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Takaaki Kajita ICRR, Univ. of Tokyo

Nufact05, Frascati, June 2005. Review of results using non-terrestrial sources - update of solar and atmospheric neutrino results -. Takaaki Kajita ICRR, Univ. of Tokyo. outline. ◆New solar neutrino data from SNO and neutrino oscillations

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Takaaki Kajita ICRR, Univ. of Tokyo

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  1. Nufact05, Frascati,June 2005 Review of results using non-terrestrial sources - update of solar and atmospheric neutrino results - Takaaki Kajita ICRR, Univ. of Tokyo

  2. outline ◆New solar neutrino data from SNO and neutrino oscillations ◆New atmospheric neutrino data from Super-K and neutrino oscillations

  3. New Results from SNO salt phase SNO collab nucl-ex/0502021 Also, M.Chen ENTApP2005

  4. History of SNO 1999 2000 2001 2002 2003 2004 2005 2006 NOW Pure D2O (1) Salt ? (3) 3He Counters (2) (4) (1) ne++de-+p+p (CC) (also compared with SK n+en+e) (3) nx+dnx+p+n, n+35Cl36Cl+g’s(S8.6MeV) (NC) & ne+de-+p+p (CC) (2) nxdnxpn, n+dt+g(6.25MeV) (NC) &ne+de-+p+p (CC) (4) New! Same as (3), but with improved stat. and syst.

  5. +0.06 −0.06 +0.08 −0.09 +0.22 −0.22 +0.15 −0.15 +0.21 −0.21 +0.38 −0.34 fCC(ne) = 1.68 (stat.) (syst.) × 106 cm−2s−1 fES(nx) = 2.35 (stat.) (syst.) × 106 cm−2s−1 fNC(nx) = 4.94 (stat.) (syst.) × 106 cm−2s−1 391-day salt phase flux measurements vertex cosqsun ~ isotropy w/o 8B energy constraint ※The previous number based on 254days salt data was: 0.306±0.026±0.024.

  6. ne and (nm+nt) fluxes SSM 68%CL SNO NC 68%CL SNO CC 68%CL SNO ES 68%CL SK ES 68%CL All the data are consistently explained within the standard oscillation

  7. Pure D2O Salt phase CC spectrum constrained Salt phase Un-constrained Comparison of results from SNO-D2O phase and SNO-salt phase CC NC

  8. ANC(%) ACC(%) New day-night results from the salt-phase A = 2(fN-fD) / (fN+fD) ANC=0 not required, E spectrum unconstrained: ACC= -0.056±0.074±0.053 LMA prediction = +2.7% ANC=0 required, E spectrum constrained: ACC= -0.015±0.058±0.027 Combined result with the pure D2O ACC(=0.070±0.049+0.013-0.012): ACC(phase-I+II)=+0.037±0.040 Combined result with the Super-K AES (=0.021±0.020+0.012-0.013) assuming the dilution factor due to nm and nt fluxes is 1.55: ACC(SNO+SK)=+0.035±0.027  consistent with the LMA prediction

  9. SNO collab nucl-ex/0502021 Also many other analyses Oscillation Analysis with 391-day Salt global solar plus latest KamLAND and new SNO salt global solar with new SNO salt Best fit q12=33.9deg. (previous = 32.5deg)

  10. Signal 5482 +132-130 (stat.) 7.0 – 20.0 MeV 622 days SK-II Preliminary SK collab. Y.Takeuchi WIN05 New SK-II data SK-II Flux = 2.36 ±0.06 (stat.)+0.16-0.15x 106/cm2/sec (SK-I flux: 2.35  0.02(stat.)  0.08(sys.) ) Preliminary (Day-Night) +0.024 - 0.025 ADN= = 0.014+/-0.049(stat.) (sys.) (Day+Night)/2 (SK-I D-N asymmetry: -0.021+/-0.020+0.013-0.012) Ready to start the physics analysis with the SK-II data.

