Super-Kamiokande ~The Status of n Oscillation ~

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1 May 26, 2006 Vulcano Workshop 2006 Super-Kamiokande ~The Status of n Oscillation ~ Yoshihisa OBAYASHI (ICRR, Univ. of Tokyo) for Super-Kamiokande Collaboration May 26, 2006 Vulcano

2 News: SK is Fully Reconstructed! Apr All PMTs are mounted with acrylic/frp covers and start water filling May 14: Celebration for SK 10 th anniversary and Commissioning of SK-III PMT with cover Many T2K collaborators took reconstruction shifts Now: Half of tank is filled with water End of Jun. 2006: Filled with water and restart observation May 26, 2006 Vulcano

3 42 m Super-Kamiokande 50kton pure water (22.5kt fid.vol.) (Inner detector) (Outer detector) PMTs 1000m underground 2700m wat. eq m May 26, 2006 Vulcano

4 4 History Start SK-I SK-II SK-III # of PMT (Photo Coverage) 11,146 (40%) Accident Partial Reconstruction Full Reconstruction 5,182 (19%) 11,129 (40%) Energy Threshold (Solar n) 5 MeV 7 MeV 4 MeV(plan) Major Physics Outputs Atm. n Oscilaltion Phys. Rev. Lett. 81,1562(1998) Solar n Oscilaltion Phys. Rev. Lett. 86,5651(2001) Atm. n L/E Phys. Rev. Lett. 93, (2004) K2K Final Result

5 Overview Atmospheric Neutrinos nm disappearance analysis nm nt or other modes? Solar Neutrinos SK-I results SK-II update Improvement for SK-III Supernovae Neutrinos Summary May 26, 2006 Vulcano

6 6 Atmospheric Neutrinos p, He Zenith angle Q Downward (L=10~100 km) Event Classification p ±, K ± m ± Fully Contained (FC) (E n ~1GeV) n m e ± Partially Contained (PC) (E n ~10GeV) n m n e Upward (L=up to km) Stopping m (E n ~10GeV) Through-going m (E n ~100GeV) Particle ID (Fully Contained) e- like mu- like

7 7 Zenith Angle Distribution SK-I : 1489 days SK-II : 804 days n m n t oscillation (best fit) null oscillation FC FC < < FC FC FC > FC > FC FC

8 8 Oscillation Analysis m/e double ratio allowed region (n m n t ) Update from Phys. Rev. D 72, (2005) (SK-I results) Sub-GeV SK-II : SK-I : ( m / e) ( m / e) DATA MC Best Fit: Dm 2 = 2.5 x 10-3 ev 2 sin 2 2q = 1.00 c 2 = / 755 dof (18%) Multi-GeV (FC+PC) ( m / e) DATA SK-II : ( m / e) MC SK-I : x 10-3 ev 2 < Dm 2 < 3.1 x 10-3 ev 2 sin 2 2q > 0.93 at 90% CL

9 L/E analysis Update from Phys. Rev. Lett. 93,101801(2004) Select good L/E resolution (<70%) events Perform oscillation analysis with L/E binning May 26, 2006 Vulcano

10 10 L/E Analysis result Zenith angle binning Oscillation Decay Decoherence c 2 osc c 2 dcy c 2 dec = 83.9/d.o.f = 107.1/d.o.f, Dc 2 = 23.2(4.8σ) = 112.5/d.o.f, Dc 2 = 27.6(5.3σ)

11 11 3 Flavor Oscillation Submitted to Phys. Rev. D, see hep-ex/ In the case q 13 0: ne excess may be seen Matter effect enhance n e appearance vacuum matter nm ne oscillation probability, Dm 2 =2.5x10-3 ev 2, sin 2 q 23 =0.5, sin 2 q 13 =0.04

12 3 Flavor Analysis Result Excess of up-going ne? SK-I data shows no excess yet Allowed region Consistent with pure nm nt SK-I 1489days Best fit (Dm 2 =2.5 x10-3 ev 2, sin 2 q 23 =0.5, sin 2 q 13 =0.0) Expected excess (Dm 2 =2.5x10-3 ev 2, sin 2 q 23 =0.5, sin 2 q 13 =0.04) May 26, 2006 Vulcano

13 Tau Appearance Search Tau Enrich Sample: Evis>1.33GeV (Multi-GeV) Most energetic ring is e-like Likelihood selection Visible Energy Sphericity Distance between n interaction and decay-e Zenith angle fit with tau signal and nm background May 26, 2006 Vulcano

14 14 n m n t or n sterile? Admixture model: Consistent of 0% of n s, Arrow ~25% of sterile at 90% CL

15 15 Other than Oscillation? LIV S.Coleman & S.L. Glashow PRD 59(116008),1999 V.Barger et. al., PRL 85(24), Dm P OSC sin 2q sin Db L E Best fit: c2(377dof)=399, (a=0.053,sin2q v =0.093) a<~10-24 Best fit: c2(377dof)=399, (a=0.06,sin2q v =0.0) a<~10-24 Db<~10-23

