Telescopes: SNO and the New SNOLAB Art McDonald Queen’s University, Kingston For the SNO Collaboration 2 km underground in Vale-INCO’s Creighton Mine near Sudbury, Ontario Neutrino Telescopes Venice March 10, 2009 (Galileo + 400)

Acrylic vessel (AV) 12 m diameter 1700 tonnes H 2 O inner shielding 1000 tonnes D 2 O ($300 million) 5300 tonnes H 2 O outer shielding ~9500 PMT’s Creighton mine Sudbury, CA The Sudbury Neutrino Observatory: SNO 6800 feet (~2km) underground The heavy water has been returned and development work is in progress on SNO+ with liquid scintillator and 150 Nd additive. - Entire detector Built as a Class 2000 Clean room - Low Radioactivity Detector materials

Bahcall et al., SNO SNO: Solving the “Solar Neutrino Problem” Solar Model Flux Calculations CNO SNO was designed to observe separately e and all neutrino types to determine if low e fluxes come from solar models or neutrino flavor change (New Physics) Previous Experiments Sensitive Mainly to Electron Neutrinos

Unique Signatures in SNO (D 2 O) Charged-Current (CC) e +d  e - +p+p E thresh = 1.4 MeV e only e only Elastic Scattering (ES) (D 2 O & H 2 O) x +e -  x +e - x, but enhanced for e Events point away from the sun. Neutral-Current (NC) x + d  x + n+p E thresh = 2.2 MeV Equally sensitive to e   3 ways to detect neutrons

Phase II (salt) July 01 - Sep. 03 Phase III ( 3 He) Nov. 04-Dec. 06 Phase I (D 2 O) Nov May 01 SNO: 3 neutron (NC) detection methods (systematically different) n captures on 2 H(n,  ) 3 H Effc. ~14.4% NC and CC separation by energy, radial, and directional distributions 40 proportional counters 3 He(n, p) 3 H Effc. ~ 30% capture Measure NC rate with entirely different detection system. 2 t NaCl. n captures on 35 Cl(n,  ) 36 Cl Effc. ~40% NC and CC separation by event isotropy 36 Cl 35 Cl+n 8.6 MeV 3H3H 2 H+n 6.25 MeV n + 3 He  p + 3 H p 3H3H 5 cm n 3 He

If neutrinos have mass: For 3 Active neutrinos. (MiniBoone has recently ruled out LSND result) Solar,ReactorAtmospheric As of today: Oscillation of 3 massive active neutrinos is clearly the dominant effect: For two neutrino oscillation in a vacuum: (a valid approximation in many cases) CP Violating PhaseReactor, Accel.Majorana Phases Range defined for  m 12,  m 23 Maki-Nakagawa-Sakata-Pontecorvo matrix (Double  decay only) ? ? ? Leptogenesis:  or  phases -> possible matter/antimatter asymmetry in Early Universe

Matter Effects – the MSW effect The extra term arises because solar e have an extra interaction via W exchange with electrons in the Sun or Earth. In the oscillation formula: (Mikheyev, Smirnov, Wolfenstein) MSW effect can produce an energy spectrum distortion and flavor regeneration in Earth giving a Day-night effect. If observed, matter interactions define the mass heirarchy.

The Total Flux of Active Neutrinos agrees reasonably well with solar models: 5.95 ( ) [BPS08 (GS)] 4.72 ( ) [BPS08 (AGS)] However, metal abundances, mixing …? -> CNO measurements: Haxton, Serenelli SNO Results for Salt Phase Flavor change determined by > 7  Electron Neutrinos are only 1/3 of Total -The solar results are best fit with the MSW effect and define the mass hierarchy (m 2 > m 1 ) through the Matter interaction. -SNO: CC/NC flux defines tan 2    < 1 (ie Non - Maximal mixing) by more than 5 standard deviations Solar Neutrinos (SNO plus others) Reactor Anti- Neutrinos (KAMLAND)

Final Phase: SNO Phase III Improve solar neutrino flux by breaking the CC and NC correlation: CC: Cherenkov Signal  PMT Array NC: n+ 3 He  NCD Array Improvement in  12, as Neutral-Current Detectors (NCD): An array of 3 He proportional counters:40 strings on 1-m grid: ~440 m Phase III production data taking Dec 2004 to Dec D 2 O and NCD’s now removed. NCD’s to be used in HALO: a lead-based Supernova detector for e

Neutrons from solar neutrino interactions NC Signal: 983 ± 77 Neutron background: 185 ± 25 Alphas and Instrumentals: 6126 ± 250 (0.4 to 1.4 MeV) SNO PAPER: arXiv: v3 [nucl-ex] Phys.Rev.Lett.101:111301,2008 ~ 1 alpha background event per month per meter of detector.

