4. 5th June 2003, NuFact03 Kengo Nakamura4 SNO result First direct measurement of active 8 B  Strong evidence for neutrino flavor transition. Total 8 B  agrees with SSM. SNO Day/night + All solar  LMA. Without the constraint on energy (SSM) PRL89(2002)011301

5. 5th June 2003, NuFact03 Kengo Nakamura5 SNO Status Neutron capture on Cl  Large  of neutron capture on Cl  8.6MeV multiple  s  Good light isotropy  Better NC extraction  Result is expected in a few months? Installation of Neutral Current Detector Array  n+ 3 He  p+t  Independent NC measurement(syst.+9.1/-8.5  +/- 4.5 %)  Sept. 03  ? A.Poon I.O.P. HEPP Particle Physics 2003, Durham

6. 5th June 2003, NuFact03 Kengo Nakamura6 KamLAND Kamioka Liquid scintillator Anti Neutrino Detector Reactor Anti Neutrino Source. Reactor Anti Neutrino Source. Energy distortion? under Lab. condition. Energy distortion? under Lab. condition. LMA? LMA? CPT invariance. CPT invariance. 7 Be neutrinos. 7 Be neutrinos. (Evis )

7. 5th June 2003, NuFact03 Kengo Nakamura7 Thermal power, Burn-up, Fuel change record data, Simple model of reactor core.  fission rate  energy spectrum @KamLAND Korea(2.3+- 0.2% @N( ) ) a few /day in KamLAND

8. 5th June 2003, NuFact03 Kengo Nakamura8 KamLAND Detector Evis=E -0.78 MeV 20m 2700m.w.e.

9. 5th June 2003, NuFact03 Kengo Nakamura9 Energy resolution 68 Ge (  +  ) : 1.012 MeV 65 Zn (  ) : 1.116 MeV 60 Co (  +  ) : 2.506 MeV AmBe ( ,n) : 2.20, 4.40, 7.6 MeV n+p  d+  MeV n+ 12 C  13 C+  : 4.9MeV n   E/E ~ 7.5% /√E [MeV]  E syst =1.9% at 2.6MeV  2.1% for anti e spallation

10. 5th June 2003, NuFact03 Kengo Nakamura10 AmBe Neutrons Delayed coincidence effi = 95.3 %Detection effi= 98.8% 660  sec Capture time = 190  sec

11. 5th June 2003, NuFact03 Kengo Nakamura11 Vertex reconstruction 5cm resolution Uniform 2.2MeV  4.1% uncertainty on number of neutrinos coming from fiducial mass ratio

12. 5th June 2003, NuFact03 Kengo Nakamura12    T = |t prompt – t delayed |     214 Po:   s 214 Bi – 214 Po – 210 Pb Signal delayedprompt 238 U = (3.5±0.5)x10 -18 g/g

13. 5th June 2003, NuFact03 Kengo Nakamura13 Radioactive Background in LS

14. 5th June 2003, NuFact03 Kengo Nakamura14

15. 5th June 2003, NuFact03 Kengo Nakamura15 Neutrino Event selection Timing correlation in PMTs no  veto signals 0.5 <  T < 660  sec 1.8 < E delayed < 2.6 MeV R < 5 m : 409 ton, 3.46x10 31 free protons  R 1.2 m Veto for 2msec. after muons. Veto for 2sec. after muons (E>10 6 p.e.) (0.02Hz) Cylindrical (R=3m) 2sec veto around muons (E<10 6 p.e.) tagging efficiency 78.3%  tagging efficiency 78.3% Details

16. 5th June 2003, NuFact03 Kengo Nakamura16 Vertex position after delayed coincidence

17. 5th June 2003, NuFact03 Kengo Nakamura17 Prompt Delayed (n 12 C)

18. 5th June 2003, NuFact03 Kengo Nakamura18 KamLAND result Mar. 4 – Oct. 6, 2002 162 tonyr (145.1 days) Observed 54 events (E>2.6MeV) Background 1 ± 1 events Expected 86.8 ± 5.6 events

19. 5th June 2003, NuFact03 Kengo Nakamura19 KamLAND impacts 95%CL KamLANDAll combined LMA 2 LMA 1

20. 5th June 2003, NuFact03 Kengo Nakamura20 Spectral Distortion? 2- oscillation: best-fit No oscillation, flux suppression Data and best oscillation fit consistent at 93% C.L. Data and scaled no-oscillation shape consistent at 53% C.L Need more reactor neutrino and calibration data

21. 5th June 2003, NuFact03 Kengo Nakamura21 KamLAND Prospects Neutrino Oscillation? Precision measurements –Energy Spectrum distortion? –Current reactor power in Japan ~50%. –A new reactor is coming. –LMA 1 or LMA2 7Be –Purification system improvement

22. 5th June 2003, NuFact03 Kengo Nakamura22  2 projection LMA I LMA II

23. 5th June 2003, NuFact03 Kengo Nakamura23 Before and After Shika LMA I LMA II

24. 5th June 2003, NuFact03 Kengo Nakamura24 Solar @ KamLAND No direct observation of 7 Be  Improve KamLAND purification system. 210 Pb; 10 -20 g/g  10 -25 g/g (Water extraction) Air tight valve housings. Testing the water extraction.

25. 5th June 2003, NuFact03 Kengo Nakamura25 Expected

26. 5th June 2003, NuFact03 Kengo Nakamura26 XMASS

27. 5th June 2003, NuFact03 Kengo Nakamura27 Summary Last year – 8 B neutrino measurement and strong evidence of neutrino flavor transition by SNO. –KamLAND observed a clear deficit in reactor neutrinos. Current Status related to KamLAND and SNOCurrent Status related to KamLAND and SNO –SNO cl results coming soon and new NC detector installation. –KamLAND stable n data taking during reactor shutdown. Future –KamLAND update results. –KamLAND purification system will be improved for 7 Be Solar neutrino detection.

28. 5th June 2003, NuFact03 Kengo Nakamura28 Backup slides

29. 5th June 2003, NuFact03 Kengo Nakamura29 How to calculate neutrino flux from reactors

30. 5th June 2003, NuFact03 Kengo Nakamura30 Solar Neutrino at KamLAND

31. 5th June 2003, NuFact03 Kengo Nakamura31 Matter effect

32. 5th June 2003, NuFact03 Kengo Nakamura32  13 The KamLAND is actually measuring;

33. 5th June 2003, NuFact03 Kengo Nakamura33 Trigger efficiency

34. 5th June 2003, NuFact03 Kengo Nakamura34

35. 5th June 2003, NuFact03 Kengo Nakamura35  2 projection