1

JHFnu (phase I) neutrino oscillation experiment

For JHF-SK Neutrino Experiment collaboration

Atsuko Kondo-IchikawaKEK

NOON03＠ Kanazawa　 Feb. 11, 2003

2

12, 23, 13

+

m212, m2

23

MNS (Maki-Nakagawa-Sakata) matrix

Three Flavor Mixing

3

3-flavor Oscillation

ELmP e /27.1sin2sinsin 213

213

223

2

ELmP x /27.1sin2sincos1 223

223

213

4

Oscillation Probabilities when 213

223

212 mmm

e appearance

disappearance

common

m1

m2

m3

sinsin

2sin

4)()(

)()(

13

122

12

E

Lm

PP

PPA

ee

eeCP

CP in e appearance

4

Strategy

High statistics by high intensity beam Tune E at oscillation maximum Narrow band beam to reduce BG Sub-GeV beam for Water Cherenkov

0.75MW JHF 50GeV-PS

Off-Axis beam Super-Kamiokande

5

~1GeV beamKamioka

J-PARC(Tokai)

0.75MW 50 GeV PS

( conventional beam)

Super-K: 22.5 kt

JHF 0.75MW + Super-Kamiokande

Plan to start in 2007

(hep-ex/0106019)

4MW 50 GeV PS

Hyper-K: 1000 kt

Future Super-JHF 4MW + Hyper-K(~1Mt) ~ JHF+SK 200

JHF-Kamioka Neutrino Experiment

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Collaboration

Working GroupICRR/Tokyo-KEK-Kobe-Kyoto-Tohoku-TRIUMF

(hep-ex/0106019)Y. Itow, T. Kajita, K. Kaneyuki, Y.Obayashi,

C.Saji, M. Shiozawa, Y. Totsuka (ICRR/Tokyo)

Y. Hayato, A.Ichikawa, T. Ishida, T. Ishii, T. Kobayashi,

T. Maruyama, K. Nakamura, Y. Oyama, M. Sakuda (KEK)

S. Aoki, T.Hara, A. Suzuki (Kobe)

T. Nakaya, K. Nishikawa (Kyoto)

T. Hasegawa, K. Ishihara (Tohoku)

A.Konaka (TRIUMF, CANADA)The neutrino facility construction group

was OFFICIALLY formed at KEK in 2001.LOI was submitted and people from Japan, Canada, France,

Italy, Korea, Poland, Russia, Spain, Switzerland, UK and USA signed up in 2002.

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Far detector : Super-Kamiokande（ April 1996 commissioned）

40m

41.4

m

50,000 ton water Cherenkov detector 　 (22.5 kton fiducial volume)

Optically separated INNER and OUTER detector

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J-Parc FacilityConstruction2001～ 2006 (approved)

(0.75MW)

Near detectors (280m,2km)

beam-line budget request submitted

JHF NuMI

(FNAL)

K2K

E(GeV) 50 120 12

Int.(1012ppp)

330 40 6

Rate(Hz) 0.275 0.53 0.45

Power(MW)

0.75 0.41 0.0052

To SK

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Neutrino beamlineTransport line(Super-cond. Mag.)

Target station

Decay volume130m

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OA3°

OA2°OA1°

Off Axis Beam

(ref.: BNL-E889 Proposal)

TargetHornsDecay Pipe

Super-K.

Quasi Monochromatic Beamx2~3 intense than NBB

Statistics at SK (OAB2deg,1yr,22.5kt)

~4500 tot ~3000 CC e ~0.2% at peak

~102 x (K2K)

Tuned at oscillation maximum ~0.7 GeV

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Neutrino Interaction @~1 GeV& E reconstruction

CC QE ~100% efficiency for NSK

can reconstruct Ep

CC nQE ~100% efficiency for NSK

Bkg. for E measurement

NC ~40% efficiency for NSK

+ n → + p

-

p

(E, p)

+ n → + p + ’s

p’s

-

+ n → + p +

p

(E, p)

’s

cospEm

2mEmE

N

2Nrec

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Detectors

Muon monitors @ ~140m Fast (spill-by-spill) monitoring of bea

m direction/intensity First Near detector @280m

Neutrino intensity/spectrum/direction Second Near Detector @ ~2km

Almost same E spectrum as for SK Water Cherenkov can work

Far detector @ 295km Super-Kamiokande (50kt)

1.5km

295km

0.28km

Neutrino spectra at diff. dist

dominant syst. in K2K

p

140m0m 280m 2 km 295 km

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Possible design of Near Detector at 2km

14(sin22)~0.01 (m2) ~<1×10-4

Measurement of sin2 2θ23 , m223

disappearance

True m232 (eV2)m2

sin22

FC, 1-ring, -like events

Sys. error 10% for near/far

4% energy scale

20% non-QE B.G.

OAB-3o

(m

232 ) OAB-2o

(si

n2 2 )

MeV

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→ confirmation or search for sterile neutrino w/ NC interaction

NC 0 interaction ( + N → 　 + N + 0) e CC + NC(~0.5CC) ~0 (sin22e~0)

CC + NC(~0.5CC) ~0 (maximum oscillation) NC

#0 is sensitive to flux. Limit on s (f(s)~0.1)

OAB

s

=390±44#0 +

#e-

like

m232

3.510-3

CC

NC

100MeV<Evis<1500 MeV.

#ring<3 & e-like

No decay-e

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e appearance in JHF-Kamioka

e0

Back ground for e appearance search• Intrinsic e component in initial beam• Merged 0 ring from interactions

Requirement 10% uncertainty for BG estimation

The 1kt 0 data will be studied for exercise

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0 cut after 1-ring e-like selection

reduce coherent 0

1-ring/2-ring

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sin2213 from e appearance

sin2213

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

SignalSignal + BG e e total

0.1 12.0 10.7 1.7 0.5 24.9 114.6 139.5

0.01 12.0 10.7 1.7 0.5 24.9 11.5 36.4

sin2213

m2

Off axis 2 deg, 5 years

Off axis 2 deg, 5 yearsat

Sin2213>0.006 C

HO

OZ

exc

lud

ed

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Key Issues

Extremely severe radiation environment Human exposure at maintenance Damage to instruments

Beam scraper, radiation resident magnets, abort system Large heat load in a short time

cooling scheme, shock wave, quenching Target, Horns, Target station, decay volume, beam dump

Reduction of Systematic errors

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Target

C230 C43

900mmL 30mm,

300mm~z0,rC230~ @

surfaceC70~ @

beam direction

r=0mm,z=300mm

r=1.5mm,z=300mmC70

C230

4 8 3212 (Sec.)

Time Evolution

Only graphite (or Be) can withstand heat load.

Cooling test is on going.

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Decay Volume

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.

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空隙（サービスエリア）

Strategy to change peak energy

Dipole magnet

gap 1m×1m×1m

One method is changing the beam axis.

The other…. OAB+Bending Magnet

Target station side view

OAB2o

OAB3o

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OAB vs OAB+Bending

No need to access target and horns.

Easy to change the peak energy

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Schedule & Summary –JHF-Kamioka-

JHF-Kamioka neutrino experiment (2007~) JHF 0.75MW 50GeV-PS+Off Axis beam+Super-K Narrow band beam at oscillation maximum (~ 1GeV) e appearance, discovery of 13 (sin 2213>0.006,90%CL) Budget request submitted, R&D started

Possible upgrade in future 4MW Super-JHF + Hyper-K ( 1Mt water Cherenkov) CP violation in lepton sector

2002 2004 2006 2008 2010

MINOS 2yr

OPERA 5yr

SK rebuild SK-half SK-full

JHF- construction physics run (OAB)