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Solar Neutrinos, SNO, and SNOLAB

Solar Neutrinos, SNO, and SNOLAB. Ongoing physics motivation for solar neutrino measurements Status of SNO, SNOLAB Future solar neutrino experiments, SNO+. Art McDonald For the SNO, SNO+ Collaborations SNOW 2006, Stockholm, Sweden. If neutrinos have mass:.

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Solar Neutrinos, SNO, and SNOLAB

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  1. Solar Neutrinos, SNO, and SNOLAB • Ongoing physics motivation for solar neutrino measurements • Status of SNO, SNOLAB • Future solar neutrino experiments, SNO+ Art McDonald For the SNO, SNO+ Collaborations SNOW 2006, Stockholm, Sweden

  2. If neutrinos have mass: Using the oscillation framework for neutrino flavor change: For three neutrinos: Maki-Nakagawa-Sakata-Pontecorvo (MNSP) matrix (Double b decay only) Solar,Reactor Atmos., Accel. CP Violating Phase Reactor, Accel Majorana Phases Range defined for Dm12, Dm23 For two neutrino oscillation in a vacuum: (valid approximation in many cases)

  3. Matter Effects – the MSW effect (Mikheyev, Smirnov, Wolfenstein) The extra term arises becausene have an extra interaction via W exchange with electrons in the Sun or Earth. In the oscillation formula: MSW effect can produce an energy spectrum distortion and flavor regeneration in Earth giving a Day-night effect

  4. , SNO Bahcall et al. (2001) SAGE GNO Chlorine SK,SNO pep 7Be pp Oscillations for Solar Neutrinos Solar Model Flux Calculations Matter Interaction Effect:LMA CNO Current Data for ne Survival 2005 was a sad year for solar neutrino physics with the passing of Hans Bethe and John Bahcall

  5. Vacuum pp 8B LMA Bahcall & Pena-Garay hep-ph/0305159 Future solar neutrino measurementspp, 7Be, pep, 8B • NEUTRINO PHYSICS • - Confirm matter effects (MSW). • - Improve Q12, Q13. • - Search for effects of sterile n, • Non-Standard Interactions, • Mass-varying neutrinos. • SOLAR PHYSICS • - Accurate measurement of • neutrino luminosity (pp, pep). • - Observe CNO neutrinos. pep 7Be • Compare ES, CC • Compare ES, SSM

  6. Unique Signatures in SNO (D2O) Charged-Current (CC) e+d  e-+p+p Ethresh = 1.4 MeV eonly Neutral-Current (NC) x+d x+n+p Ethresh = 2.2 MeV Equally sensitive to e nmt 3 ways to detect neutrons Elastic Scattering (ES) x+e- x+e- x, but enhanced fore

  7. Solar Neutrino Physics From SNO Fx Fx FCC+ (FES - FCC) x (1/0.15) Fnc = = Clear Evidence: Flavor change + active neutrino appearance FCC ne June 2001 (with SK) 3.3 s = FES ne + 0.15 (nm+ nt) ne FCC 5.3 s April 2002 = FNC ne +nm+ nt Sept. 2003 March 2005 > 7 s With salt in SNO Total 8B Solar Neutrino Flux June 2001 April 2002 ~10% Sept. 2003 March 2005

  8. 35Cl+n 2H+n 8.6 MeV 6.25 MeV 3H 36Cl 3 neutron (NC) detectionmethods (systematically different) Phase I (D2O) Nov. 99 - May 01 Phase II (salt) July 01 - Sep. 03 Phase III (3He) Nov. 04-Dec. 06 n captures on 2H(n, g)3H Effc. ~14.4% NC and CC separation by energy, radial, and directional distributions 2 t NaCl. n captures on 35Cl(n, g)36Cl Effc. ~40% NC and CC separation by event isotropy 40 proportional counters 3He(n, p)3H Effc. ~ 30% capture Measure NC rate with entirely different detection system. 5 cm n 3H p 3He n + 3He  p + 3H

  9. New Information: Charged Current Energy Spectrum Data from Experiments in Operation The latest SNO data: 391 live days with salt hep-ex/0502021 March 2005 Day-Night Asymmetry assuming ANC=0

  10. Flavor change determined by > 7 s. CC, NC FLUXES MEASURED INDEPENDENTLY nm , nt The Total Flux of Active Neutrinos is measured independently (NC) and agrees well with solar model Calculations: 5.82 +- 1.3 (Bahcall et al), 5.31 +- 0.6 (Turck-Chieze et al) Electron neutrinos Improved accuracy for q12.

