1 / 44

Solar Neutrino Results

Solar Neutrino Results. Tadao Mitsui Research Center for Neutrino Science, Tohoku University. July 26, 2004 6th International Workshop on Neutrino Factories & Superbeams. Osaka University, Osaka, Japan. Solar and reactor neutrinos. Results from Super-Kamiokande and SNO

Download Presentation

Solar Neutrino Results

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Solar Neutrino Results Tadao Mitsui Research Center for Neutrino Science, Tohoku University July 26, 20046th International Workshop on Neutrino Factories & Superbeams Osaka University, Osaka, Japan

  2. Solar and reactor neutrinos • Results from Super-Kamiokande and SNO • Reactor results from KamLAND • Radiochemical results and earlier works • Near future prospects (*2) (*1) (*1) neutrinograph of the sun by Super-K, (*2) hep-ph/0406294

  3. Chlorine (1964 ~ 1994) • First solar neutrino observation • Established solar neutrino deficit • 615-ton C2Cl4, ne(37Cl, 37Ar)e- • Final result: 2.56 ± 0.16 ± 0.16 SNU • SSM (BP04) expectation: 8.5  1.8 SNU • Data/SSM = 0.30 ± 0.03 Still important input in the current global analysis for solar neutrino 0.813 MeV 8B, 7Be SSM BP04: J.N. Bahcall and M.H. Pinsonneault PRL 92, 121301 SNU: 1 n interaction / sec each 1036 target atoms

  4. Kamiokande (1987 ~ 1995) • First measurement of time, direction, energy of solar-n • Data/SSM=0.55 ± 0.04 ± 0.07 • Upgraded to Super-K 7 MeV 8B PRD 44 (1991) 2241

  5. Gallium experiments • Sensitive to pp neutrino (main component of solar-n) • ne(71Ga, 71Ge)e- • 68.1 ± 3.75 SNU (GALLEX + GNO + SAGE) • SSM (BP04): 131+12-10 SNU • Data / SSM = 0.52 ± 0.03 new results (*1) 0.233 MeV pp, 7Be, 8B (*1) C.M. Cattadori, Neutrino 2004

  6. Four solutions that were allowedonly with fluxes (Cl, Ga, Kamiokande) (LMA) Mikheyev-Smirnov- Wolfenstein (MSW) ~106 range in Dm2

  7. Super-Kamiokande (1996 ~ ) • 50 kton water cherenkov • 22.5 kton fiducial • ~ 15 events / day (> 5 MeV) ( 8B, (hep) ) n + e-n + e- well remembers n energy, direction

  8. Super-Kamiokande-I (1496 days) May 31, 1996 - July 13, 2001 M. Nakahata, Neutrino 2004, PLB 539, 179

  9. Super-Kamiokande-I (1496 days) May 31, 1996 - July 13, 2001 M. Nakahata, Neutrino2004, PLB 539, 179

  10. SK-I: energy and zenith angle 2-D spectrum“zenith spectrum” Allowed (with SSM 8B flux) Excluded without 8B flux (rate) PLB 539, 179

  11. SMA, Just-so: excluded by energy spectrum

  12. LOW, LMA: constrained by day/night Expected “regeneration” of ne during night: too large compared with the data

  13. Only LMA at 98% C.L. May 2002 • Asdf Ga + Cl + SK + SNO rates + SK zenith spectrum PLB 539, 179

  14. Sudbury Neutrino Observatory (SNO) 1999 ~ 1000 ton D2O 12-m diameter acrylic vessel 1700 ton H2O Support structure for 9500 8-inch PMTs 5300 ton outer H2O

  15. Unique sensitivity to neutrino flavor CC: charged current ne + d  p + p + e- • fCC = fe • fNC = fe +fm + ft = f(all active n) • fES = fe + 0.154  (fm + ft) • Determine fe, fm/t + 1 redundancy energy, (direction) NC: neutral current ne + d  p + n + n nm n + d 3He + 6.25-MeV g (phase I) nt ES: elastic scattering (also SK) ne + e-ne + e- energy, direction nm nt

  16. Results: extraction of 3 reactions PRL 89, 011301, results from 306.4 days cos qsun - 60.9 CC: 1967.7+61.9 events NC: 576.5+49.5 events ES: 263.6+26.4 events - 48.9 - 25.6 Vertex Energy

  17. Deduced nm/t “appearance” Evidence for flavor transformation Significance for non-zero fm/t SK-ES + SNO-CC: 3.3s PRL 87(2001), 071301 SK-ES + SNO-CC,NC,ES: 5.5s • PRL 89(2002), 011301 With SNO-phse-II (salt) data fBP04 = 5.79 (±23%) SSM “verified” M. Nakahata, NOON2004

  18. Only LMA at 99.5% C.L. July 2002 from day/night spectral shape analysis PRL 89, 011302 SNO day/night spectra + all solar +1.3 - 1.2 -ADN = 7.0 %  4.9% %

  19. KamLAND A. Suzuki, Neutrino 98 • Reactor ne experiment • To reach solar-n solution • 100 improvement on Dm2 sensitivity 100 1 100 Chooz Palo Verde LMA

