Results from the SNO Salt Phase

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2 Results from the SNO Salt Phase Kevin Graham Queen s s University NOON 4 Tokyo

3 A Long Time Ago neutrinos are massless e 511 kev ν e < 3 ev µ 16 MeV ν µ <.19 MeV τ 1.78 GeV ν τ <18. MeV

4 Well Not Really! What do we want to know and how? Verify flavour change Definitive Oscillation Signal Measure mass splittings/hierarchy Mixing angles How many types? Sterile? Majorana? Measure individual mass eigenstates CP violation? Magnetic moment? Long Baseline Short Baseline Off-axis Atmospheric Solar Reactor Double Beta Decay Supernova Solar measuring θ 1, m 1

5 ij ij ij ij i i i τ τ τ µ µ µ e e e li s and where c e e c s s c iδ e c s s c c s s c U U U U U U U U U U θ θ δ α α sin, cos / / = = = = + i li l U ν ν = If neutrinos have mass: ) E L m. ( θ ) ν P(ν e µ 17 sin = sin For three neutrinos: Solar,Reactor Atmospheric Using the oscillation framework: For two neutrino oscillation in a vacuum: (valid approximation in many cases) CP Violating Phase Reactor... Majorana Phases Range defined for m 1, m 3 Maki-Nakagawa-Sakata-Pontecorvo matrix (Double β decay only)???

6 SNO Physics Program Solar Neutrinos Electron Neutrino Flux Total Neutrino Flux Electron Neutrino Energy Spectrum Day/Night effects Seasonal variations hep neutrinos Atmospheric Neutrinos & Muons Downward going cosmic muon flux Upward going muons and angular dependence Supernova Watch Antineutrinos Nucleon decay ( Invisible( Invisible Modes: N ννν) Focus for Today

7 Solar Neutrinos Φ = cm - sec -1 Experimental Results SAGE+GALLEX/GNO Flux =.58 SSM Homestake Flux =.33 SSM Kamiokande+Superkamiokande Flux =.46 SSM SNO (CC.35) Flux = 1 SSM

8 The SNO Detector 39 m to surface 9438 Inward- Looking PMTs 1 m diameter Acrylic vessel 91 Outward Looking PMTs (Veto) PMT Support Structure (PSUP) 53 tonnes light water 1 tonnes heavy water 17 tonnes light water Norite Rock

9 Neutrino Reactions in SNO CC ν e + d p + p + e - Q = MeV - good measurement of ν e energy spectrum - some directional info (1 1/3 cosθ) - ν e only NC ν + d p + n + x ν x - Q =. MeV - measures total 8 B ν flux from the Sun - equal cross section for all ν types + e ES ν e νx + x - low statistics - mainly sensitive to ν e, some ν µ and ν τ - strong directional sensitivity

10 Phase I (pure DO): 36.4 live days T e > 5 MeV R < 55 cm 98 events SNO Data Taking Phases Phase II (salty D O): 54. (~4) days T e > 5.5 MeV R < 55 cm 355 events Phase III ( 3 He n counters): Counters in! n capture on 3 He n + 3 He p + t n capture on D Single 6.5 MeV γ n capture on Cl Multiple γ s 8.6 MeV Channels indep. no correlation High CC-NC corr. T e constrained High CC-NC corr. T e unconstrained Reduced NC systematics Past Present Future

11 Signal Extraction Results Pure D O Phase #EVENTS 36.4 Live Days CC ES NC Events per 5 kev (c) CC 1 NC + bkgd Bkgd neutrons ES (MeV) T eff Events per.1 wide bin (b) Fiducial Volume Bkgd 1 CC NC + bkgd neutrons ES (R/R AV ) Events per.5 wide bin 16 (a) CC ES NC + bkgd neutrons Bkgd cos θ sun

