Current status of neutrino (oscillation)

experiment

Current status of Current status of neutrino (oscillation) neutrino (oscillation)

experimentexperimentA.A. K. IchikawaK. Ichikawa

KEKKEK

Neutrino Oscillation!

LE

mi2

21

e− L

Emi2

22

e−

|να>=|ν1>cosθ+|ν2>sinθ, α=e,µ,τ

Trabeling distance L

|ν1> cosθ+|ν2> sinθ

= )4

(sin2sin1( 222

ELm∆− θ )

4(sin2sin 222

ELm∆θ|να> +|νβ>

Three Flavor Mixing in Lepton Sector

=

3

2

1CPMMNSVU

ννν

ννν

τ

µ

e

+−++

+−

++

+−++=

−

10000

0010

0

00

001U 1212

1212

1313

1313

2323

2323PMNS cssc

ces

esc

cssc

i

i

δ

δ

νe

νµ

ντ

Weak eigenstates m1

m2

m3

mass eigenstates

=1000e000e

V 2

1

i

i

CPM

α

α

θ12, θ23, θ13+ δ (+2 Majorana phase)

∆m12, ∆m23, ∆m13

What’s difficult w/ neutrino experiment

Cross section is extremely small.

-> Need large mass detector and strong source

Observable is Ψ x σ , while both Ψ and σ are unknown to some extent.

Hence both signal and noise are unknown to some extent.

One note for disappearance

Neutrino flavor is tagged via charged current (CC) interaction.

Ethreshold ~ a few MeV for νe

~ a few 100 MeV for νµ

~ a few GeV for ντ

At Eν < Ethreshold,

that flavor is not observed and recognized as disappearance.

We cannot distinguish disappearance due to Eν<Ethreshold

and that due to sterile neutrino.

LSND -> MiniBooNELSND LSND --> > MiniBooNEMiniBooNEConfliction w/ 3 generation oscillation scenarioConfliction w/ 3 generation oscillation scenario

????Sterile????????Sterile????

LSND & KARMEN Results1993-1997 1990-1995

Appearance of fromeν µν

MiniBooNE@FNAL, USARunning since Sep. 2002

Cerenkov800 tonsmineral oil(6 m radius)

445 tons (fid.) (5m radius)

1280 PMTs10% coverage

8GeVBe Target

Magnetic horn 50m decay absorber 450m dirt Detector

MiniBooNEMiniBooNE, sensitivity, sensitivity

1-2 years

Answer in 2005?

θ12νe->νµ,ντ?

θθ1212ννee-->>ννµµ,ν,νττ??

Solar & reactorSolar & reactor

Solar ν : before SK, SNO & KamLAND

Experiments

pp,pep

CNO

SNU

Kamioka

H2O

1.0 +0.20-0.16

Theory7Be8BHomestake

-1.1

2.56 ±0.23

37Cl

7.6 +1.3

SNU

71 +7-6

71 ±6

71Ga

128 +9-7

SAGE

GALLEX

SNU

0.55±0.08

Observable in Solar neutrino

Flux

Spectral distortion

Day/Night effect

Seasonal variation

SuperKamiokande@Kamioka, Japan

C Scientific American

42m

39m

ν

Water Cherenkovdetector

1000 m underground50,000 ton (22,500 ton fid.)11,146 20 inch PMTs1,885 anti-counter PMTs

Since 1996.

Accident on 2001.

Partial recovery on 2002.

(Full recovery on 2006)

Elastic scattering w/ water target

-> strong directionality, can measure spectrum

Solar Neutrino Flux solor ee +→+ νν

Seasonal variation is consistent w/ (null-oscillation) expectation.

SNO @Ontario, Canadasince Nov. 1999

Inner Shielding 1700 tonnes H2O

Cerenkov detector1000 tonnes D2O

Outer Shield 5300 tonnes H2O

12 mφ Acrylic Vessel

9500 20cm-PMTs 60% coverage

(9438 inward, 91 outward)

Urylon Liner &Radon Seal

6000 m w.e

ν Reactions in SNOES νx+e- νx+e-

• Both SK, SNO• νe + 0.15 (νµ + ντ)• Strong directional sensitivity• Low statics

•Q=1.445 MeV•Good measurement of E(νe)• νe only• Weak directional sensitivity

CC νe+d p+p+e-

• Q=2.22 MeV• νe + νµ + ντ

NC νx+d p+n+νx

• n + d → t + γ (6.3 MeV)… → e−

νen p

pp

e-

νxn p

np

νx

νx

e-

e-

νx

SNO Data Taking Phases

Phase III(3He n counters):Counters in!n capture on 3Hen + 3He->p +tChannels indep.->no correlation Reduced NC systematics

