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

ijijijij

ii

i

τττ

μμμ

eee

li

sandcwhere

e

e

cs

sc

iδecs

sccs

sc

UUU

UUU

UUU

U

sin,cos

00

00

001

0

010

0

00

010

001

0

0

001

100

0

0

2/

2/

1313

1313

2323

23231212

1212

321

321

321

3

2

ilil U If neutrinos have mass:

)E

LΔm.(θ)νP(ν eμ

222 271sin2sin

For three neutrinos:

Solar,Reactor Atmos., Accel.

Using the oscillation framework for neutrino flavor change:

For two neutrino oscillation in a vacuum: (valid approximation in many cases)

CP Violating Phase Reactor, Accel Majorana Phases

Range defined for m12, m23

Maki-Nakagawa-Sakata-Pontecorvo (MNSP) matrix

(Double decay only)

Matter Effects – the MSW effect

x

e

x

e Hdt

di

cos2θ

4E

Δmsin2θ

4E

Δm

sin2θ4E

ΔmNG2cos2θ

4E

Δm

H 22

2

eF

2

2

22

22

/2

2sin)2cos(

2sin2sin

mENG eF

m

The extra term arises because 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

Bahcall et al. (2001)

, SNO

Oscillations for Solar Neutrinos

SAGEGNO

ChlorineSK,SNO

pp

7Be pep

Solar Model Flux Calculations

Current Data for e Survival

Matter Interaction Effect:LMA

2005 was a sad year forsolar neutrino physics with

the passing of Hans Bethe and John Bahcall

CNO

Future solar neutrino measurementspp, 7Be, pep, 8B

pp8B

Bahcall & Pena-Garayhep-ph/0305159

Vacuum

LMA

• NEUTRINO PHYSICS

- Confirm matter effects (MSW).

- Improve

- Search for effects of sterile ,Non-Standard Interactions,Mass-varying neutrinos.

• SOLAR PHYSICS

- Accurate measurement of neutrino luminosity (pp, pep).

- Observe CNO neutrinos.• Compare ES, CC• Compare ES, SSM

pep7Be

Unique Signatures in SNO (D2O)

Charged-Current (CC)e+d e-+p+pEthresh = 1.4 MeV

ee onlyonly

Elastic Scattering (ES)x+e- x+e-

x, but enhanced for e

Neutral-Current (NC) x+d x+n+p Ethresh = 2.2 MeV

Equally sensitive to Equally sensitive to e e

3 ways todetect neutrons

Solar Neutrino Physics From SNO

Clear Evidence: Flavor change + active neutrino appearance

Total 8B Solar Neutrino Flux

CC

ES

=e

e + 0.15 ( +

CC

NC

e

e + + =

x CC +ES - CC) x (1/0.15=

x nc=

June 2001 (with SK)

June 2001

April 2002

April 2002

~10%

Sept. 2003March 2005

With saltin SNO

Sept. 2003March 2005

Phase II (salt)July 01 - Sep. 03

Phase III (3He)Nov. 04-Dec. 06

Phase I (D2O)Nov. 99 - May 01

3 neutron (NC) detectionmethods (systematically different)

n captures on2H(n, )3H

Effc. ~14.4% NC and CC separation by energy, radial, and

directional distributions

40 proportional counters

3He(n, p)3HEffc. ~ 30% capture

Measure NC rate with entirely different

detection system.

2 t NaCl. n captures on35Cl(n, )36ClEffc. ~40%

NC and CC separation by event isotropy

36Cl

35Cl+n 8.6 MeV

3H

2H+n 6.25 MeV

n + 3He p + 3H

p3H

5 cm

n

3He

The latest SNO data: 391 live days with salt hep-ex/0502021 March 2005

New Information: Charged Current Energy Spectrum

040.0037.0A OD salt 2 Day-Night Asymmetry assuming ANC=0

Data from Experiments in Operation

)syst.()stat.( 35.2

)syst.()stat.( 94.4

)syst.()stat.( 68.1

15.015.0

22.022.0

38.034.0

21.021.0

08.009.0

06.006.0

ES

NC

CC

)scm10 of units(In 126

122

134029.0

031.0NC

CC sincos)stat.(023.034.0

Improved accuracy

for

Electron neutrinos

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)

