1. NEUTRINO MASSES AND OSCILLATIONS NEUTRINO MASSES AND OSCILLATIONS Triumphs and Challenges R. D. McKeown Caltech

2. Outline Historical introduction Neutrino Oscillations Vacuum Oscillations Matter Oscillations Neutrino Masses The Near Future Outlook

3. 1869 Historical Perspective UPCHARMTOP DOWNSTRANGEBOTTOM ELECTRON e MUON  TAU  1913 ??? 1 2 3

4. New “Periodic Table”

5. Discovery of the Neutrino – 1956 F. Reines, Nobel Lecture, 1995

6. Early History 1936- discovery of the muon (I. Rabi: Who ordered that ??) 1950’s - discovery of ’s at nuclear reactors 1958 – B. Pontecorvo proposes neutrino oscillations 60’s and 70’s – were studied with accelerator experiments e ≠  "All you have to do is imagine something that does practically nothing. You can use your son-in-law as a prototype."

7. More Recent History 1968 – 1 st solar anomaly evidence 1980’s – new interest in neutrino masses and oscillations: ’s as dark matter?? 1980-present: the quest for neutrino oscillations 1998 Super-Kamiokande obtains first evidence for neutrino oscillations

8. Two Generation Model 1.24 (P e  minimum)

9. Length & Energy Scales E = 1 GeV,  m 2 =10 -3 eV 2, L = 1240 km Super-K!! 1.24 (P e  minimum)

10. 30 kton H 2 0 Cherenkov 11000 20” PMT’s

11. Super-Kamiokande Results Neutrino Oscillation Interpretation  K2K, MINOS   > 0.001

12. Length & Energy Scales E = 1 GeV,  m 2 =10 -3 eV 2, L = 1240 km E = 1 MeV,  m 2 =10 -3 eV 2, L = 1.2 km Super-K Chooz, Palo Verde 1.24 (P e  minimum)

13. Reactor Neutrino Experiments e from n-rich fission products detection via inverse beta decay ( e +p  e + +n) Measure flux and energy spectrum Variety of distances L= 10-1000 m

15. Precise Measurements Flux and Energy Spectrum  ~1-2 %

16. Early Reactor Oscillation Searches 10 3 Distance (m)

17. Enter Long Baseline (180 km) Calibrated source(s) Large detector (1 kton) Deep underground (2700 mwe)

18. Length & Energy Scales E = 1 GeV,  m 2 =10 -3 eV 2, L = 1240 km E = 1 MeV,  m 2 =10 -3 eV 2, L = 1.2 km E = 1 MeV,  m 2 =10 -5 eV 2, L = 125 km Super-K Chooz, Palo Verde 1.24 (P e  minimum)

19. Statistical errors only Designed to test solar neutrino oscillation parameters on Earth (!) KamLAND has a much longer baseline than previous (reactor) experiments

20. Only a few places in the World could host an experiment like KamLAND…

21. KamLAND uses the entire Japanese nuclear power industry as a long­baseline source Kashiwazaki Takahama Ohi

22. Narrow baseline range: 85.3% of signal has 140 km < L < 344 km The total electric power produced “as a by-product” of the ’s is: by-product” of the ’s is: ~60 GW or...~60 GW or... ~4% of the world’s manmade power or…~4% of the world’s manmade power or… ~20% of the world’s nuclear power~20% of the world’s nuclear power

23. Spectrum Distortion

24. KamLAND Detector 1879 1000 Ton (Cosmic veto) (135  m)

25. - R prompt, delayed < 5.5 m - ΔR e-n < 2 m - 0.5 μs < ΔT e-n < 1 ms - 1.8 MeV < E delayed < 2.6 MeV - 2.6 MeV < E prompt < 8.5 MeV Tagging efficiency 89.8% Tagging efficiency 89.8% …In addition: …In addition: - 2s veto for showering/bad μ - 2s veto in a R = 3m tube along track Dead-time 9.7% Dead-time 9.7% Selecting antineutrinos, E prompt >2.6MeV (543.7 ton) 5.5 m fiducial cut Balloon edge

26. Ratio of Measured and Expected e Flux from Reactor Neutrino Experiments Solar :  m 2 = 5.5x10 -5 eV 2 sin 2 2  = 0.833 G.Fogli et al., PR D66, 010001-406, (2002)