NCD Simulation Results data MC Energy (MeV) n Pulse Width ( n s) full model of detector physics to simulate pulse shape characteristics, correlations tuned on calibration data neutron signal alpha backgrounds: surface polonium decay bulk U and Th decay wire polonium decay wire bulk decay insulator polonium decay insulator bulk U and Th decay

statstat + syst SNO Fluxes: 3 Phases p-value for consistency of NC/CC/ES in the salt & NCD phases + D2O NC(unconstr) is 32.8%

This work: SNO NCD results agree well with previous SNO phases. Minimal correlation with CC. Different systematics. New precision on  Future solar analysis: LETA (Low Energy Threshold Analysis) 3-neutrino analysis hep flux Day-night, other variations Muons, atmospheric Solar + KamLAND fit results eV 2 degrees deg (previous) Neutrino flavour symmetry phenomenology: (Smirnov summary at Neutrino 2008) Tri-Bi-Maximal Mixing: 35.2 deg Quark-Lepton Complementarity: 32.2 deg (  12 +  Cabbibo = 45 deg) The accuracy on   and  8B will improve with new data analysis: SNO LETA

SNO Physics (Telescope) Program Solar Neutrinos (7 papers to date)  Electron Neutrino Flux  Total Neutrino Flux  Electron Neutrino Energy Spectrum Distortion  Day/Night effects  hep neutrinos hep-ex  Periodic variations: [Variations < 8% (1 dy to 10 yrs)] hep-ex/ Atmospheric Neutrinos & Muons (arXiv: hep-ex )  Downward going cosmic muon flux  Atmospheric neutrinos: wide angular dependence [Look above horizon] Supernova Watch (SNEWS) Limit for Solar Electron Antineutrinos hep-ex/ Nucleon decay (“Invisible” Modes: N ) Phys.Rev.Lett. 92 (2004) [Improves limit by 1000] Supernova Relic Electron Neutrinos hep-ex

X SNO Super-K SNO provides a test of the Super- Kamiokande oscillation parameters (  m 2 = 2.1 x ev 2, sin 2 2  = ). SNO: 2.6 x ev 2 SNO also provides a measure of the cosmic neutrino flux above the horizon. Normalization of Bartol 3-D atmospheric neutrino flux model: SNO Muon & Atmospheric Neutrino Analysis Through-going muons

SNO data for downward-going muons extends the previous data to about 13.5 km of water equivalent, where atmospheric neutrino generated muons begin to contribute significantly. Also studying neutron production From muons. New SNO paper arXiv: hep-ex Downward-going Muons

New AV Hold Down Ropes Existing AV Support Ropes The organic liquid is lighter than water so the Acrylic Vessel must be held down. New scintillator purification systems are required. SNO+ : Liquid Scintillator with Nd for Double Beta Decay + Solar, geo - Otherwise, the existing detector, electronics etc. are unchanged tonnes of liquid scintillator (LAB) (plus 1 tonne of natural Nd = 56 kg of 150 Nd for Double Beta Decay)

Nd is one of the most favorable double beta decay candidates with large phase space due to high endpoint: 3.37 MeV. Ideal scintillator (Linear Alkyl Benzene) has been identified. More light output than Kamland, Borexino, no effect on acrylic. Nd metallic-organic compound has been demonstrated to have long attenuation lengths, stable for more than 2 years. 1 tonne of Nd will cause very little degradation of light output. (Successful test in 2008 with small chamber in center of SNO) Isotopic abundance 5.6% (in SNO+ 1 tonne Nd = 56 kg 150 Nd) Possible enrichment of 150 Nd or increase in the amount of natural Nd. SNO+ Capital proposal submitted, decision June Plan to start with natural Nd in Other physics: CNO solar neutrinos, pep solar neutrinos to study neutrino properties, geo-neutrinos, supernova search. (No 11 C background at this depth.) SNO+: Neutrino-less Double Beta Decay: 150 Nd Queen’s, Alberta, Laurentian, SNOLAB, BNL, Washington, Penn, Texas, LIP Lisbon, Idaho State, Idaho Nat Lab, Oxford, Sussex, TUDresden, Leeds,UCLondon

Backgrounds assumed at Kamland observed values plus their purification objectives for 210 Bi, 40 K. Negligible background from 11 C at SNOLAB depth. Capability for 3 Years of Data pep CNO Solar Neutrinos

m  (eV) Lightest neutrino (m 1 ) in eV m  = |  i U ei ² m i | m  = |m 1 cos 2  13 cos²  12 + m 2 e 2i  cos 2  13 sin²  12 + m 3 e 2i  sin²  13 | Measuring Effective Mass normal hierarchyinverted hierarchy SNO+ Sensitivity (3 years): 0.1 eV with 1 tonne natural Nd 0.04 with 500 kg 150 Nd. Inverted Normal Present Expts eV Mass Hierarchies NormalInverted Degenerate