  11. - The solar results define the mass hierarchy (m2 > m1) through the Matter interaction (MSW) - SNO: CC/NC flux defines tan2q < 1 (ie Non - Maximal mixing) by more than 5 standard deviations SOLAR ONLY AFTER NEW SNO SALT DATA Large mixing Angle (LMA) Region only LMA for solar n predicts very small spectral distortion, small (~ 3 %) day-night asymmetry, as observed by SNO, SK SOLAR PLUS KAMLAND (assuming CPT) (Reactor n’s)

  12. Oscillation Parameters, 2-D joint 1-s boundary Marginalized 1-D 1-s errors Results from SNO -- Salt Phase SNO D2O D/N spectra SNO Salt D/N spectra KamLAND 766-day SK-I zenith spectra SAGE Gallex/GNO Cl/Ar

  13. hep-ex/0507079 Periodicity in Solar Flux? SNO data 1999-2003 Unbinned Maximum Likelihood Method compares fit for Sinusoidal variation with Expectation for zero amplitude. Monte Carlo used to estimate sensitivity shows 35% probability of a larger likelihood ratio (S) with zero sinusoidal amplitude than the maximum S observed in the fits. Conclusion: No observed sinusoidal variation at periods from 1 day to 10 years. Analysis sensitive to amplitude of 8-10% at 99% C.L..

  14.  = 0.014(9). Actual: 0.0167 Orbital Eccentricity  = 0.021(3) SNO: hep-ex/0507079 SK: hep-ex/0508053

  15. Summary of SNO results • Direct observation (7 s) of neutrino flavor changevia an appearance measurement: Beyond the Standard Model for Elementary Particles. • Direct measurement (10 % accuracy) of total flux of active neutrinos:Strong confirmation ofSolar Models. • The dominant transformation is to active neutrinos: Sterile neutrino fraction is restricted (<~ 13%). • Clear determination (5.3 s): q12 is non-maximal. • With other solar measurements: Strong evidence for Matter Enhancement in Sun (MSW – LMA solution). • With Kamland and CPT:Strong confirmation of neutrino oscillation due to finite mass (MNSP) as the primary physics explanation for appearance and disappearance measurements.

  16. Present Phase: SNO Phase III Neutral-Current Detectors (NCD): An array of 3He proportional counters 40 strings on 1-m grid ~440 m total active length • Search for spectral distortion • Improve solar neutrino flux by breaking the CC and NC correlation ( = -0.53 in Phase II): • CC: Cherenkov Signal PMT Array • NC: n+3He  NCD Array • Improvement in 12, as Blind Analysis Phase III production data taking began Dec 2004; completion at the end of 2006

  17. Neutral Current Detector Array deployed by a remotely operated submarine. Production data and calibrations steadily since Nov. 2004

  18. SNO Energy Calibrations: 25% of running time 6.13 MeV 19.8 MeV Energy calibrated to ~1.5 % Throughout detector volume 252Cf neutrons + AmBe, 24Na b’s from 8Li g’s from 16N and t(p,g)4He Optical calibration at 5 wavelengths with the “Laserball”

  19. The objective is for an improved CC/NC ratio measurement compared to the salt phase

  20. SNO Physics Program • Solar Neutrinos (5 papers to date) • Electron Neutrino Flux • Total Neutrino Flux • Electron Neutrino Energy Spectrum Distortion • Day/Night effects • hep neutrinos (paper in progress) • Periodic variations hep-ex/0507079 [Variations < 8% (1 dy to 10 yrs)] • Atmospheric Neutrinos & Muons • Downward going cosmic muon flux • Atmospheric neutrinos: wide angular dependence [Look above horizon] • Supernova Watch (SNEWS) • Limit for Solar Electron Antineutrinos hep-ex/0407029 • Nucleon decay (“Invisible” Modes: N nnn) Phys.Rev.Lett. 92 (2004) [Improve limits by 1000] • Supernova Relic Electron Neutrinos

  21. New International Underground Science Facility At the Sudbury site: SNOLAB - Underground Laboratory (2 km deep) ($ 38M): Complete mid- 2007 - Surface Laboratory ($ 10 M): Complete September, 2005 • To pursue: • Future observations from a possible SNO+ detector • Solar Neutrinos • Geo - neutrinos • Supernova Neutrinos • Reactor Neutrinos • Dark Matter (WIMPS) • Measurements of nuclear recoils with ultra-low background • Double Beta Decay: • Are Neutrinos Majorana particles? • More accuracy for neutrino masses