  11. SK collab. K.Scholberg, WIN05 New atmospheric neutrino results • SK-I atmospheric neutrino analysis with finer binning. • Solar term effect and sin2q23 (SK-I) • Detection of CC nt interactions (SK-I) • SK-II data and 2 flavor oscillation analysis • SK-II L/E analysis (preliminary)

  12. Full oscillation 1/2 osci. SK-I natm analysis with finer binning In the previous atmospheric neutrino analyses in Super-K, Zenith-angle analysis  good for sin22q L/E analysis  good for Dm2 Single analysis that gives best sin22q and Dm2 ? Important energy range to see the oscillation dip = multi-GeV Finer energy bins for multi-GeV events 180  370 bins in (p, zenith, ev-type)

  13. Expected sensitivities (MC 5yr exposure) @(sin22q, Dm2)truth = (1.00, 2.5×10-3) Zenith-180bin Zenith-370bin L/E Zenith-370bin

  14. Kam Soudan-2 K2K MACRO Allowed region from the finer binning analysis Old zenith-angle analysis L/E analysis (preliminary) 90% CL allowed region: sin22q > 0.93 2.0 < Dm2 < 3.0×10-3eV2 Also consistent with all the other data

  15. Solar term effect to atmospheric n Peres & Smirnov NPB 680 (2004) 479 Because of the LMA solution, atmospheric neutrinos should also oscillate by (q12, Dm122). s22q12=0.825 Dm212=8.3×10-5 Dm223=2.5×10-3 sin2q13=0 However, due to the cancellation between nmne and nenm, the change in the ne flux is small. s2q23=0.4 =0.6 =0.5 Oscillation probability is different between s2q23=0.4 and 0.6 discrimination between q23 >p/4 and <p/4 might be possible by studying low energy atmospheric ne and nm events.

  16. Constraint on sin2q23 with and without the solar terms (preliminary) w/o solar terms w/ solar terms Still (almost) maximum mixing is most favored. hep-ph/0408170 found the c2 minimum at sin2q23=0.46 (Also E.Lisi this conference) …We need to understand the reason for this difference.

  17. Search forCCntevents CC ntMC CC nt events nt hadrons t nt hadrons ● Many hadrons ．．．． (But no big difference with other (NC) events．) BADt- likelihood analysis ● Upward going only GOOD Zenith angle Only ～ 1.0 CC ntFC events/kton・yr (BG (other n events) ～ 130 ev./kton・yr)

  18. Tau likelihood (or NN) analysis • total visible energy • number of ring candidates • distance between n interaction point and decay-e point • max(Pm) • clustered sphericity • log(sphericity) • Selection Criteria • multi-GeV, multi-ring • most energetic ring : e-like • log(likelihood) > 0 orNN > 0.5 downward upward Cut Cut DATA BG-MC tau-MC DATA BG-MC tau-MC Number of events (×1.82t MC) t-likelihood t-likelihood

  19. Zenith angle dist. and fit results (prelim., new) Likelihood analysis NN analysis Data ×1.93 t-MC ×1.82 t-MC Data Number of events nm, ne, & NC background nm, ne, & NC background cosqzenith cosqzenith Fitted # of t events Expected # of t events

  20. SK-II atmospheric neutrino data FC&PC: 627days, Up-going muons: 609days e-like m-like

  21. Allowed osc. parameter region (preliminary) New ! (preliminary) SK-II data are consistent with the SK-I data. (SK-I + II combined analysis: next stage)

  22. SK-II L/E analysis L/E analysis was carried out for the SK-II data with the identical selection criteria as those in SK-I. SK-II SK-I (preliminary) Decoh. Decay Osc. Consistent with SK-I. Oscillation still gives the best fit to the data.

  23. Allowed parameter region based on the SK-II L/E analysis SK-II SK-I (preliminary) New ! SK-II data are consistent with the SK-I data. (SK-I + II combined analysis: next stage)

  24. Summary • New SNO salt result • New SK(-II) atmospheric neutrino results • No surprise • But our knowledge on neutrino masses and mixing angles are improving.

  25. end

  26. Oscillation Analysis Input: • latest SAGE, final Gallex/GNO, final Cl • SK 1496-day zenith-spectrum • SNO-I (pure D2O) summed spectra day+night (CC+ES+NC+backgrounds) • SNO-II (391-day salt) extracted CC spectra (day+night), NC and ES fluxes (day+night) • KamLAND 766 ton-yr results

  27. Binning for new analysis (=same binning as 3 flavor analysis) Same as old analysis finer binning Sample used in 3-flavor Sub-GeV Multi-GeV Up-stop Single-Ring m Multi-Ring m PC- stop Single-Ring e Multi-Ring e PC- through Up-through En CC ne CC nm 37 momentum bins x 10 zenith bins = 370 bins in total Fewer number of events per bin Poisson statistics to calculate c2

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