1

Recent Results from Neutrino Experiments and Plans for the Neutrino Super Beam in Japan

Discovery of neutrino oscillations finite neutrino masses (2 and 3) (1998 – present)Small as expected

Mixing among neutrino flavors expectedQuark mixing implies small mixing

Y.Totsuka, KEKNSS-2003, 031021

2

e

( ) =

1

2

3

( )Ue1

U1

U1

( Ue2

U2

U2

Ue3

U3

U3

)

c12c13 s12c13 s13e-i

-s12c23-c12s13s23e-i c12c23-s12s13s23e-i c13s23

s12s23-c12s13c23e-i -c12s23-s12s13c23e-i c13s23

U (Maki-Nakagawa-Sakata Matrix) =

sij=sinij, cij=cosij, =CP

Mixing matrix

( )

Free moving states(mass eigenstates)

Interacting states

Discovery of large mixing angles, 23 and 12

3

p, HeAtmosphere

Atmospheric neutrinos - I

e

Earth

Super-K

±

±

e±

Expected event rate is uncertain by ~15% : e = 2 : 1 (low energy) known better than 5% Up-down symmetry for E > 1 GeV

4

４０ｍ

４１．４ｍ

Super-Kamiokande (1996)

1996-50000ton water11146 50cm PMT (40% photo coverage)1000m undergroundMin det. energy ~ 5 MeVBasic reactions

+ N + Xe + N e + X

5

SK-II Cosmic ray muon sample

20inch PMT with Acrylic + FRP vessel

Super-Kamiokande II Accident on Nov 12, 2001 Repaired and restarted in Dec, 2002 Inner detector with ~5200 20” PMTs Outer detector with 1885 8” PMTs

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2=170.8/170 d.o.f. at (sin2223, m232)=(1.00, 2.0x10-3eV2)

2=445.2/172 d.o.f. (null oscillation)

1489 day FC+PC data + 1646 day upward going muon data

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Allowed region of the oscillation parameters

Assuming oscillation

Best fit 2

min = 170.8/170 d.o.fat (sin2223 m23

2) = (1.0, 2.0 x 10-3 eV2)

90% CL allowed regionsin2223> 0.91.3x10-3 < m23

2 <3.0x10-3 (eV2)

Assuming null oscillation 2 = 445.2/172 d.o.f

(complete SK-I dataset)

Soudan-2

MACRO

Super-K68% CL90% CL99% CL

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K2K

250km

Long baseline neutrino oscillation experiment

12 GeV PS at KEKNeutrino beamline

<E> ~ 1.3GeV

98% purityBeam monitors and nea

r detectorbeam direction measurement flux and spectrum

Far detector flux and spectrum

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Best fit 1R spectrum & Nsk

Best fit point (sin2223 , m232) 　 =

(1.0, 2.8x10-3eV2) KS test prob.(shape): 79% NSK=54 (Obs.=56)

Very good agreement in shape & NSK with atmospheric neutrinos

Expected w/o oscillationNormalized w/o oscillationNormalized with best fit oscillation

Total number of obs. Events: 56 16 (Jan03-Apr03)

Expected w/o oscillation: 80.6 +7.3-8.0 24 +2.3-2.1

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Comparison with SK atm observation

K2K(1R shape+NSK) SK (FC+PC+up)

90%CL

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Solar image

12

SNO: e e (ES); ed epp (CC); d pn, Cl(n,)Cl, (NC)

Electronics hut Control room

1000

to

n h

eavy

wat

er

(12m

ac

rylic

ves

sel)

9456 of 8 inch PMTs

INCO’s Creighnton mineSudbury, ON, Canada

2km

SNO

1700+5300 ton light water(17.8m stainless steel support, 34mh x 22m barrel-shaped cavity)

(6010mwe)

photo coverage 55% (R<7m) cosmic ray muons ~70 events/day fiducial volume 0.7kt (R,5.5m) Trigger rate (data) 6~8Hz

(~2MeV threshold) Trigger efficiency 100%@~3MeV From compton e- from 16N source (~5 MeV)

vertex resolution 16cm energy resolution 16% angular resolution 27℃

NaCl in D2O

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CC = e

ES = e +0.154 ,

NC = e + ,

SNO CC = 1.7+-0.05+-0.09 ES = 2.39 +-0.12 NC = 5.09

SK ES = 2.32+-0.03

Evidence for an active non-e component ！

[x106/cm2/s]

Super-K + SNO combined (as of 2002)