0 : For example: 1057 events per year with 500 kg 150 Nd-loaded liquid scintillator in SNO+. Simulation assuming light output and background similar to Kamland. (Borexino has done better) SNO+ ( 150 Nd  - less Double Beta Decay) One year of data m  = 0.15 eV Sensitivity Limits (3 yrs): 1000 kg natural Nd (56 kg isotope): m  ~ 0.1 eV (start 2011) With 500 kg enriched 150 Nd: m  ~ 0.04 eV U Chain Th Chain ~Flat 8 B Solar “background”

event rates: KamLAND: 33 events per year (1000 tons CH 2 ) / 142 events reactor SNO+: 44 events per year (1000 tons CH 2 ) / 42 events reactor Geo-Neutrino Signal SNO+ geo-neutrinos and reactor background - four times smaller reactor background in the geo-neutrino region than in KamLAND - test models in a region dominated by crustal components. - very well characterized local geology enables residuals to probe the U and Th content of the deep Earth - reactor spectrum “dip” helps constrain  m 2 and  12

Letters of Intent/Interest (Red implies approval for siting) : Dark Matter: Timing of Liquid Argon/Neon Scintillation: DEAP-1 (7 kg), MINI-CLEAN (360 kg), DEAP/CLEAN (3.6 Tonne) Freon Super-saturated Gel: PICASSO Silicon Bolometers: SUPER-CDMS (25 kg) Double Beta Decay: 150 Nd: In liquid scintillator in SNO+ 136 Xe: EXO (Gas or Liquid) (Longer Term) CdTe: COBRA (Longer Term) Solar Neutrinos: Liquid Scintillator: SNO+ (also Reactor Neutrinos, Geo-neutrinos) SuperNovae: SNO+: Liquid scintillator; HALO: Pb plus SNO 3 He detectors. SNOLAB Construction is complete – Final cleaning occurring

Neutrino 2008 Christchurch May 28 th, 2008 SNOLAB Personnel facilities SNO Cavern Ladder Labs Cube Hall Phase II Cryopit Utility Area 2009: MiniCLEAN : DEAP/CLEAN 3600 Now:DEAP : SNO+ 2009: HALO Now:PICASSO-II New large scale project. 2011: SuperCDMS ? 2010: PICASSO IIB? 2010: EXO-200-Gas? All Lab Air: Class < 2000

Personnel Facility

Lunch Room

Lunch Room Start of Clean conditions for the new SNOLAB: Feb. 2009

Cube Hall MiniCLEAN 360 kg 2009 DEAP/CLEAN 3.6 tonne 2010 Dark Matter Search with Liquid Argon: DEAP-1 (7 kg Ar) (Running); Future: Mini-Clean (360 kg Ar or Ne) and DEAP (3.6 tonnes Ar) WIMP-Induced Nuclear recoils in Ar are discriminated from beta and gamma radioactivity ( 39 Ar) by timing of the light emitted.

Dark Matter Search at SNOLAB with Liquid Argon Yellow: Prompt light region Blue: Late light region Backgrounds (  ’s) Signal (nuclear recoil) DEAP-1 at SNOLAB Background suppression better than 2.6 E-8 demonstrated to date For DEAP/CLEAN 3600 suppression of > is required. Note also that sources of Ar depleted x 20 in 39 Ar have been found and are being developed with the Princeton group.

CDMS-II: ~50 kg-days (Ge) XENON-10: ~300 kg-days (Xe) DEAP- 3600: 1,000,000 kg-days (Ar) (3 yrs) Super CDMS 25 kg

PICASSO Project In CAnada to Search for Supersymmetric Objects detectors consist of tiny (5 to 100  m) halocarbon superheated- liquid droplets (e.g. C 3 F 8, C 4 F 10 ) embedded in a gel WIMP-induced nuclear recoils nucleate a bubble; expanding, evaporating bubble produces an acoustic signal detected by piezo microphone insensitive to beta and gamma radiation; some discrimination exists for alphas 19 F favourable target to search for “spin-dependent” WIMP scattering 32 detector modules containing 4 L of gel

Phase 1a: (published in ’05 PLB, NIM) 20g 2kgd Phase Ib: (ongoing) 2.6 kg 700 kgd Bckg red. 1/6 – 1/10 Phase Ib/100: 2.6 kg 700 kgd Bckg: red. 1/100 Phase II: 25 kg 7000 kgd Larger modules 30L PICASSO PHASES MSSM Theory Predictions SPIN DEPENDENT WIMP INTERACTION: Studied with Fluorine dispersed in supersaturated gel – WIMP nuclear recoils create bubbles - detected acoustically. Low response for other radioactivity. Breakthrough this year: alpha discrimination

H elium A nd L ead O bservatory A lead detector for supernova neutrinos in SNOLAB Laurentian, TRIUMF, SNOLAB, LANL, Washington, Duke, Minnesota, Digipen IT HALO-1: 80 tons of existing Pb & SNO Neutron Detector Array Pb: Most sensitivity to electron neutrinos. ~ 50 events for SN at center of Galaxy.

SUMMARY SNO operation is complete, further papers to come over next year. SNOLAB construction is complete, final cleanliness in progress. Several experiments are already running in existing clean space. A number of other experiments have been approved for siting in the near future for neutrinos, double beta decay, Dark Matter. Stay tuned for some exciting future physics results.