  22. The New SNOLAB New Excavation To Date SNO

  23. Cosmic Ray Muons Vs Depth

  24. Letters of Interest for SNOLAB Solar Neutrinos: Liquid Ne: CLEAN (also Dark Matter) Liquid Scintillator: SNO+ (also Double Beta Decay, Reactor Neutrinos, Geoneutrinos, Supernovae) Liquid Helium (also Dark Matter) Dark Matter: Silicon Bolometers: CDMS Liquid Xe: ZEPLIN, XENON Gaseous Xe: DRIFT Freon Super-saturated Gel: PICASSO Timing of Liquid Argon Scintillation: DEAP Neutrinoless Double Beta Decay: Ge Crystals: Individual cryostats (MAJORANA) or Large Liquid Nitrogen bath Liquid Xe: EXO CdTe: COBRA Recent Workshop and Experiment Review Committee Aug 14-16, 2005

  25. Future low-energy solar  experiments * * SNOLAB Dan McKinsey Talk + SNOLAB * funded [Nakahata@NOON04]

  26. SNO+ • After heavy water is removed from SNO in 2007: • SNO plus liquid scintillator → physics program • pep and CNO low energy solar neutrinos (11C: 20 x < Gran Sasso) • SSM pep flux: uncertainty ±1.5%  allows precision test. • Comparison with the photon luminosity. • Tests the neutrino-matter interaction, sensitive to new physics. • non-standard interactions, mass-varying neutrinos, CPT violation,large 13, sterile neutrino admixture…. • geo-neutrinos • 240 km baseline reactor oscillation confirmation • supernova neutrinos • double beta decay (150Nd) ?

  27. Survival Probability Rise stat + syst + SSM errors estimated SSM pep flux: uncertainty ±1.5% known source → precision test Dm2 = 8.0 × 10−5 eV2 tan2q = 0.45 improves precision on q12 SNO CC/NC • sensitive to new physics: • non-standard interactions • solar density perturbations • mass-varying neutrinos • CPT violation • large q13 • sterile neutrino admixture Studying the rise confirms MSW or perhaps shows us new physics pepn

  28. New Physics NC non-standard Lagrangian Friedland, Lunardini, Peña-Garay, hep-ph/0402266 • non-standard interactions • MSW is linear in GF and limits from n-scattering experiments  g2aren’t that restrictive • mass-varying neutrinos Miranda, Tórtola, Valle, hep-ph/0406280 Sterile Neutrinos: de Holanda and Smirnov hep-ph/0307266 pep solar neutrinos are at the “sweet spot” to test for new physics Barger, Huber, Marfatia, hep-ph/0502196

  29. Event Rates (Oscillated) resolution with 450 photoelectrons/MeV 7Be solar neutrinos 3600 pep/year/kton >0.8 MeV using BS05(OP) and best-fit LMA 2300 CNO/year/kton >0.8 MeV

  30. 11C Cosmogenic Background these plots from the KamLAND proposal muon rate in KamLAND: 26,000 d−1 compared with SNO: 70 d−1

  31. KamLAND (7Be  phase) impurities present goal reduction distillation purge 238U 232Th 40K 85Kr 210Pb (3.5 ± 0.5) x 10-18 g/g (5.2 ± 0.8) x 10-17 g/g < 2.7 x 10-16 g/g ~ 1 Bq/m3 ~ 10-20 g/g 10-16 g/g 10-16 g/g 10-18 g/g ~1 mBq/m3 ~10-25 g/g OK OK 10-2 10-6 10-5 < 10-2 < 10-5 < 10-4 < 10-5 • Elastic scattering: • nx+ e-→nx+ e- • R&D work focus on reducing radioactive backgrounds in the liquid scintillator. pep Kamland Purification System to be installed in 2006

  32. Default Scintillator Identified Like Ivory SNOW Soap: (99 + 44/100) % Pure. It Floats! • Linear Alkyl Benzene (LAB) has the smallest scattering of all scintillating solvents investigated • LAB has the best acrylic compatibility of all solvents investigated • density r = 0.86 g/cm3:Hold down acrylic vessel. • …default is Petresa LAB with 4 g/L PPO, wavelength shifter 10-50 mg/L bisMSB • because solvent is undiluted and SNO photocathode coverage is high,expect light output (photoelectrons/MeV) ~3× KamLAND