+0.24- 0.23+0.44 +0.46- 0.43 - 0.43

+0.08- 0.07

SKES

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SNO rates and day/night spectra and Super-K zenith spectra

e oscillation

-3

-4

-5

-6

-7

-8

-9

-10

-11

log

m

2 (e

V2 )

-4 -3 -2 -1 0 1

Log tan2

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Kam-LAND

1000m3 liquid scintillator3000m3 oil+water shield1300 17-inch PMTs + 600 20-inch PMTsAnti-e from reactors (L~170km)Detect e+ from e + p e+ + n (Eth = 1.8 MeV)Observation started on 22 Jan 2002

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Kam-LAND result

145.1 live days, 162 ton year exposure Te > 2.6 MeV, 86.8+-5.6 ev expected 56 ev observed with 1 BG estimated

Te > 0.9MeV124.8+-7.5 ev expected86 ev observed with 2.9 +-1.1BG estimated

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KamLAND confirms the LMA solution!

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FIG. 5: Global neutrino oscillation contours. (a) Solar global: D2O day and night spectra, salt CC, NC, ES fluxes, SK, Cl, Ga. The best-fit point is m2 = 6.5 × 10-5, tan2 = 0.40, fB = 1.04, with 2/d.o.f.=70.2/81. (b) Solar global + KamLAND. The best-fit point is m2 = 7.1 × 10-5, tan2 = 0.41, fB = 1.02. In both (a) and (b) the 8B flux is free and the hep flux is fixed. fB = 8B flux measured / SSM.

Nucl-ex/0309004v1 6Sep2003

SNO

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ντ

νe νμ

31？

CP?

Atm

ospheric neutrinos

Solar neutrinos

K2K

neutrinosm

23 2 = 1.3 - 3.0×10-3 eV

2

sin22

23 = 0.9 – 1.0

m122 = 6 - 9×10-5 eV2

sin2212 = 0.7 – 0.9

KamLAND

What to do next

Measure 31 and m31

2 (~ m232)

m12

2, m232, 12, 23 precisely

Quarks:sin2212 = 0.188 +-0.007sin2223 = 0.0064+-0.0010

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e , electron appearance

P(e) = 4c132s13

2s232 sin2(m31

2L/4E)(1 + 2a(1-2s132)/m31

2)

+ 8c132s12s13s23(c12c23 cos – s12s13s23)

×cos(m232L/4E) sin(m31

2L/4E) sin(m212L/4E)

- 8c132c12c23s12s13s23 sin

×sin(m232L/4E) sin(m31

2L/4E) sin(m212L/4E)

+ 4s122c13

2(c122c23

2 + s122s23

2s132

- 2c12c23s12s23s13 cos) sin2(m212L/4E)

-8c132s13

2s232(1 – 2s13

2)(aL/4E)

×cos(m232L/4E) sin(m31

2L/4E) ,

where a [eV2] = 2√2GFneE = 7.6×10-5 [g/cm3] E [GeV] , red terms change sign for anti-neutrinosP( e) – P( e)

P( e) + P( e)～ m12

2L 4E

sin212

sin13

sinACP =

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Strategy and Sensitivity Goal (Phase I)

~ 5 yearsPrecisely measure 23 and m23

2. e appearance search

Sensitivity goalssin2223 ~ 0.01m23

2 < 1x10-4 eV2

sin2213 ~ 0.006 (90% CL)

Study neutrino interactions at the near detector

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T2K (Tokai-to-Kamioka)

J-PARCHyper-Kamiokande

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J-PARC

Joint Project by KEK and JAERI 3 GeV RCS: spallation-neutron and muon sources

Life and material sciences 50 GeV MR: slow and fast extracted protons

Kaon physics Neutrino physics (long baseline oscillations)

LINAC: intense proton source ADS

(180 MeV,

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25

injection energy 　　　 400 MeV （ 180 MeV ） extraction energy 　　　 3 GeV harmonic number 　 ２ repetition rate 　　　　　　 25 Hz # of protons / pulse 　　　 0.83 E14 average beam current 　 333μA beam power 　　　　　 1 MW

3 GeV RCS

Magnetic alloy cavity

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50 GeV MR

Beam energy: 50 GeV (40 at phase 1)

1 cycle: 3.53s 8 bunches in 9RF buckets Bunch spacing: 598ns Spill width ~ 5s Bunch length ~ 36ns (±3

) 6ns (1

# of protons: 3.3×1014 ppp

Beam current: 15A (slow extraction)