Future

Phase I (pure D2O):306.4 live daysTe>5 MeVR <550 cm2928 eventsn capture on DSingle 6.25 MeVγHigh CC-NC corr.Te constrained

Past

Phase II (salty D2O):254.2 (~400)daysTe>5.5 MeVR <550 cm3055 eventsn capture on ClMultipleγ’s 8.6 MeVHigh CC-NC corr.Te unconstrained

Present

Signal Extraction –Pure D2O phase

5 6 7 8 9 10 11 12 13

Eve

nts

per

500

keV

0

100

200

300

400

500

600

20→

NC + bkgdneutrons

ES

CC

Bkgd

(c)

(MeV)effT

0 0.2 0.4 0.6 0.8 1 1.2

Eve

nts

per

0.1

wid

e bi

n

0

100

200

300

400

500

CCNC + bkgd neutrons

ES

Bkgd

Fidu

cial

Vol

ume

(b)

3

)AV(R/R

-1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8 1

Eve

nts

per

0.05

wid

e bi

n

0

20

40

60

80

100

120

140

160

sunθcos

ESCC

NC + bkgd neutrons

Bkgd

(a)

θe ν

48.045.0 0.45 41.309.005.076.1

+−±=Φ

±±=Φ

µτ

e

Spectrum direction

position

Signal Extraction –Salty D2O phase

KamLAND @KamLAND @KamiokaKamioka, Japan, JapanSince Nov. 2001Since Nov. 2001

Nuclear reactor

detector ννν

ν ν νν ν

ν ν

1.806MeV2M

M)m(ME

p

2p

2en

ν =−+

≥

ν + p → e+ + n, e+ + e- → 2γ (prompt)n + p → d + γ (2.2 MeV) (delayed)

252 eV105

km74 MeV,3−×≈∆⇒

≈≈

m

LEν

Nuclear Reactors in JapanNuclear Reactors in Japan

~80GW

~ 180 km86% of ν eventsfrom ~180 km

Liquid Scintillator1000 tons of

(Dodecane+PC+PPO)

Spherical balloon13 m diameter

135µ thick

Buffer Oil

ContainmentVessel

18 m diameter

Outer DetectorWater Cerenkov

3200 tons225 20-inch PMT

1325 17-inch PMT22% coverage

Former Kamiokasite 2700 m w.e

22νν region by KamLANDregion by KamLAND

θ12 summary

LMA is likely to be the solution to the solar neutrino problem.

-> Precise measurement, understanding of neutrino oscillation (energy dependence, matter effect), CPT test and so on.

θ23νµ−>ντ?

θθ2323ννµµ−−>>ννττ??

Atmospheric & AcceleratorAtmospheric & Accelerator

Super-Kamiokande, again

µ-like

e-like

What’s new from SK

UpdateFlux,ν interactionCherenkov ring fitting toolsCalibration

L/E oscillation analysis

SK-II is running

L/E analysisNeutrino oscillation : Pµµ = 1 – sin22θsin2(1.27 )

Decoherence : Pµµ = 1 – sin22θsin2(1 – e–γx)21

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2 2.5 3 3.5 4log10(L/E)

prob

.(ν µ

→ ν

µ)

Neutrino decay : Pµµ = (cos2θ + sin2θ x exp(– ))2LE

m32τ3

∆m2LE

-> Direct evidence for oscillations

-> Strong constraint to ∆m2

Reconstruct Eν from Eobserved

L from Zenith angle

Select events w/ good ∆(L/E)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1 10 102

103

104

L/E (km/GeV)

Dat

a/P

red

icti

on

(n

ull

osc

illat

ion

)

L/E distribution

Null oscillation MC

Best-ft expectation

1489.2 days FC+PC

First dip is seen as expected by neutrino oscillation

0

50

100

150

200

250

300

1 10 102

103

104

L/E (km/GeV)

Nu

mb

er o

f ev

ents

Best fit expectation w/ systematic errors

Oscillation analysis w/ L/E

K2K experiment@Tsukuba-to-Kamioka, JapanFirst accerelator-based long-baseline neutrino oscillation

experiment to investigate the neutrino oscillation observed in atmospheric neutrinos.

KKEKEK--12GeV PS12GeV PS

SuperSuper--KKamiokandeamiokande

~1%50 %νe /νµ

> 2・10-3 eV210-1 ~10-4eV2∆m2

~ 1.3GeV0.1~100GeVEν

250km(fix.)10~104kmL

K2KAtm.-ν

L=250 kmL=250 km

•• Do Do ννµ µ events decrease ?events decrease ?•• Is Is EEνν spectrum distorted ? spectrum distorted ?