  33. Geo-Neutrino Signal • terrestrial antineutrino event rates: • Borexino: 10 events per year (280 tons of C9H12) / 29 events reactor • KamLAND: 29 events per year (1000 tons CH2) / 480 events reactor • SNO+: 64 events per year (1000 tons CH2) / 87 events reactor based on Rothschild, Chen, Calaprice Geophys. Res. Lett. 25, 1083 (1998) KamLAND geo-n in SNO+ SNO+ geo-neutrinos and reactor background KamLAND geo-neutrino detection…July 28, 2005 in Nature

  34. SNO++ (Nd Double Beta Decay) 0n: 1057 events per year with 1% natural Nd-loaded liquid scintillator in SNO++. Simulation assuming light output similar to Kamland. Very preliminary simulation: one year of data mn = 0.15 eV

  35. SNO+ Collaboration Queen’s M. Chen*, M. Boulay, X. Dai, K. Graham, A. Hallin, C. Hearns, C. Kraus, C. Lan, J.R. Leslie, A. McDonald, V. Novikov, P. Skensved, A. Wright, U. Bissbort, S. Quirk Laurentian D. Hallman, C. Virtue SNOLAB B. Cleveland, R. Ford, I. Lawson Brookhaven National Lab A. Garnov, D. Hahn, M. Yeh Los Alamos National Lab A. Hime LIP Lisbon J. Maneira • potential collaborators from outside SNO (Italy, Germany, Russia) have indicated some interest new collaborators welcome A subset of the SNO collaboration will continue with SNO+ * Principal Investigator We are working on a SNO+ proposal to be submitted this fall.

  36. Some other fun SNOLAB experiments as time permits

  37. Letters of Interest for SNOLAB Solar Neutrinos: Liquid Ne: CLEAN (also Dark Matter) Liquid Scintillator: SNO+ (also Double Beta Decay, Reactor Neutrinos, Geoneutrinos, Supernovae) Liquid Helium (also Dark Matter) Dark Matter: Silicon Bolometers: CDMS Liquid Xe: ZEPLIN, XENON Gaseous Xe: DRIFT Freon Super-saturated Gel: PICASSO Timing of Liquid Argon Scintillation: DEAP Neutrinoless Double Beta Decay: Ge Crystals: Individual cryostats (MAJORANA) or Large Liquid Nitrogen bath Liquid Xe: EXO CdTe: COBRA Recent Workshop and Experiment Review Committee Aug 14-16, 2005

  38. http://arxiv.org/astro-ph/0411358 scintillation pulse-shape analysis for discrimination of e- vs nuclear recoils -> no electron-drift DEAP : Dark-matter Experiment with Argon PSD

  39. Background rejection with LAr (simulation) [Mark Boulay] From simulation, rejection > 108 @ 10 keV (>>!) 108 simulated e-’s 100 simulated WIMPs

  40. Discrimination in liquid argon from DEAP-0 <pe> = 60 O(1in 105) consistent with room background (preliminary) preliminary <pe> = 60 corresponds to 10 keV with 75% coverage • Final analysis and systematics evaluation being done

  41. DEAP-0 DEAP- 1 (2 kg) Is under Construction at Queen’s. To be Sited in SNOLAB In 2006

  42. Spin Independent Interaction } Where we Are Minimal Super- Symmetric Models } Some Future Expts. Liquid Ar scintillation M.G. Boulay & A. Hime, astro-ph/0411358

  43. Fluorine is very sensitive for the spin-dependent interaction Montreal, Queen’s Indiana, Pisa, BTI

  44. SPIN - DEPENDENT INTERACTION 20 g: hep-ex/0502028 1 kg 2 kg to be run in 2006 10 kg 100 kg

  45. Conclusions • The Sudbury Neutrino Observatory (SNO) has provided fundamental measurements of neutrino and solar properties. • Neutrino measurements have opened new areas of investigation for physics beyond the Standard Model of Elementary Particles. • With SNO, SNO+ and the deepest international underground site (SNOLAB) we have an exciting future for sensitive measurements of solar neutrinos, double beta decay and dark matter particles.

  46. Another Canada – Sweden connection: Hockey Mats Sundin

  47. Congratulations to Sweden Olympic Hockey Champions!

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