Rf frequency: 1.68 (inj.) – 1.73 (ext.) MHz

flux* at SK = 1.9×107 / cm2yr(1yr = 1021 pot: 123 days at .75MW)

*2.5°Off Axis, 130m decay pipe

3.53s

1.9s

fast

Injection : 0.17sacceleration : 1.96sextraction : 0.7 scurrent down : 0.7 stotal: : 3.53s

slow

0.17

1.96 0.7

0.7

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600MeV Linac

3GeV PS

50GeV PS

N

Near Detector (280m)Neutrino Beam Line

To Super-Kamiokande(295km away)

Neutrino beam line

Construction2001 ～ 2007

JHF MINOS K2K

E(GeV) 50 120 12

Int.(1012ppp) 330 40 6

Rate(Hz) 0.3 0.53 0.45

Power(MW) 0.75 0.41 0.0052

JAERI@Tokai-mura(60km N.E. of KEK)

(Approval in Dec.2000)

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Off Axis Beam

WBB with a misaligned beam line from the det. axis High intensity at low energy: 4500 int./22.5kt/yr Contamination e: 0.8%(0.2% @ peak)

Decay Kinematics

E (GeV)

E

(Ge

V)

0 0.4 0.8 1.2 1.6 2 E (GeV)

2x10-3eV2, L = 295km

p

140m0m 280m 2 km 295 km

on-axis

off-axis

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Fast extraction section

neutrino beamline

30FQ

1F

H1

R104433

R107700R106400

R100400R99600

Arc Sectionco

mbi

ned

func

tion

SC m

agne

ts

ORDipole

Quadrupole Combined

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Focusing Section

solid graphite, 30mm in diam, 900mm long

Target station

32

100 cm100 cm90

0

472

2500

1400

2000

809

Horn system

I=~300kA, three short horns Need to tolerate big heat load from radiation Stress analysis is in progress

Carbon target

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空隙（サービスエリア）

TP+11.8m(0.244Sv/h)

土盛り

TP-1.1m TP-1.1m

0.07Sv/h for 1W/m line

(ターゲット・ステーション 地下レベル）

断面図

FQ3AFH2 FQ3B FQ4 FV1 FV2

放射化物保管室

1.40

TS上屋

2.11

3NBT (TP+8m)レベル

3NBT

コンクリート

コンクリート

土盛り

コンクリート

コンクリート

μ ピット機械室( )半地下

汚染検査室

FL=TP-14.3

遮蔽ブロック

Side View

Top view

4MW beam can be accepted.

max.120o

(half year continuous operation)

(Temperature is controllable under 100o by intermittent operation)

Decay Volume

Water cooling pipe

50o

14o

~3.5deg

130m from target

To Super-K~1.3deg

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Near detector at 2km from the target

9.2m

16.2m

8m

4m

Total mass : 1077ton

Fid. Mass : 100ton

Near detector should look like

Far detector looks like

beam

35

0.28km

Far/near ratio (OA 2deg)spectrum

0.28km

1.5km

295km

2.0km

36

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Strategy and Sensitivity Goal (Phase II)

Intensity upgrade to 4 MW 1 Mton far detector, Hyper-Kamiokande Search for CP violation

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Hyper-Kamiokande (1Mt water) Precision neutrino oscillation study Proton decay search

R&D (complete in 2 years) Cavity excavation and its stability New light detector: Hybrid Photo-

Detector, HPD (50cm)

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Sensitivity (3) to CPV (T2K Phase II)

Chooz excluded@m31~3x10-3eV2

>~27deg

>~14deg

Preliminary

4MW, 1Mt Fid.Vol.2yr for

6.8yr for

T2K1 3 discoverym21=5x10-5eV2

12=/8m32=m31=3x10-3eV2

23=/4

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Conclusions

Rapid progress in measuring masses and mixing of neutrinosm23

2 = 1.3 - 3.0×10-3 eV2, sin2223 = 0.9 – 1.0m12

2 = 6 - 9×10-5 eV2, sin2212 = 0.7 – 0.9Their precisions need to be improved

23 and are still unknown

J-PARC can produce beam 100 times stronger than K2K (proton beam power; 0.75 MW)Sensitivities; sin2231 > 0.006 (90%CL)

If 31 measured, a further upgrade will be consideredproton beam power; 4 MW1 Mton Hyper-KA lot of uncertainties in future

Linear collider, budget deficit, etc

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Supplement

42

JSNS23 neutron beam lines