Status of the Sudbury Neutrino Status of the Sudbury Neutrino Observatory (SNO)Observatory (SNO)

Alan Poon for the SNO Collaboration

Institute for Nuclear and Particle AstrophysicsLawrence Berkeley National Laboratory, Berkeley, USA

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Outline

• What we did…(Phase I: Pure D2O target)

• What we are doing…(Phase II: D2O + NaCl)

• What we will be doing…(Phase III: Neutral Current Detectors)

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Sudbury Neutrino Observatory

1700 tonnes of inner shielding H2O

12.01m dia. acrylic vessel

17.8m dia. PMT Support Structure9456 20-cm dia. PMTs56% coverage

5300 tonnes of outer shielding H2O

Urylon liner

1006 tonnes D2O

Nucl. Inst. Meth. A449, 127 (2000)

2 km

to

su

rfac

e

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Detecting at SNO

NCxx

npd

ES -- ee x x

CC-epd e p

• Low Statistics • (e) 6 () 6 ()

• Strong directionality:

• Measurement of e energy spectrum

• Weak directionality:

• Measure total 8B flux from the sun• e

1−0.340cosθ

€

θe ≤ 18o (Te = 10 MeV)

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Phase I: Extracting the Solar Flux

• PDFs: kinetic energy T, event location R3, and solar angle correlation cos θsun

SignalsRadioactive

Backgrounds

Amplitudes Free Amplitudes Fixed

PerturbObservables:

€

r R ,

r u ,T

Shift amplitudes(±1 σ)

Max. Likelihood Fit

€

φCC φ NC φ ES

€

φe φμτ

OR +

CC NC ES

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

See : Phys.Rev.Lett. 89 (2002) 011301 Phys.Rev.Lett. 89 (2002) 011302

Solar Model predictions are verified: [in 106 cm-2 s-1]

Phase I: Missing Solar ’s Found

€

φe =1.76 +0.05

−0.05(stat.) +0.09

−0.09(syst.) ×106 cm−2s−1

φμτ = 3.41+0.45

−0.45(stat.) +0.48

−0.45(syst.) ×106 cm−2s−1

8B shape constrained fit:

No 8B shape constraint:

€

φCC (ν e ) = φe

φNC (ν x ) = φe + φμτ

φES (ν x ) = φe + 0.15φμτ

Null hypothesis of no flavor transformation rejected at 5.3

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φSSM (BP01) = 5.05 +1.01

−0.81

€

φSNOconstrained = 5.09 +0.44

−0.43(stat.)

+0.46

−0.43(syst.)

φSNOunconstrained = 6.42 +1.57

−1.57(stat.)

+0.55

−0.58(syst.)

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Correlation in Signal Extraction (Phase I)

CC ES NC

CC 1.000 -0.162 -0.520

ES -0.162 1.000 -0.105

NC -0.520 -0.105 1.000

Correlation Matrix

Strong statistical anti-correlation between NC and CC in the signal extraction

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φSNOconstrained = 5.09 +0.44

−0.43(stat.)

+0.46

−0.43(syst.)

φSNOunconstrained = 6.42 +1.57

−1.57(stat.)

+0.55

−0.58(syst.)

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Phase II (D2O + 2 tons NaCl)

Variables CC Stat. Error

NC Stat. Error

ES Stat. Error

* E,R,θsun 3.4 % 8.6% 10%

* R, θsun 9.5% 24% 11%

E,R,θsun 4.2% 6.3% 10%

E,R,θsun, Iso. 3.3% 4.6% 10%

R,θsun,Iso. 3.8% 5.3% 10%

* PRL, 89, No. 1, 011301, (2002)

Sim

ulation

• Added 2 tons of salt in June 2001 to enhance NC detection efficiency and to improve the separability of NC and CC Cherenkov signals

• CC: Single electron (Cherenkov signal less isotropic)

• NC: Multiple ’s following n capture on 35Cl(Cherenkov signal more isotropic)

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Phase II: Blind Analysis

• ~ 280 live days• Triple blind analysis to ensure independence from Phase I

– CC, ES: • data set pre-scaled by an “unknown” factor of 80±10%

– NC:• Leak an “unknown” number of spallation neutrons in the data • NC interaction cross section in the Monte Carlo is spoiled by an “unknown” factor

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Phase II: Analysis & Challenges

I. Energy Scale Drift

Absolute Energy Scale Uncertainty~1.1% (preliminary) [c.f. 1.2% in Phase I]

II. Light Isotropy

Mott scattering missing in EGS4, now added in the SNO Monte Carlo

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Phase II: Analysis & Challenges

III. Neutron Efficiency IV. 24Na

• 23Na (in the plumbing) activated by neutrons from the rock wall

• 24Na decays and emits 2 (1.37, 2.75 MeV)

• calibrated by controlled activation

√(x2+y2) [cm] √(x2+y2) [cm]

Z [c

m]

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Decoupling CC and NC in Phase III

• CC: Cherenkov Signal PMT Array

• NC: n+3He Neutral Current Detector Array

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

SNO Summary

• Final full detector calibration of Phase II completed• Analysis of the blind data is complete…box to be opened

upon completion of internal review• Other analyses in progress: solar anti-neutrino, day-night

flux, proton decay, atmospheric neutrinos, muon spallation…Stay tuned!