12 Flux Results Pure D O Phase Φ Φ e µτ = 1.76 = ( stat.) ( stat.) ( syst.) 1 ( syst.) cm cm s s σ effect Neutrinos Massive s -1 ) 6 cm - (1 φ µτ SNO φ ES SNO φ CC SNO φ NC SSM φ NC (1 φ e - cm -1 s ) Constrained Fit for flavour change test Φ Φ SSM SNO = 5.5 = (.44.46) (.43.43) Without Constraint Φ + ( ) SNO = 6. 4 ( )

13 Solar Neutrino Flux Day/Night Asymmetries A x = (Φ NIGHT Φ DAY ) (Φ NIGHT +Φ DAY ) Separate Spectra For Day and Night Signal Extraction in Φ CC, Φ NC, Φ ES Signal Extraction in Φ e, Φ total +A total = A SNO CC A SNO NC = 14. ± 6.3 = -.4 ± A SNO e = 7. ± 4.9 A SK e = 5.3 ± SNO data consistent with MSW oscillation interpretation

14 What We Measure PMT Measurements -position -charge -time 14 1 x PMT charge Reconstructed Event -event vertex -event direction -energy -isotropy

15 Detector Calibration Optics Energy Event Reconstruction Neutron Capture Backgrounds { Tools Pulsed Laser 337nm to 6 nm 16 N 6.13 MeV γ s 3 } H(p,γ) 4 He 19.8 MeV γ s 8 Li <13. MeV β s 5 Cf neutrons U/Th 14 Bi & 8 Tl β γ s Monte Carlo

16 Optical Measurements from Laserball Optical Constants laser at 6 wavelengths scan through detector DO Attenuation HO+AV attenuation PMT Angular Response Rayleigh Scattering Salt phase Calibration used for MC simulation Energy calibration Check systematics Pure D O phase

17 Energy Calibration Timing Cut Prompt Time ns time window reduce noise/model uncertainties Energy Calibration Detector State Corrections Optical Correction to Centre Data MC 16 N to set scale 16 N at centre of detector refelections σ=1.46 ns Data MC

18 Energy Calibration generate MC electrons energies from -3 MeV create look-up table Nhits Energy resolution function Nhit/MeV Table Resolution Function σ E =A + B(T E ).5 + C T E

19 Energy Systematics Sources Include: Detector State Stability 16 N Runs Optical Model Radial/Asymmetry Timing MC model Total Uncertainty ~1% Resolution Scale

20 Neutrons in Salt NaCl Capture Higher capture cross section Higher energy release Many gammas n 36 Cl * 35 Cl 36 Cl γ σ =.5 b H+n 6. MeV σ = 44 b 35 Cl+n 8.6 MeV 3 H 36 Cl

21 Neutron Capture Efficiency in SNO 35 Cl(n,γ) 36 Cl Average Eff. =.399 T e 5.5 MeV and R γ 55 cm H(n,γ) 3 H Average Eff. =.144 T e 5. MeV and R γ 55 cm Total Systematic Uncertainty ~3%

22 Cerenkov Light and β 14 Legendre Polynomials Use: β 14 = β 1 + 4β 4 Systematic Uncertainty ~1% Charged particle, v > c/n Use for Signal Extraction! 1 cone θ ij θ ik >1 cone

23 D O Radioactivity Assays Controlled radon spike Radon assay collection points Top of AV /3 up Bottom of AV Radium Assay techniques MnOx HTiO <1 n/day bkg

24 Signal Extraction Unconstrained Variables: E, R 3, cosθ sun, β 14 NC E higher Less Rad. Sep. 8 B Shape Constrained Energy R 3 Signal Bkg Extended ML Fit CC NC ES } Φ e Φ µτ Fit Cerenkov Photodis. Fix Perturb Shift Variables PDF s Fluxes Systematic Uncertainties cosθ sun Directionality Unchanged β 14 θ ij Isotropy Separation!

