2. Present Understandings

1. 2. Present Understandings Solar, Kamland MSW-LMA Atmospheric Oscillation! Decay, decoherence LSND and Sterile

2. Solar neutrinos(Non-historical)

3. Neutrino Production in the Sun Light Element Fusion Reactions p + p 2H + e+ + e 99.75 % 0.25 % p + e- + p  2H + e ~10-5 % 3He + p 4He + e+ + e 7Be + e- 7Li + e 15 % 8B  8Be* + e+ + e 0.02 %

4. Types of Experiments • Radio-Chemical • ft-value of b decay can give cross sections with a few % accuracy • n +A(Z,,N)→e + A’(Z+1,N-1) • Give rates • 37Ar(g.s.) - 37Cl = 0.816MeV • Convenient Ar life time (t = 35 days) • 71Ge(g.s.)-71Ga=0.233MeV • electron capture (t = 11.43 days)

5. Real time measurements • Water Cherenkov Super-Kamiokande • n +e → n + e well defined by standard model s (ne) ; s (nm,nt)=1:1/6 forward peaked • Heavy water Cherenkov :SNO • n + e → n + e Same as water • n + d → e + p + p (CC) measure ne component, slightly backward peaked • n + d → n + p + n (NC) same cross section for all neutrinos, thermalized neutron capture,

6. Sudbury Neutrino Observatory 2092 m to Surface (6010 m w.e.) PMT Support Structure, 17.8 m 9456 20 cm PMTs ~55% coverage within 7 m Acrylic Vessel, 12 m diameter 1000 tonnes D2O 1700 tonnes H2O, Inner Shield 5300 tonnes H2O, Outer Shield Urylon Liner and Radon Seal Energy Threshold = 5.511 MeV

7. Neutrino Reactions in SNO n +  + + n NC d p n x x Produces Cherenkov Light Cone in D2O n +  + + CC d p p e− e • Q = 1.445 MeV • good measurement of ne energy spectrum • some directional info (1 – 1/3 cosq) • ne only n captures on deuteron 2H(n, g)3H Observe 6.25 MeV g • Q = 2.22 MeV • measures total 8B n flux from the Sun • equal cross section for all n types Produces Cherenkov Light Cone in D2O +  + n e− n e− ES x x • low statistics • mainly sensitive to ne, some n and n • strong directional sensitivity

8. CC 1967.7 #EVENTS +61.9 +26.4 +49.5 +60.9 +25.6 +48.9 ES 263.6 NC 576.5 Shape Constrained Signal Extraction Results

9. Fcc(ne) = 1.76 (stat.) (syst.) x106 cm-2s-1 Fes(nx) = 2.39 (stat.) (syst.) x106 cm-2s-1 Fnc(nx) = 5.09 (stat.) (syst.) x106 cm-2s-1 +0.06 +0.09 +0.24 +0.46 +0.12 +0.44 -0.43 -0.12 -0.09 -0.23 -0.43 -0.05 Shape Constrained Neutrino Fluxes E> 5.511 MeV Signal Extraction in FCC, FNC, FESwith Signal Extraction in Fe, Fmt

10. FSNO = 5.09 +1.01 FSSM= 5.05 106cm-2 s-1 106cm-2 s-1 - 0.81 +0.44 +0.46 -0.43 -0.43 SNO NC in D2O (April 2002) ~ 2/3 of initial solar ne are observed at SNO to be nm,t Flavor change at 5.3 s level. Sum of all the fluxes agrees with SSM. Phys. Rev. Lett. 89 (2002)

11. What have been clarified • NC measurement confirmed main sequence star calculation SNO-NC = 5.09 +0.44-0.43+0.46-0.43 SSM calc. =5.05 +1.01-081 • . • electron neutrino component for >5MeV reduced to ~35% of SSM

12. The Solar Neutrino deficiencies Experiment Exp/SSM • SAGE+GALLEX/GNO 0.55 • Homestake 0.34 • Kamiokande+SuperK 0.47 • SNO CC 0.35 We need survival probabilities of 8B: ~1/3 7Be: <1/3 pp: ~2/3 Hard to accommodate by vacuum oscillation