CC, NC FLUXESMEASURED

INDEPENDENTLY

Flavor change determined by > 7

- The solarresults define themass hierarchy(m2 > m1) through theMatter interaction (MSW)

- SNO: CC/NC fluxdefines tan2 < 1 (ie Non - Maximal mixing)by more than 5standard deviations

SOLAR ONLY

AFTER NEW

SNO SALT

DATA

SOLAR PLUS

KAMLAND (assuming CPT)

(Reactor ’s)

Large mixing

Angle (LMA)

Region only

LMA for solar predicts very small

spectral distortion, small (~ 3 %) day-night

asymmetry, as observed by SNO, SK

Results from SNO -- Salt Phase

SNO D2O D/N spectraSNO Salt D/N spectraKamLAND 766-daySK-I zenith spectraSAGEGallex/GNOCl/Ar

Oscillation Parameters, 2-D joint 1- boundary

Marginalized 1-D 1- errors

Periodicity in Solar Flux?

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 largerlikelihood ratio (S) with zero

sinusoidal amplitude than the maximum S observed in the fits.

Conclusion: No observedsinusoidal variation at periods

from 1 day to 10 years.

Analysis sensitive to amplitude of 8-10% at 99% C.L..

SNO data 1999-2003

hep-ex/0507079

Orbital Eccentricity

SK: hep-ex/0508053

= 0.021(3) = 0.014(9). Actual: 0.0167

SNO: hep-ex/0507079

• Direct observation (7 ) of neutrino flavor change via an appearance measurement: Beyond the Standard Model for Elementary Particles.

• Direct measurement (10 % accuracy) of total flux of active neutrinos: Strong confirmation of Solar Models.

• The dominant transformation is to active neutrinos: Sterile neutrino fraction is restricted (<~ 13%).

• Clear determination (5.3 ): 12 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.

Summary of SNO results

Present Phase: SNO Phase III

• 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

Neutral-Current Detectors (NCD): An array of 3He proportional counters

40 strings on 1-m grid~440 m total active length

Phase III production data taking began Dec 2004; completion at the end of 2006

Correlations D2O unconstrained D2O constrained Salt unconstrained NCD

NC,CC -0.950 -0.520 -0.521 ~0

CC,ES -0.208 -0.162 -0.156 ~-0.2

ES,NC -0.297 -0.105 -0.064 ~0

Blind Analysis

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

’s from 8Li ’s from 16N and t(p,)4He

252Cf neutrons

6.13 MeV

19.8 MeV

Energy calibrated to ~1.5 %

Throughout detector volume

Optical calibration at 5 wavelengths with the “Laserball”

SNO Energy Calibrations: 25% of running time

+ AmBe, 24Na

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

SNO Physics Program Solar Neutrinos (5 papers to date)

Electron Neutrino FluxTotal Neutrino FluxElectron Neutrino Energy Spectrum DistortionDay/Night effectshep neutrinos (paper in progress)Periodic variations hep-ex/0507079 [Variations < 8% (1 dy to 10 yrs)]

Atmospheric Neutrinos & MuonsDownward going cosmic muon fluxAtmospheric neutrinos: wide angular dependence [Look above horizon]

Supernova Watch (SNEWS) Limit for Solar Electron Antineutrinos

hep-ex/0407029 Nucleon decay (“Invisible” Modes: N ) Phys.Rev.Lett. 92 (2004) [Improve limits by 1000] Supernova Relic Electron Neutrinos

New International Underground Science FacilityAt 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

The New SNOLAB

SNO

NewExcavation

To Date

Cosmic Ray

Muons

Vs

Depth

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

Future low-energy solar experiments

[Nakahata@NOON04]

*

*

* funded

SNOLAB

SNOLAB Dan McKinsey Talk

+

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) ?

pep

SNO CC/NC

m2 = 8.0 × 10−5 eV2

tan2 = 0.45

SSM pep flux:uncertainty ±1.5%

known source → precision test

Survival Probability Rise

sensitive to new physics:• non-standard interactions• solar density perturbations• mass-varying neutrinos• CPT violation• large 13

