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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:. - PowerPoint PPT Presentation
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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
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1313
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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!