25 Measured distributions Measure External n background Kinetic Energy Position Isotropy Direction

26 Comparison with phase I 355 candidate events 54 live days Φ SSM = B shape constrained #EVENTS CC ES NC Pure D O (phase I) Salt (phase II) Φ Φ Φ Φ Φ Φ I cons. CC I cons. ES I cons. NC II cons. CC II cons. ES II cons. NC = 1.76 = = 5.9 = 1.7 ±.7( stat.) = ( stat.) ( stat.) ( stat.) ( stat.) = 4.9 ±.4( stat.) ( syst.) ( syst.) ( syst.) ( syst.) ( syst.) ( syst.) Φ Φ Φ Φ 8 B shape unconstrained I unc. NC II unc. CC II unc. ES II unc. NC = 1.59 = = ( stat.) ( stat.) ( syst.) ( syst.) ( stat.) ±.1( syst.) = 5.1±.7( stat.) ±.38( syst.)

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28 -ν oscillation region defined by SNO

29 Global analysis of solar and reactor neutrino data --9% --95% --99% % LMA I allowed only at 99.73% c.l. Maximal mixing rejected at 5.4 σ m = θ = deg ev

30 Summary Pure D O Phase: Flavour Transformation Neutrinos Massive SSM working well Global Results: MSW Model LMA Favoured Salt: Increased NC statistics Additional Isotropy Separation Precision Fluxes with No Shape Constraint Improved CC/NC Measurement Full Salt Data Set (another ~15 days) Day/Night - Spectral Shape Eccentricity Improved precision in MSW space Global Results: Lower LMA Region Not Maximal Mixing Next Phase: NCDs going in ( 3 He counters) event-by-event separation Improved systematics No CC-NC correlation

31 The SNO Collaboration T. Kutter, C.W. Nally, S.M. Oser, C.E. Waltham University of British Columbia J. Boger, R.L. Hahn, R. Lange, M. Yeh Brookhaven National Laboratory A.Bellerive, X. Dai, F. Dalnoki-Veress, R.S. Dosanjh, D.R. Grant, C.K. Hargrove, R.J. Hemingway, I. Levine, C. Mifflin, E. Rollin, O. Simard, D. Sinclair, N. Starinsky, G. Tesic, D. Waller Carleton University P. Jagam, H. Labranche, J. Law, I.T. Lawson, B.G. Nickel, R.W. Ollerhead, J.J. Simpson University of Guelph J. Farine, F. Fleurot, E.D. Hallman, S. Luoma, M.H. Schwendener, R. Tafirout, C.J. Virtue Laurentian University Y.D. Chan, X. Chen, K.M. Heeger, K.T. Lesko, A.D. Marino, E.B. Norman, C.E. Okada, A.W.P. Poon, S.S.E. Rosendahl, R.G. Stokstad Lawrence Berkeley National Laboratory M.G. Boulay, T.J. Bowles, S.J. Brice, M.R. Dragowsky, S.R. Elliott, M.M. Fowler, A.S. Hamer, J. Heise, A. Hime, G.G. Miller, R.G. Van de Water, J.B. Wilhelmy, J.M. Wouters Los Alamos National Laboratory S.D. Biller, M.G. Bowler, B.T. Cleveland, G. Doucas, J.A. Dunmore, H. Fergani, K. Frame, N.A. Jelley, S. Majerus, G. McGregor, S.J.M. Peeters, C.J. Sims, M. Thorman, H. Wan Chan Tseung, N. West, J.R. Wilson, K. Zuber Oxford University E.W. Beier, M. Dunford, W.J. Heintzelman, C.C.M. Kyba, N. McCauley, V.L. Rusu, R. Van Berg University of Pennsylvania S.N. Ahmed, M. Chen, F.A. Duncan, E.D. Earle, B.G. Fulsom, H.C. Evans, G.T. Ewan, K. Graham, A.L. Hallin, W.B. Handler, P.J. Harvey, M.S. Kos, A.V. Krumins, J.R. Leslie, R. MacLellan, H.B. Mak, J. Maneira, A.B. McDonald, B.A. Moffat, A.J. Noble, C.V. Ouellet, B.C. Robertson, P. Skensved, M. Thomas, Y.Takeuchi Queen s University D.L. Wark Rutherford Laboratory and University of Sussex R.L. Helmer TRIUMF A.E. Anthony, J.C. Hall, J.R. Klein University of Texas at Austin T.V. Bullard, G.A. Cox, P.J. Doe, C.A. Duba, J.A. Formaggio, N. Gagnon, R. Hazama, M.A. Howe, S. McGee, K.K.S. Miknaitis, N.S. Oblath, J.L. Orrell, R.G.H. Robertson, M.W.E. Smith, L.C. Stonehill, B.L. Wall, J.F. Wilkerson University of Washington

