new results from the salt phase of sno kathryn miknaitis center for experimental nuclear physics and...
TRANSCRIPT
![Page 1: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/1.jpg)
New Results from the Salt Phase of SNO
Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington
For the
Sudbury Neutrino Observatory
In this talk:
•SNO overview•Salt phase overview
•New solar neutrino flux, spectrum, and day-night
asymmetry results from 391 days of salt data!
The Sudbury Neutrino Observatory
![Page 2: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/2.jpg)
The SNO Detector
Acrylic vessel (AV), 12 m diam.
1700 tonnes H2O inner shielding
1000 tonnes D2O
6800 feet (~2km) underground
5300 tonnes H2O outer shielding
~9500 PMTs, 54% coverage
![Page 3: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/3.jpg)
SNO’s Three Reactions
-eppd (CC) eCharged Current:
Neutral Current:
npd (NC) xx
Elastic Scattering:
-- ee (ES) xx
•Detect the e-
• energy spectrum
• Weak directional sensitivity
e
•Detect the n through secondary capture
• No directional or neutrino energy info
•Detect the e-
•Mainly sensitive to
•Highly directional
e
![Page 4: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/4.jpg)
-- ee (ES) xx
npd (NC) x x
-eppd (CC) e
NCx
CCESCCx
)154.0/1()(
Solar Neutrino Physics with SNO (I)
Measurement of the 8B Solar Neutrino Flux:
Flavor change:
)(154.0
e
e
ES
CC
e
e
NC
CC
![Page 5: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/5.jpg)
Solar Neutrino Physics with SNO (II)
Spectrum
6 MeV 13 MeV
No.
of
CC
eve
nts
Increasing Δm2
Day
Night
ee
eee DN
DNA
)(2
Day-Night Asymmetry:
MSW Signatures MSW Parameter Constraints
hep-
ph/0
4063
28 J
uly
21 2
004
Ban
dyop
adhy
ay,
Cho
ubey
, Gos
wam
i, P
etco
v, a
nd R
oy
Global analysis of solar neutrino and KamLAND data from 2004
SNO measurements of CC/NC, spectrum, and day-night
asymmetry contribute to MSW constraints
“LMA region”
![Page 6: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/6.jpg)
Pure D2O
Salt 3He
Nov. 99 - May 01 July 01 - Sep. 03 Nov 04 - Dec. 06
γγ
γ
35Cl 36Cl
36Cl*
nγ
2H 3H
3H*
n
n captures on deuterium
σ = 0.0005b
6.25 MeV γ
n captures on chlorine
σ = 44b
8.6 MeV multiple γs
n captures on 3He in discrete prop.
counter array
σ = 5330b
0.764 MeV
n + 3He p + 3H
p3H
5 cm
n
3HePRL 87, 071301, 2001PRL 89, 011301, 2002PRL 89, 011302, 2002
PRL 92, 181301, 2004(for first 254 days) nucl-ex/0502021391-DAY RESULTS!
npd (NC) xx Three ways to catch that neutron!
![Page 7: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/7.jpg)
1. Higher capture cross-section means more neutrons detected
2. Boosts energy of NC events further above analysis threshold
…
3H 36Cl
2H+n
35Cl+n
6.25 MeV
= 0.0005 b = 44 b
8.6 MeVAdvantages of Salty D2O (I)
![Page 8: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/8.jpg)
Define an “isotropy parameter” based on Legendre polynomials in θij
3. Multiple gammas for NC means light is more isotropic than for CC, ES
ij
4114 4
)(cos
jiijll P
Advantages of Salty D2O (II)
Statistical separation of CC, NC events with no constraint on the CC spectrum shape
![Page 9: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/9.jpg)
20
Energy Isotropy
Direction Radius
![Page 10: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/10.jpg)
Extracted Events:
391- day salt results!
4722 events, r<550cm, Teff>5.5MeV
(Patience! Energy spectrum coming up soon!)
CC: 2176 ± 78
NC: 2010 ± 85
ES: 279 ± 26
External neutrons: 128 ± 42
Backgrounds fixed in fit: 128
![Page 11: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/11.jpg)
)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
391- day salt results!