  20. Powerful commercial reactors

  21. First results from KamLAND Dec. 2002 PRL 90, 021802 ne disappearance: 99.95 % C.L.

  22. Impact of KamLAND http://hitoshi.berkeley.edu/neutrino/ assuming CPT invariance

  23. LMA-I and LMA-II from spectral shape analysis LMA-II: Dm2~1510-5 eV2 LMA-I: Dm2~710-5 eV2 PRL 90, 021802 95 % C.L.

  24. LMA: precise studySK-I reanalysis: un-binned (time, energy) PRD 69, 011104 (R) Sept. 2003 Dm2=6.310-5 eV2, tan2q=0.55 • To use all information of zenith angle dependence during night • Un-binned maximum likelihood method for time and energy

  25. Consistent results Un-binned (PLD 69, 011104) Binned (PLB 539, 179)

  26. Day/night: statistical error 25% reduced Binned (PLB 539, 179) Un-binned (PLD 69, 011104) +1.3 - 1.2 +1.3 - 1.2 ADN = - 1.8 %  1.6% % ADN = - 2.1 %  2.0% % (at best fit LMA) LMA-II disfavored observed (± 1s) LMA-I LMA-II expected

  27. After SK un-binned analysisLMA-II is excluded at >95 % C.L. Sept. 2003 All solar All solar + KamLAND 1st result 95% C.L. allowed M. Nakahata, Neutrino 2004 PRD 69, 011104 (R)

  28. SNO enhanced neutral current (salt) phase Sept. 2003 PRL 92, 181301 NC: neutral current Phase-I (Nov. 99 - May 01) Total eff. 39.9% ne + d  p + n + n nm 14.4% (phase-I) n + d 3He + 6.25-MeV g nt 2 ton NaCl dissolved Phase-II (July 01 - Sep 03) g(6 MeV) ne + d  p + n + n n nm n + 35Cl 36Cl + 8.6-MeV g’s nt Single cherenkov ring Isotropic event

  29. Energy spectra: not assumed but measured cos qsun Isotropy Vertex Energy Not used to extract reactions

  30. CC / NC = fe / factive without assuming 8B spectral shape CC/NC No oscillation 1.0 SNO salt result Maximal mixing 0.5 Maximal mixing excluded at 5.4s 1.0

  31. After SNO-salt,LMA-II is excluded at >99% 3s LMA-II PRL 92, 181301

  32. SNO CC/NC disfavors LMA-II, and also maximal-mixing LMA-II SNO salt result (CC/NC=0.306) Maximal mixing hep-ph/0309299 P.C. Holanda & A.Yu. Smirnov

  33. KamLAND: 2nd reactor results with 4.7 data hep-ex/0406035 A. Kozlov (Working Group 1)

  34. Verification of standard solar model J.N. Bahcall, M.C. Gonzalez-Garcia, C. Pena-Garay, hep-ph/0406294 All flux free parameter 90, 95, 99%, 3s 90, 95, 99%, 3s

  35. Verification of standard solar model J.N. Bahcall, M.C. Gonzalez-Garcia, C. Pena-Garay, hep-ph/0406294 All flux BP04 Oscillation: robust against solar model 95, 99%, 3s 90, 95, 99%, 3s KamLAND global analysis

  36. Solar neutrino measurement flux at production hep-ph/0406294 f  “measured” / SSM(BP04) • Without KamLAND, and GNO new results: fpp = 1.02 ± 0.02 (1s) fB = 0.88 ± 0.04 fBe = 0.91 + 0.25 / - 0.62 • With KamLAND, and GNO new results: fpp = 1.01 ± 0.02 fB = 0.87 ± 0.04 fBe = 1.03 + 0.24 / - 1.03 Small difference despite KamLAND new result Solar-n: robust against neutrino oscillation

  37. Near future: SNO 3He phase J.F. Wilkerson, Neutrino 2004 • 3He proportional counter: to detect n from NC • Event-by-event separation • Better CC energy spectrum

  38. Near future: SNO 3He phase J.F. Wilkerson, Neutrino 2004 • All 40 3He strings installed (April, 2004) • Will run for 2.5 years  2 precision of present SNO result

  39. Near future: full reconstruction of SK • 11,146 PMTs with protection cases • Full reconstruction from 2005 (plan) • SK-III from ~2006 Acrylic + FRP cases

  40. Near future: full reconstruction of SK M. Nakahata, Neutrino 2004

  41. Near future: Borexino C. Galbiati, Neutrino 2004 Toward 7Be solar-n observation

  42. Near future: KamLAND-II • 210Pb: ~105 reduction needed • R&D almost finished: achieved ~104 reduction with test bench • SiO2 adsorption: achieved 95% reduction • Complex purification system Toward 7Be solar-n observation

  43. Summary • Solar neutrino oscillation: MSW-LMA is the solution • Dm2 = 8.2 +0.6-0.510-5 eV2 tan2q = 0.40 +0.09-0.07 (a global analysis by KamLAND) • Standard solar model verified with 5% accuracy (8B) • Further precise study in the near future (SNO 3He, SK-III, Borexino, KamLAND-II etc)  solar astrophysics, search for new phenomena

More Related