michael smy uc irvine solar and atmospheric neutrinos 8 th international workshop on neutrino...

Michael SmyUC Irvine

Solar and Atmospheric NeutrinosSolar and Atmospheric Neutrinos

8th International Workshop

on Neutrino Factories,

Superbeams & BetabeamsIrvine, California, August 25th 2006

http://antwrp.gsfc.nasa.gov/apod/image/9710/skam_icrr_big.jpg

Cast of CharactersCast of Characters

• 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:


2Hp

n

e+

p

I Solar NeutrinosI Solar Neutrinos


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

Solar Solar Spectrum from Solar Model Spectrum from Solar Model


KamLAND

Solar Solar Candidates above 5 MeV Candidates above 5 MeV


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

Solar Solar Problem Problem


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


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


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)

SNO CC SpectrumSNO CC Spectrum

no significant sterile or NSI effects


Solar 95%

99.73% KamLAND

Solar+KamLAND


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

IIII AtmosphericAtmospheric Neutrinos/NeutrinoNeutrinos/Neutrino BeamsBeams


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.


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


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


Three Flavour Oscillation AnalysisThree Flavour Oscillation Analysis

1489d; Normal Hierarchy 1489d; Inverse Hierarchy

Sterile Admixture LimitSterile Admixture Limit

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

ConclusionConclusion• we learned a lot about neutrino oscillations

from solar and atmospheric neutrinos (everything we know, except m2

12!)

• still not finished, so stay tuned

michael smy uc irvine solar and atmospheric neutrinos 8 th international workshop on neutrino...

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