32 A Few Additional Slides

33 SNO Phase III (NCD Phase)- Begins 4 3 He Proportional Counters ( NC Detectors ) 4 Strings on 1-m grid 44 m total active length Detection Principle H + ν x p + n + ν x -. MeV (NC) ν x PMT 3 He + n p + 3 H +.76 MeV Physics Motivation Event-by-event separation. Measure NC and CC in separate data streams. Different systematic uncertainties than neutron capture on NaCl. NCD array removes neutrons from CC, calibrates remainder. CC spectral shape. NCD n

34 Why Event-by by-event? Phase I Phase III Projected Source CC/CC (%) NC/NC (%) NC/NC (%) Energy Scale -4., , Energy Resolution -.9, +. -., Energy Non-linearity ±.1 ±.4. Vertex Resolution ±. ±.1. Vertex Accuracy -.8, +.9 ±1.8. Angular Resolution -., , +.3. Internal Source p-d ±. -1.5, External Source p-d ±.1-1., DO Cherenkov -.1, , +1.. HO Cherenkov ±. -., +.4. AV Cherenkov ±. -., +.. PMT Cherenkov ±.1 -.1, Neutron Capture ±. -4., Σ Systematic -5., , Σ Statistical -.8, , Σ Uncertainties CC NC anti-correlation

35 Matter Effects the MSW effect m = 4E i d dt ν e ν x cosθ + m 4E = sinθ H G ν e ν x F e H N m sinθ 4E m cosθ 4E The extra term arises because ν e have an extra interaction via W exchange with electrons in the Sun or Earth. In the oscillation formula: sin θ m ω = = ( ω G sin θ cosθ ) + sin F N e E / m θ

36 For the unconstrained fits Correlation coefficients: Ratio:

37 Measuring U/Th Content Ex-situ Ion exchange ( 4 Ra, 6 Ra) Membrane Degassing ( Rn) Events per bin (arbitrary units) count daughter product decays In-situ Low energy data analysis Separate 8 Tl & 14 Bi (c) Using Event isotropy Bi decays Tl decays Mean angle between PMT hits - θ ij Concentration (g Th/g D O) Concentration (g U/g D O) ' a) 3 Th 1 Neutron Events In-situ MnOx HTiO b) 38 U In-situ Rn Assay Goal: < 3.7x1-15 g Th/g D O Goal: < 4.5x1-14 g U/g D O 3 D O 4 Days Since Prod. Running Weighted Average H O/AV

38 Energy & Misreconstruction

39 Backgrounds

40 Uncertainties in Fluxes (%) (unconstrained fit) Energy scale Resolution Radial accuracy Angular res. Isotropy mean Isotropy width Radial E bias Internal neutrons Cher. bkds AV events Neutron capture Total CC uncert. NC uncert. ES uncert.

41 Holanda, Smirnov Hep-ph 17 Salt Only FUTURE SNO CC/NC Contours Improved Precision Day Night Contours (%) Improved Precision Also improved Precision for Spectral distortion