13. Definition of mixing angle and components • Define n1, n2 such that m2 > m1 Dm2 >0 • Small angle solution n1~ne, n2 ~ nx • Large angle solution • q>45o cos2q <0 equivalently negative Dm2 Ares (>0) =Dm2 cos2q is not realized • Matter effect determine sign of (m22-m12)

14. MSW in the Solar neutrinos In(Dm2) ne m2 n2 m1 In(sin2q) Matter in earth may regenerate ne more events in the night!

15. Matter-Enhanced Neutrino Oscillations Pee Spectrum • Neutrinos produced in weak state e • High density of electrons in the Sun • Superposition of mass states 1, 2, 3 changes through the MSW resonance effect • Solar neutrino flux detected on Earth consists of e + m,t Day/night Spectrum

16. Super-Kamiokande • Known 8B- b decay spectrum predict spectrum of neutrinos • Spectrum distortion • Day-Night comparison

17. (0.75, 6.310-11eV2) Justso (6.310-3, 510-6eV2) SMA (0.8, 3.210-5eV2) LMA Bad fit for SMA and Just-so(vacuum oscillation) solutions.

18. Energy distribution for day/night-6bins Z Day SK MAN1 MAN2 MAN3 core MAN4 mantle MAN5 CORE SK 1258 days 22.5 kt SSM = BP2000 + new B8 spec. (Preliminary)

19. SK Constraint on mixing parameters using SSM 8B  flux prediction zenith spectrum shape alone Excluded Regions Allowed Regions Phys. Lett. B (2002) 179

20. SSM 68%CL SNO NC 68%CL SNO CC 68%CL SNO ES 68%CL SK ES 68%CL vertex 391-day salt phase flux measurements cosqsun ~ isotropy CC NC

21. global solar data with 391-day SNO salt

22. Kamland

23. KamLAND detector 1000m Cosmic ray 's are suppressed by 1/100,000. 20 inch : 225 13m 1,000 ton liquid scintillator Dodecane : 80% Pseudocumene : 20% PPO : 1.5g/l Mineral oil Dodecane : 50% Isoparaffin : 50% 1.75m thickness 17 inch :1325 20 inch : 554 ~8000 photons / MeV λ: ~10m Photo - coverage: 34% ~ 500 p.e. / MeV

24. + p e+ + n e ν detection in KamLAND e (0.51) Prompt e+ signal e- e Te++annihilation =Eν- 0.8MeV e+ Te+ p (0.51) E1.8MeV n  (2.2 MeV) Delayed γ by neutron capture p ~210μs • Position • Time correlation • delayed energy information d Greatly removes backgrounds

25. Reactors near the KamLAND 80% of total contribution comes from 130~220km distance effective distance ~180km Reactor neutrino flux, ~95.5% from Japan ~3% from Korea (2nd result period)

26. Energy Spectrum • Hypothesis test of scaled no-oscillation: χ2/ndf = 37.3/18 ⇒ spectral distortion at > 99.6% C.L. • Rate + Shape: no oscillation is excluded at 99.999995% C.L.

27. L/E plot with data for geo-ν analysis (759 days, 5m fiducial) low energy window best fit reactor + geo-neutrino model prediction Oscillation pattern with real reactor distribution Lo = 180 km is used for KamLAND There is clear Oscillatory behavior (peak and dip) oscillation parameter is determined.

28. q12 -Solar(ne) and Reactor(ne) Neutrino - hep-ex/0406035

29. 8 • Two mass eigen-states haveDm2~8x10-5 eV2 • Lighter mass state contain ne more than 50%

30. →e+nm+ne nm+nm ne+ne Atmospheric Neutrinos Mixture of ne, ne, nm & nm Primary cosmic rays nm+nm flux nm (protons, He, , ,) 3D calculation L=10~20 km p, K m 10-1 1 10 102 En(GeV) nm e p→m+nm Flux ratio Low EnergyLimit nm : ne = 2 : 1 ne nm 2 10-1 1 10 102 En(GeV)