27. Measurement of Energy Spectrum

28. Oscillation Effect

29. KamLAND best fit :  m 2 = 7.9 x 10 -5 eV 2 tan 2  = 0.45

31. Solar Neutrino Energy Spectrum

32. More missing neutrinos…

33. Neutrino Oscillations? R orbit “Just So ??? “

34. Length & Energy Scales E = 1 GeV,  m 2 =10 -3 eV 2, L = 1240 km E = 1 MeV,  m 2 =10 -3 eV 2, L = 1.2 km E = 1 MeV,  m 2 =10 -5 eV 2, L = 125 km Super-K Chooz, Palo Verde 1.24 (P e  minimum) E = 1 MeV,  m 2 =10 -11 eV 2, L = 10 8 km

35. Matter Enhanced Oscillation (MSW) Mikheyev, Smirnov, Wolfenstein   

36. Enter SNO… e + d  p + p + e - ( CC ) x + d  p + n + x ( NC ) x + e -  x + e - ( ES )

37. Neutrino Mixing Neutrino Masses Flavor Oscillations +

38. Combined fit with solar neutrino data  m 2 =7.9 +0.6 -0.5 x10 -5 eV 2 tan 2  =0.40 +0.10 -0.07

39. Open circles: combined best fit Closed circles: experimental data

40. RECENT NEWS MiniBOONE refutes LSND! LSND ruled out at 98% confidence

41. Maki – Nakagawa – Sakata Matrix Future Reactor Experiment! CP violation

42. Why so different??? <

43. New “Periodic Table”

44. “Seesaw mechanism” M The Mass Puzzle

45. Why haven’t we seen R ? Extra Dimension All charged particles are on a 3-brane Right-handed neutrinos SM gauge singlet  Can propagate in the “bulk” Makes neutrino mass small (Arkani-Hamed, Dimopoulos, Dvali, March-Russell; Dienes, Dudas, Gherghetta) Barbieri-Strumia: SN1987A constraint  “Warped” extra dimension (Grossman, Neubert) or more than one extra dimensions Or SUSY breaking (Arkani-Hamed, Hall, HM, Smith, Weiner; Arkani-Hamed, Kaplan, HM, Nomura) (From H.Murayama)

46. Baseline ~2km More powerful reactors Multiple detectors → measure ratio The Quest for  13 at the Daya Bay Nuclear Power Plant

47. 4 reactor cores, 11.6 GW 2 more cores in 2011, 5.8 GW Mountains provide overburden to shield cosmic-ray backgrounds Daya Bay nuclear power plant

48. DYB NPP region Location and surroundings 55 km

49. Experiment Layout

50. Detector modules Three zone modular structure: I. target: Gd-loaded scintillator II. g-catcher: normal scintillator III. Buffer shielding: oil Reflector at top and bottom 192 8”PMT/module Photocathode coverage: 5.6 %  12%(with reflector) 20 t Gd-LS LS oil Target: 20 t, 1.6m g-catcher: 20t, 45cm Buffer: 40t, 45cm

51. Sensitivity to Sin 2 2q 13 Experiment construction: 2008-2010 Start acquiring data: 2010 3 years running 90% CL, 3 years

52. Goals for the future Establish  13 non-zero Measure CP violation Determine mass hierarchy Also: Majorana or Dirac Sterile species?

53. e Appearance CP violation matter T2K- From Tokai To Kamioka Mass hierarchy (+/-)

54. L = 810 km NO A - New Fermilab Proposal

56. Parameters Consistent with a 1% and 4%   e oscillation probability

57. NO A (5 yr ) Daya Bay  CP normal inverted Daya Bay will complement NO A

59. FNALto Homestake

61. Neutrino Factory -- CERN layout    e + e   _ interacts giving   oscillates e     interacts giving    WRONG SIGN MUON 10 16 p/ s 1.2 10 14  s =1.2 10 21  yr 3 10 20 e  yr 3 10 20   yr 0.9 10 21  yr

62. Beta Beams

63. Other Future Studies Double beta decay (m<0.1 eV) (Majorana only!) Direct measurements (m< 1 eV) (KATRIN) Cosmological Input (m<0.2 eV) (Planck satellite)

64. My prediction: We will measure: neutrino mass hierarchy CP violation in mixing And know the role of ’s in particle physics cosmology All in time for Keh-Fei’s 70 th !!