16 16 Solar Neutrinos 8 B neutrino electron scattering n + e - n + e - SSM Expectation Typical Solar n event 5.94(1+/-0.01)x10 10 /cm 2 /s (BP04 SSM) 5.79(1+/-0.23)x10 6 /cm 2 /s 8 B Ee = 9.1MeV cosqsun = 0.95

17 Solar n Data of SK-I May 31, 1996 July 13, 2001 (1496 days ) n + e - n + e solar n events (14.5 events/day) 8 B flux : [x 10 6 /cm 2 /sec] Data SSM(BP2004) = May 26, 2006 Vulcano

18 18 n e and n m +n t Fluxes(SK and SNO Results) SK SNO ES = [x10 6 /cm 2 /s] CC = ES = e m,t CC = e SNO NC = NC = e + m + t (cf. SSM(BS2005) = 5.69±0.93) Obtained total flux: exp = 5.2±0.3 SK SNO CC SNO NC ± (BS2005)

19 19 Energy spectrum of SK-I (tan 2 q, Dm 2 ) Energy correlated systematic error

20 20 Solar n results from SK-I Region represents allowed values of neutrino properties

21 21 SK-II Solar n data (Preliminary)

22 Energy Spectrum May 26, 2006 Vulcano

23 23

24 24

25 P(n e n e ) E May 26, 2006 n (MeV) Vulcano Solar SK-III n e survival probability Recoil electron spectrum To see ~10% spectrum distortion, Lower energy threshold Minimize statistic error Minimize systematic error sys. error sin 2 (q) Dm 2 (ev 2 ) 6.3 x x x x x 10-5

26 26 Background from SK-I Y.Takeuchi et al., PLB452(1999)418

27 Improvement May 26, 2006 Vulcano

28 28 Supernova Neutrino Bursts No candidate was found in SK-I and SK-II 2.3 T < 0.39 SN/yr (90%CL) Upper limit of galactic SN rate < Efficiency vs. Distance T: measurement time

29 29 Supernovae Relic Neutrinos Reactor n Solar 8 B Solar hep Expectations Population synthesis (Totani et al., 1996) Constant SN rate (Totani et al., 1996) Cosmic gas infall (Malaney, 1997) Cosmic chemical evolution (Hartmann et al., 1997) Heavy metal abundance (Kaplinghat et al., 2000) LMA n oscillation (Ando et al., 2002) Atmospheric n Phys. Rev. Lett. 90, (2003) SK-I Total background Atmospheric n m invisible m decay e 90% CL limit of SRN Atmospheric n e

30 Atmospheric Neutrinos Summary Oscillation analysis result based on SK-1 (1489d) +SK- 2(890d) is presented Further analysis based on SK-I(1489d) Consistent with nm nt oscillation. Some non-tau modes: unlikely Solar Neutrinos Oscillation analysis based on SK-I(1469d) is presented SK-II data also analyzed though energy threshold is 7MeV Improvements for SK-III is going on Upper limits for SN and SRN rate obtained May 26, 2006 Vulcano

31 Supplements May 26, 2006 Vulcano

32 Tau Appearance Search May 26, 2006 Vulcano

33 33 Zenith Angle Distributions (SK-I bins) n m n t oscillation (best fit) null oscillation

34 34 Zenith Angle Distributions (SK-II bins) n m n t oscillation (best fit) null oscillation

35 SK-I + SK-II combined analysis (data binning) P lep Sub-GeV Multi-GeV FC 1ring e-like CC n e FC mring e-like CC n m FC 1ring m-like FC mring m-like PC stop PC thru UP stop UP through showering UP through non-showering 38 event type and momentum bins x 10 zenith bins 380 bins Since various detector related systematic errors are different, we do not combine the SK-I and SK-II bins. 380 bins for SK-I bins for SK-II 760 bins in total

36 SK-I + SK-II combined analysis (systematic errors) neutrino flux (14) neutrino interaction (12) Identical for SK-I and SK-II solar activity (1) event selection and reconstruction (21) Regarded as independent between SK-I and SK-II The total number of systematic errors is : Flux (14) + Interaction (12) + SK-I (22) + SK-II (22) = 70

37 Result from SK-I + SK-II data SK-I : 1489 days SK-II : 804 days Best Fit: Dm 2 = 2.5 x 10-3 ev 2 sin 2 2q = 1.00 c 2 = / 755 dof (18%) 1.9 x 10-3 ev 2 < Dm 2 < 3.1 x 10-3 ev 2 sin 2 2q > 0.93 at 90% CL

38 SK+ K2K Combined Results K2K K2K Combine Combine SK SK Combined result sin 2 2q Dm 2 [ev 2 ] Best fit point Best in phys Arrowed region of Dm sin 2 2q (-9%) ~ 2.84(+13%) [ev 2 ] (68%) 2.17(-14%) ~ 3.03(+21%) [ev 2 ] (90%) May 26, 2006 Vulcano