Muon range detector

K2KK2K--II From Mar.1999 ~ Jul.2001Near neutrino detectorsNear neutrino detectors

39m

41.4

mSuperSuper--KamiokandeKamiokande II

Outer detector

Inner detector

1885 8” PMTs

11146 20” PMTs

K2KK2K--IIIIAfter the successful resume of the experiment After the successful resume of the experiment Dec.21,2002~Dec.21,2002~

SuperSuper--KamiokandeKamiokande IIIIInner detector

~5200 PMTs with FRP+Acrylic coverRemove Lead Glass detectorto explore lower energy region

Upgraded near neutrino detectorsUpgraded near neutrino detectors

SciBar detector (Oct.2003~)Upgraded near neutrino detectorsUpgraded near neutrino detectors

Oct.3,2003~Oct.3,2003~

SciBar -Event Gallery-

3 track

???νe

Large energy deposit in Electron Catcher

(NC) π0

vertexCC-QE candidate

0

1

2

3

4

5

6

7

8

9

10

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5Eν

rec

Even

ts

Normalized by area

reconstructed Eν

Expectationw/o oscillation

Best Fit

Allowed region

Oscillation analysis on JuneOscillation analysis on June’’99 ~ July 99 ~ July ’’01 data01 dataUse both Number of events + Spectrum shape

(June ’99 – July ’01) (Nov. ’99 – July ’01)

Null oscillation probability: less than 1%.∆m2=1.5~3.9 x 10-3 eV2 @sin22θ=1(90%CL)

68%90%99%

80.1+6.2-5.4 exp56obs ⇔

Results from K2KResults from K2K--II

Super-Kamiokande events (Jun.1999~Apr.2003)

FC 22.5kt

POT vs events

KS probability = 64.3%

CT *1018 POT

even

ts

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

K2KK2K--IIII+16events+16events

K2KK2K--II56events56events

Search for τ appearance@CNGSCNGS (CerN to Gran Sasso) beam will start on May, 2006.

L=730km, <Eν>=17GeV

Cosmic ray event w/ T600.

ICARUS Liquid Ar TPC

OPERA

Emulsion Hybrid detector

ντcc in DONUT

θ23 summaryPrecise measurement, understanding of

neutrino oscillation (energy dependence) and tau appearance by Super-K is on going.

K2K will confirm neutrino oscillation phenomena by artificially produced neutrino.

Oscillated spectrum?

Coming MINOS and T2K will improve the precision by one order of magnitude.

OPERA and ICARUS w/ CNGS beam will search for the tau appearance.

θ13νµ->νe?

θθ1313ννµµ-->>ννee??

UnknowUnknow parameterparameterReactor & AcceleratorReactor & Accelerator

CHOOZ1996-1998

xe νν → L=1km

5t Liquid ScintillatorH richparaffin

Gd loaded (γ 8MeV)

425 GWth

sin22θ13<0.2

@∆m223=2.0E-3eV2

νe disappearance experiment

3-flavor Oscillation

( )νµ θθ ELmP e /27.1sin2sinsin 213

213

223

2 ∆⋅⋅≈→

( )νµ θθ ELmP x /27.1sin2sincos1 223

223

213

4 ∆⋅⋅−≈→

Oscillation Probabilities when 213

223

212 mmm ∆≈∆<<∆

θ13:νe appearance

θ23 :νµ disappearance

common

m1

m2

m3

δθθ

νννννννν

νµµ

µµ sinsin

2sin4)()(

)()(

13

122

12 ••∆

≈→+→→−→

=E

LmPPPP

Aee

eeCP

δ: CP in νe appearance

10-4

10-3

10-2

10-1

0 0.1 0.2 0.3 0.4 0.5

∆m2

(eV

2 )

K2K(90%CL)

CHOOZ(90%CL)SK atm.νallowed (90%CL)

Search for νe appearance in K2K

1322 2sin

212sin θθµ ≈e

Electron Candidate

= 1-ring e-like fully-contained no-decay-e

2.4 B.G. events expected

1 event observed

θ13 from nowθθ1313 from nowfrom nowAppearance!Appearance!sign of sign of ∆∆mm22!!CP violation!CP violation!

MINOS@FNAL, USAMain Injector Neutrino Oscillation Search

MINOS Far detector at Soudan

8m steel & scintillator tracking calorimeter

5.4 kton total mass.