)scm10
of units(In 126
029.0031.0)stat.(023.0340.0
NC
CC
![Page 12: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/12.jpg)
Systematics
Dominant systematic uncertainties for the shape-unconstrained analysis:
Energy scale -0.9% +1.0%
-3.3% +3.8%
-1.6% +1.9%
β14 mean -4.0% +3.7%
-3.6% +4.5%
-1.2% +1.3%
Radial scale -2.6% +2.5%
-3.0% +3.3%
-2.6% +3.0%
Angular Res. -0.4% +0.4%
-0.2% +0.2%
-5.1% +5.1%
CC NC ES
For spectrum analysis:
Systematic uncertainties evaluated
in each extracted CC energy bin
![Page 13: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/13.jpg)
CC Spectrum
Extracted CC spectrum with statistical and systematic
uncertainties
Extracted CC spectrum with statistical uncertainties,
compared to model predictions:
CC spectrum consistent with LMA, undistorted 8B
![Page 14: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/14.jpg)
Systematics for the Day-Night Analysis
DN Correlated Uncertainties: overall energy scale uncertainty… “cancel” in asymmetry ratio
Differential Uncertainties: time variations (diurnal and long term) evaluate with in-situ techniques geometric uncertainties evaluate with calibration data
Classes of Events Used to Limit Diurnal Variations:
“Muon Followers” – neutrons induced by cosmic ray muons“Hot Spot” - radioactive spot on the acrylic vessel (AV)D2O radioactivity - uranium and thorium in the D2OH2O radioactivity - uranium and thorium in the H2OAV radioactivity - radioactive decays in the acrylicPMT beta - gammas from decays in the PMTs
![Page 15: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/15.jpg)
ACC= -0.056 ± 0.074 (stat.) ± 0.051 (syst.)
ANC= 0.042 ± 0.086(stat.) ± 0.067 (syst.)
AES= 0.146 ± 0.198(stat.) ± 0.032 (syst.)
(CC, ES spectrum shapes unconstrained in this analysis)
DN
DNA
)(2Day-Night Asymmetries (I)
ACC and ANC are correlated (ρ = -0.532)
In standard neutrino oscillations, ANC should
be zero…
![Page 16: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/16.jpg)
Day-Night Asymmetries (II)
ACC= -0.037 ± 0.063(stat.) ±0.032(syst.)
AES= 0.153 ± 0.198(stat.) ±0.030(syst.)
Constraining ANC to be zero:
In the pure-D2O phase,
(shape constrained, ANC constrained)
013.0012.0e 049.0070.0A
DN
DNA
)(2
Combine with analogous ACC from the salt phase:
Convert Super-Kamiokande AES to Ae, and combine with SNO:
040.0037.0A OD salt 2
027.0035.0A SK SNO
![Page 17: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/17.jpg)
MSW Constraints
Previous global analysis of solar neutrino data
Global Solar, with
new salt results
Global Solar + KamLAND 766
ton-year data
09.007.0
2256.04.0
2
09.008.0
2254.43.2
2
45.0tan ,eV100.8 b)
45.0tan ,eV105.6 a)
m
m
![Page 18: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/18.jpg)
Detection Principle
2H + x p + n + x - 2.22 MeV (NC)
3He + n p + 3H + 0.76 MeV
x
n
40 Strings on 1-m grid
440 m total active length
NCD
PMT
SNO Phase III (NCD Phase)
3He Proportional Counters (“NC Detectors”) now installed Production data taking underway
Physics Motivation
Event-by-event separation. Measure NC and CC in separate data streams.
Different systematic uncertainties than neutron capture on NaCl.
![Page 19: New Results from the Salt Phase of SNO Kathryn Miknaitis Center for Experimental Nuclear Physics and Astrophysics, Univ. of Washington For the Sudbury](https://reader035.vdocuments.us/reader035/viewer/2022062803/56649f525503460f94c76ca5/html5/thumbnails/19.jpg)
Conclusions
• Results from full 391-day salt phase available nucl-ex/0502021
• Solar neutrino flux results confirm and improve previous results
• CC spectrum presented, consistent with LMA prediction (also consistent with no distortion)
• Day-Night asymmetries consistent with LMA prediction (also with no asymmetry)
•MSW mixing parameters:
09.007.0
2256.04.0
2 45.0tan ,eV100.8
m