• sterile neutrino admixture

improves precision on 12

Studying the rise confirms MSW or perhaps shows us new physics

stat + syst + SSM errors estimated

• non-standard interactions

• MSW is linear in GF and limits from -scattering experiments g2 aren’t that restrictive

• mass-varying neutrinos

Friedland, Lunardini, Peña-Garay, hep-ph/0402266

Barger, Huber, Marfatia, hep-ph/0502196

pep solar neutrinos are at the “sweet spot” to test for new physics

New Physics NC non-standard Lagrangian

Miranda, Tórtola, Valle, hep-ph/0406280

Sterile Neutrinos: de Holanda and Smirnov hep-ph/0307266

3600 pep/year/kton >0.8 MeV

2300 CNO/year/kton >0.8 MeV

7Be solar neutrinos

using BS05(OP)and best-fit LMA

Event Rates (Oscillated)

resolution with 450 photoelectrons/MeV

these plots from the KamLAND proposal muon rate in KamLAND: 26,000 d−1 compared with SNO: 70 d−1

11C Cosmogenic Background

KamLAND (7Be phase)

•Elastic scattering:x+ e- → x+ e-

• R&D work focus on reducing radioactive backgrounds in the liquid scintillator.

238U232Th 40K 85Kr210Pb

(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 Bq/m3

~10-25 g/g

impurities present goal reduction

OK OK 10-2

10-6

10-5

distillation purge

< 10-2

< 10-5

< 10-4

< 10-5

Kamland Purification System to be installed in 2006

pep

Default Scintillator Identified

• Linear Alkyl Benzene (LAB) has the smallest scattering of all scintillating solvents investigated

• LAB has the best acrylic compatibility of all solvents investigated

• density = 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

Like Ivory SNOWSoap:

(99 + 44/100) %Pure.

It Floats!

Geo-Neutrino SignalGeo-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

SNO+ geo-neutrinos and reactor background KamLAND geo-neutrino detection…July 28, 2005 in Nature

based on Rothschild, Chen, CalapriceGeophys. Res. Lett. 25, 1083 (1998)

geo- in SNO+

KamLAND

0: 1057 events peryear with 1% naturalNd-loaded liquidscintillator in SNO++.

Simulationassuming lightoutput similar toKamland.

SNO++ (Nd Double Beta Decay)

Very preliminarysimulation:one year of datam= 0.15 eV

Queen’sM. 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

LaurentianD. Hallman, C. Virtue

SNOLABB. Cleveland, R. Ford, I. Lawson

Brookhaven National LabA. Garnov, D. Hahn, M. Yeh

Los Alamos National Lab A. HimeLIP Lisbon

J. Maneira

• potential collaborators from outside SNO (Italy, Germany, Russia) have indicated some interest

new collaborators welcome

SNO+ Collaboration

A subset of the SNO collaboration will continue with SNO+

We are working on a SNO+ proposal to be submitted this fall.

* Principal Investigator

Some other fun SNOLAB experiments as time permits

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

scintillation pulse-shape analysis for discrimination of e- vs nuclear recoils-> no electron-drift

http://arxiv.org/astro-ph/0411358

DEAP : Dark-matter Experiment with Argon PSD

Background rejection with LAr (simulation) [Mark Boulay]

From simulation,rejection > 108

@ 10 keV(>>!)

108 simulated e-’s

100 simulatedWIMPs

Discrimination in liquid argon from DEAP-0

O(1in 105) consistentwith room background(preliminary)

<pe> = 60 corresponds to 10 keV with 75% coverage

<pe> = 60

•Final analysis and systematics evaluation being done

preliminary

DEAP-0DEAP- 1 (2 kg)

Is under Construction atQueen’s. To be

Sited in SNOLABIn 2006

Spin Independent Interaction

M.G. Boulay & A. Hime, astro-ph/0411358

} Where we Are

} Some Future Expts.

Liquid Ar scintillation

Minimal Super-

Symmetric Models

Montreal, Queen’s

Indiana, Pisa, BTI

Fluorine is very sensitive for the spin-dependent interaction

SPIN - DEPENDENT

INTERACTION

1 kg

10 kg

100 kg

20 g: hep-ex/0502028

2 kg to be run in 2006

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.

Mats Sundin

Another Canada – Sweden connection: Hockey

Congratulations to Sweden

Olympic Hockey Champions!