Phase II (D2O+NaCl)

Phase III (Neutral Current Detector)

• All 3He counters have been constructed and stored in the underground lab• All counters are being characterized• Integration of electronics and DAQ in progress• Deployment in Fall 2003

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

The SNO Collaboration

G.Milton, B.SurAtomic Energy of Canada Ltd., Chalk River Laboratories

S.Gil, J.Heise, R.J.Komar, T.Kutter, C.W.Nally, H.S.Ng, Y.I.Tserkovnyak, C.E.WalthamUniversity of British Columbia

J.Boger, R.L Hahn, J.K.Rowley, M.YehBrookhaven National Laboratory

R.C.Allen, G.Bühler, H.H.Chen*

University of California, Irvine I.Blevis, F.Dalnoki-Veress, D.R.Grant, C.K.Hargrove, I.Levine, K.McFarlane, C.Mifflin, V.M.Novikov, M.O'Neill, M.Shatkay, D.Sinclair, N.StarinskyCarleton University T.C.Anderson, P.Jagam, J.Law, I.T.Lawson, R.W.Ollerhead,J.J.Simpson, N.Tagg, J.-X.WangUniversity of Guelph

J.Bigu, J.H.M.Cowan, J.Farine, E.D.Hallman, R.U.Haq,J.Hewett, J.G.Hykawy, G.Jonkmans, S.Luoma, A.Roberge, E.Saettler, M.H.Schwendener, H.Seifert, R.Tafirout, C.J.VirtueLaurentian University Y.D.Chan, X.Chen, M.C.P.Isaac, K.T.Lesko, A.D.Marino,E.B.Norman, C.E.Okada, A.W.P.Poon, S.S.E Rosendahl,A.Schülke, A.R.Smith, R.G.StokstadLawrence Berkeley National Laboratory

M.G.Boulay, T.J.Bowles, S.J.Brice, M.R.Dragowsky,M.M.Fowler, A.S.Hamer, A.Hime, G.G.Miller,R.G.Van de Water, J.B.Wilhelmy, J.M.Wouters Los Alamos National Laboratory

J.D.Anglin, M.Bercovitch, W.F.Davidson, R.S.Storey*

National Research Council of Canada

J.C.Barton, S.Biller, R.A.Black, R.J.Boardman, M.G.Bowler,J.Cameron, B.T.Cleveland, X.Dai, G.Doucas, J.A.Dunmore,A.P.Ferarris, H.Fergani, K.Frame, N.Gagnon, H.Heron, N.A.Jelley, A.B.Knox, M.Lay, W.Locke, J.Lyon, S.Majerus, G.McGregor,M.Moorhead, M.Omori, C.J.Sims, N.W.Tanner, R.K.Taplin,M.Thorman, P.M.Thornewell, P.T.Trent, N.West, J.R.WilsonUniversity of Oxford

E.W.Beier, D.F.Cowen, M.Dunford, E.D.Frank, W.Frati,W.J.Heintzelman, P.T.Keener, J.R.Klein, C.C.M.Kyba, N.McCauley, D.S.McDonald, M.S.Neubauer, F.M.Newcomer, S.M.Oser, V.L Rusu,R.Van Berg, P.WittichUniversity of Pennsylvania R.KouzesPrinceton University

E.Bonvin, M.Chen, E.T.H.Clifford, F.A.Duncan, E.D.Earle,H.C.Evans, G.T.Ewan, R.J.Ford, K.Graham, A.L.Hallin, W.B.Handler, P.J.Harvey, J.D.Hepburn, C.Jillings, H.W.Lee,J.R.Leslie, H.B.Mak, J.Maneira, A.B.McDonald, B.A.Moffat,T.J.Radcliffe, B.C.Robertson, P.SkensvedQueen’s University

D.L.WarkRutherford Appleton Laboratory, University of Sussex

R.L.Helmer, A.J.NobleTRIUMF

Q.R.Ahmad, M.C.Browne, T.V.Bullard, G.A.Cox, P.J.Doe,C.A.Duba, S.R.Elliott, J.A.Formaggio, J.V.Germani,A.A.Hamian, R.Hazama, K.M.Heeger, K.Kazkaz, J.Manor, R.Meijer Drees, J.L.Orrell, R.G.H.Robertson, K.K.Schaffer,M.W.E.Smith, T.D.Steiger, L.C.Stonehill, J.F.Wilkerson University of Washington

The END

Backup Slides

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Global Solar Analysis

Inputs: • 37Cl, latest Gallex/GNO, new SAGE, SK 1258-day day & night spectra• SNO day spectrum (total: CC+NC+ES+background)• SNO night spectrum (total: CC+NC+ES+background)• 8B floats free in fit, hep at 1 SSM

SNO data only Global

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

What will SNO and KamLAND tell us in the future

de Holanda et al., hep-ph/0212270Barger et al., hep-ph/0204253

Alan Poon, EPS HEP 2003, Aachen, Germany (July 2003)

Model Independent Test of MSW

• KamLAND establishes “LMA” region (m2>10-6 eV2)• Use CC/NC (solar model independent) to test for MSW effect in the Sun

Fogli et al.,hep-ph/0211414

MSW offMSW On