MINOS status & schedule

~1GeV ν beamKamiokaJ-PARC

(Tokaimura)

0.75MW 50 GeV PS

( conventional ν beam)

Super-K: 22.5 kt

4MW 50 GeV PS

Hyper-K: 1000 kt

Phase-I (0.75MW + Super-Kamiokande) 2009~Phase-II (4MW+Hyper-K) ~ Phase-I × 200 201x?~

T2K @ Tokai=J-PARC to Kamioka=Super-K, Japan

Recent events•• Jun. 2003Jun. 2003:

– Budget request submitted to Monka-sho (MEXT)– 4 year plan

•• Aug.2003Aug.2003– The request went out from MEXT (5 yrs plan) to Ministry of

finance (MOF)•• Oct.2003Oct.2003

– CSTP rated J-PARC ν at lowest rank(CSTP: Council for Science and Technology Policy)

•• Nov. 2003Nov. 2003– Interim Review of the Project was held.– Recommendation: Neutrino program must start immediately.

•• Dec.20,2004Dec.20,2004– Neutrino project on the draft budget from MOF

J-PARC neutrino facility approved!– 5 years project from JFY2004 ~ JFY2009– Start experiment in 2009

Ancient Salt Farm

December, 2003

OA3°

OA2°

OA1°

Off Axis Beam

(ref.: BNL-E889 Proposal)

θTargetHorns Decay Pipe

Super-K.

Quasi Monochromatic Beamx 2~3 intense than NBB

Statistics at SK(OAB 2 deg,1 yr,22.5 kt)

~ 4500 νµ tot ~ 3000 νµ CC νe ~0.2% at νµ peak

~102 x (K2K)

Tuned at oscillation maximum

0

5

10

15

20

25

30

35

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5Reconstructed Eν(GeV)

Expected Signal+BGsin22θ13=0.10sin22θ23=1.0∆m2=0.003eV2

Total BG

BG from νµ+antiνµ

sin22θ13 from νe appearance

totalνeνµνeνµ

36.411.524.90.51.710.712.00.01139.5114.624.90.51.710.712.00.1

Signal + BGSignal

Background in Super-K (as of Oct 25, 2001)sin22θ13

sin22θ13

∆m

2

Off axis 2 deg, 5 years

Off axis 2 deg, 5 yearsat

Sin22θ13>0.006

CH

OO

Z ex

clud

ed

θ13 and CP more futureθθ1313 and CP more futureand CP more future

~10 years later?~10 years later?

JHF-II : 4MW + HK

48m × 50m ×500m,

Total mass = 1 Mton

NuMI off-axis

BNLν

From K.M.Heeger NOON04

Reactor experimentdisappearance of νµ

Sin22θ13 90%C.L. sensitivity

CHOOZ

OPERA

MINOS

?20132012201120102009

ICARUS

Reactor(example)

NuMIoff-axis

T2K

2008200720062005

~0.04~0.006

?

~0.015~0.025

~0.04

~0.06

0.11

~0.006

Summary

OR

Next step

sterile, θ13, sign of ∆m2, CP violation…..

µ+ decay at restprompt e+ track, 20<Ee<60 MeVn capture: np → dγ (2.2MeV)

γ correlated in position and in time with e+

e

eeν

νν

νµπ

µ

µ

+

++ →

800 MeV protons1 mA

6% duty ratio

L = 30 meters

Liquid ScintillatorMineral Oil

CH2167t

1220 PMTCerenkov

π+/π−

µ+/µ−

Cu Beam Dump

Target )( ee νννν µµ

nepe+→ν

LSND @ Los Alamos, USA 1993-1997

Flux

01.181.005.5 +

−=ΦSSM

Energy SpectrumEnergy Spectrum

Consistent with :

• distorted shape @ 93 % C.L.

&• no oscillation shape@ 53% C.L.

20

15

10

5

0

reactor neutrinos geo neutrinos accidentals

25

20

15

10

5

086420

Prompt Energy (MeV)

2.6 MeV(analysis)

KamLAND data no oscillation best-fit oscillation

sin22θ = 1.0 ∆m2= 6.9 x 10-5 eV2

Eve

nts/

0.42

5 M

eV

2.6 MeV

Near Detector upgrade –SciBar-• Extruded scintillator with WLS

fiber readout• Neutrino target is scintillator

itself• 2.5 x 1.3 x 300 cm3 cell• ~15000 channels ν

Extrudedscintillator(15t)

Multi-anodePMT (64 ch.)

Wave-lengthshifting fiber

EM calorimeter

1.7m

3m

3m

Just constructed in this summer!

Search for νe appearance in K2K

Electron Candidation

= 1-ring e-like fully-contained no-decay-e

2.4 B.G. events expected

1 event observed

MINOS θ13 sensitivity