31. Event topology ne + N  e + X nm + N  m + X nt + N t + X FC PC Initial neutrino energy spectrum Stopping muons Through-going muons FC + PC stopping muons Interaction in the rock through-going muons

32. A half of nm lost!

33. q q ~6000 km Earth Survival Probability p=1 GeV/c, sin2 2q=1 Dm2=310–3(eV/c2)2 Half of the up-going ones get lost

34. nm CC nt CC En(GeV) Cross Section of nt interacts very weakly with matter (nucleons) due to threshold effect of charged lepton mass Disappearance of neutrinos if nm→nt in atmospheric n

35. SK-I Zenith angledistributions (w/ 100yr MC) SK-I Atmospheric n Full Paper hep-ex/0501064 1R e up-m 1R m MR m <400MeV <400MeV sub-G stopping 1R m MR m up-m 1R e Number of events >400MeV >400MeV multi-G through cosQ 1R e 1R m data PC CR MC F? s? multi-GeV multi-GeV w/ oscillation fit cosQ cosQ cosQ up down

36. Guide line Data/prediction L/E (km/GeV) L/E analysis and Parameter determination All the data 1489.2days Data/prediction 100 1000 L/E (km/GeV) Rejected events horizontally going events:  due to large dL/dcosq low energy events:  due to large qnm angle 2726 events (3726 ev. expected) ~ 1 /5 of total data

37. Resolution Cuts vs Dc2 Dc2 50 60 70 80 90 (%) Result of L/E analysis (SK-I) 1489.2 days FC+PC • The first dip has been observed at ~500km/GeV • This provide a strong confirmation of neutrino oscillation • The first dip observed cannot be explained by other hypotheses Decoherence Decay Oscillation 3.4 sto decay 3.8 sto decoherence

38. Constraint on the neutrino oscillation parameters from L/E analysis Best Fit (Physical Region) Dm2=2.4x10-3,sin22q=1.00 c2min=37.8/40 d.o.f. (sin22q=1.02, c2min=37.7/40 d.o.f) 1.5x10-3 < Dm2 < 3.4x10-3 eV2 0.92 < sin22q (@90%C.L.) Dm2 Allowed region (@90%C.L.) 1.9x10-3 < Dm2< 3.0x10-3 eV2 0.90 < sin22q Consistent with the standard zenith angle analysis

39. nm →Sterile ?

40. matter effect in the earth for sterile neutrinos PC, Evis>5GeV <Eν>～25GeV up/down ratio ns ns Z νμーνs νμーνs n νμーντ νμーντ n up through going μ <Eν>～100GeV vertical/horizontal ratio Compare high-low energy events

41. ne nm nt Three Flavor Mixing in Lepton Sector mass eigenstates Weak eigenstates m1 m2 m3 cij = cosqij, sij=sinqij Atm. Sol. q12, q23, q13 + d (+2 Majorana phase) Dm122, Dm232, Dm132

42. q13

43. CHOOZ 425 GWth L=1km 5t Liquid Scintillator H richparaffin Gd loaded (g 8MeV) sin22q13 <0.10 9° 90%CL sin22q13 <0.17 12°

44. Two mass eigen-states haveDm2~8x10-5 eV2 • Define n1, n2 such that • mn2 > mn1 • Solarn MSW in neutrino (not anti-neutrino) • n1 is the largest component inne • Third mass eigen-sate (n3) isseparated byDm2~ ±3x10-3 eV2 • Smallne component inn3 (n3 consists ofnm, nt, almost 50;50)which is larger in nt ? (q23<p/4 ?) • neutrino mass and charged lepton mass ordering • same or inverted 8 atm. 3x10-3eV2

45. LSND/KARMEN Experiment

46. The LSND Experiment View of the PMTs inside the detector vessel. (Vessel is filled with scintillator oil.)

47. Small intrinsic ne contamination few x10-4 Decay at Rest (DAR) • Signal • Prompt e+ • Delayed g from n-capture

48. Gamma Ray Distribution

49. LSND Final Results

50. ISIS and KARMEN