michael smy uc irvine solar and atmospheric neutrinos 8 th international workshop on neutrino...
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Michael SmyUC Irvine
Solar and Atmospheric NeutrinosSolar and Atmospheric Neutrinos
8th International Workshop
on Neutrino Factories,
Superbeams & BetabeamsIrvine, California, August 25th 2006
• 50kt Water Cherenkov Detector with 11,146 20” PMTs• located in Kamioka mine at 36.430N latitude and 137.310
longitude ~2,400 m.w.e underground
Super-KamiokandeSuper-Kamiokande
• April 1996-July 2001: (SK-I) Accident in November 2001 during maintenance Jan. 2003-Oct. 2005: SK-II (half PMT density) July 2006 – (SK-III)
• many physics topics; solar, atmospheric & accelerator ’s, proton decay Courtesy Y. Oyama
Super-K Is Repaired!Super-K Is Repaired!
Michael Smy, UC Irvine
began in fall 2005…
…now finished!
Village of Dou near Atotsu Mine Entrance Mozumi Mine Entrance
…despitesomeweatherproblems!
Sudbury Neutrino ObservatorySudbury Neutrino Observatory• 1kt Heavy Water+ 7kt Light
Water Cherenkov Detector with 9,438 8” PMTs
• located in Creighton mine at 46.470N latitude and 81.20W longitude ~6,000 m.w.e underground
• November 1999-June 2001 (measurement with pure D2O) June 2001-October 2003 (NaCl dissolved to improve neutron eapture efficiency) ~April 2004- (with neutral current detector array)
• Mainly solar neutrinos
Other ExperimentsOther ExperimentsHomestakeHomestake Soudan 2Soudan 2 MACROMACRO
SAGESAGE
Solar Solar
Atmospheric Atmospheric Atmospheric Atmospheric
Solar Solar Solar Solar Solar Solar
Neutrino Sources and OscillationsNeutrino Sources and Oscillations
Mixing-Matrix:
Michael Smy, UC Irvine
2Hp
n
e+
p
I Solar NeutrinosI Solar Neutrinos
Michael Smy, UC Irvine
ne-
p
p
2H
p3He
p3He
7Be
4He
7Be4He 8B
p
e-
7Li
e+
4He
4He
*
8Be
4He
4He
*
8Be
p
3He
4He
pn
e+
Solar Neutrino DetectionSolar Neutrino Detection
- e only- D: Q = 1.445 MeV; good measurement of e energy, some direction info (1 – 1/3 cos)- Cl: Q=0.8 MeV (radio-chemical)- Ga: Q=0.233 MeV (radio-chemical)
- equal cross section for all active types- Q = 2.22 MeV - measures total 8B flux from the Sun
NCxx
npD
ES e−e− x
- mainly sensitive to e, some and
- strong directional sensitivity
CC e−(n-1,p+1)(n,p) e
x
Based on: K. Graham, ICHEP06
in SNO
in SNO
+
in Cherenkov Detector
14
CC-NC separation
cossun
CCNCES
SNO Signal ExtractionSNO Signal Extraction• maximum likelihood fit of model PDF’s to data
• event variables R (radial position) 14(isotropy) cossun and E(energy)
ES separation
don’t use E “energy-unconstrained” fit out CC spectrum!K. Graham, ICHEP06
SNO Results from NaCl PhaseSNO Results from NaCl Phase. 0.08
0.09
.
. 0.380.34
1.68 0.06( .) ( .)
2.35 0.22( .) 0.15( .)
4.94 0.21( .) ( .)
II uncCC
II uncES
II uncNC
stat syst
stat syst
stat syst
Flux Results
CC 2176+/-78 ES 279+/-26 NC 2010+/-85#
EV
EN
TS
4722 candidate events4722 candidate events
391 live days391 live days
0.0290.0310.34 0.023(stat.)CC
NC
Neutrino Flavour Change!
2salt D OA 0.037 0.040 Day/Night Asymmetry
Based on: K. Graham, ICHEP06
Solar Neutrino Solar Neutrino Problem Explained by Problem Explained by SNO and Super-K as SNO and Super-K as
Neutrino Flavor Neutrino Flavor Conversion!Conversion!
Recoil Electron SpectrumRecoil Electron Spectrum
Michael Smy, UC Irvine
88B B MC only MC only 88B B MC only MC only
8B=2.33x106/cm2shep=15x103/cm2s
MC:
ADN=-1.8±1.6±1.2% ADN=-6.3±4.3%(stat)
Solar 95%
99.73% KamLAND
Solar+KamLAND
Michael Smy, UC Irvine
Solar Neutrino Oscillation ParametersSolar Neutrino Oscillation Parameters
Solar Neutrino Future MeasurementsSolar Neutrino Future Measurements• SNO NCD phase will produce smaller error on NC• Lower energy real-time 8B neutrino measurement in
SK-III (and SNO) studies transition from vacuum oscillation to matter-dominated oscillations
• Borexino (and KamLAND) measure 7Be flux• SNO+ looks at pep flux • various projects to measure pp flux in real time
Atmosph. Atmosph. Oscillations Oscillations• 1489 live days of SK-I and 804
live days of SK-II• only muon-like single ring events• cut out low energy events and
events near horizon (poor resolution in L): uncertainty in L/E is set to be <70%
• best fit ↔: sin22=1.00, m2=2.3x10-3eV2, 2=83.9/83dof
• -decay: 2=23.2 or 4.8• -decoher.: 2=27.6 or 5.3
oscill.
decay decoh.
Michael Smy, UC Irvine
All SK Atmospheric All SK Atmospheric Data Samples Data Samples
FC1ringe-like
FCmringe-like
FC1ring-like
FCmring-like
PCstop
PCthru
up-stop
Plep
Sub
-GeV
Mult
i-G
eV
CC e CC
38 event type and mom. binsx 10 zenith bins x 2 exp.
760 bins!
up-thru
up-show.
• slightly slightly better constraint on mixing angle…• … but solar osc. terms affects electron samples• true, even if 13=0• especially affects deviation from max. mixing• include solar term• best-fit : sin2 23 = 0.52 (sin2 223 = 0.9984)
Best Fit: m2 = 2.5 x 10-3 eV2
sin2 2 = 1.00
2 = 839.7 / 755 dof (18%)
Preliminary
Preliminary
Michael Smy, UC Irvine
Zenith angle distributions (SK-I + SK-II)Zenith angle distributions (SK-I + SK-II)
Sub-GeV e-like Sub-GeV -like
Multi-GeV e-like Multi-GeV -like
multi-ring e-like multi-ring -like
PC stopping PC thru-going
UP throughnon-showering
UP stopping
showering
data MC (no osc.)MC (best-fit w/ solar terms)
Preliminary
Michael Smy, UC Irvine
Three Flavour Oscillation AnalysisThree Flavour Oscillation Analysis
1489d; Normal Hierarchy 1489d; Inverse Hierarchy
Other Atmospheric Other Atmospheric Measurements Measurements
PRD 72, 052005 (2005)PRD 72, 052005 (2005)
Future Atmospheric Future Atmospheric MeasurementsMeasurements
• SK-III will improve L/E measurements and appearance analaysis
• MINOS distinguishes atmospheric neutrinos from antineutrinos
• INO, a 50kt magnet. iron experiment
A. Samanta, ICTP 2006/A. Dighe, ICHEP 2006
Magnetic field ~ 1 Tesla along y-direction
P. Litchfield, Neutrino 2006