1 the jhf-kamioka neutrino experiment 1.introduction 2.overview of the experiment 3.physics...

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The JHF-Kamioka Neutrino experimentThe JHF-Kamioka Neutrino experiment

1. Introduction

2. Overview of the experiment

3. Physics sensitivity in Phase-I

4. Physics sensitivity in Phase-II

5. Summary and Conclusion

Tsuyoshi NAKAYA (Kyoto U.)for JHF-SK working group

Jan 16, 2002@IIAS

JHF is an tentative name, and will be renamed soon.

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JHF-SK Neutrino Working GroupICRR/Tokyo-KEK-Kobe-Kyoto-Tohoku-TRIUMF

15,5

Y. Itow, T. Kajita, K. Kaneyuki, M. Shiozawa, Y. Totsuka (ICRR/Tokyo)

Y. Hayato, T. Ishida, T. Ishii, T. Kobayashi, T. Maruyama,

K. Nakamura, Y. Obayashi, M. Sakuda (KEK)

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

A. Ichikawa, T. Nakaya, K. Nishikawa (Kyoto)

T. Hasegawa, K. Ishihara, A. Suzuki (Tohoku)

A.Konaka (TRIUMF, CANADA)

In addition to the above user group, the neutrino facility construction group is OFFICIALLY formed at KEK.

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1.Introduction

~1GeV beamKamiokaJAERI

(Tokaimura)

0.77MW 50 GeV PS

( conventional beam)

Super-K: 22.5 kt

4MW 50 GeV PS

Hyper-K: 1000 kt

Phase-I (0.77MW + Super-K)Phase-II (4MW+Hyper-K) ~ Phase-I 200

The experiment will start in 2007.The experiment will start in 2007.

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Lepton Sector Mixing

12, 23, 13

+ m2

12, m223

MNS (Maki-Nakagawa-Sakata) matrix

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oscillation

GeVE

kmLeVmP

PGeVE

kmLeVmP

e

e

22232

132

132

22232

134

232

27.1sinsin2sin)(

)(27.1

sincos2sin1)(

at 23~/4 and 13~0

GeVE

kmLeVmP

PGeVE

kmLeVmP

ee

e

222322

222322

27.1sin2sin)(

)(27.1

sin2sin1)(

2

31322

2322 22sin

2

12sin,2sin2sin ee U

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Targets of JHF-SK experiment

• Confirmation of

• Discovery of eat m2atm.

• Precise measurement of neutrino oscillation. (observation of oscillation peak)

• CP violation in neutrino oscillation.

• Confirm or Reject LSND anomaly.

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2. Overview of the experiment

Construction2001～ 2006 (approved)

JHF MINOS K2K

E(GeV) 50 120 12

Int.(1012ppp)

330 40 6

Rate(Hz) 0.29 0.53 0.45

Power(MW)

0.77 0.41 0.0052

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

Super Conductingmagnet for beam line

Near detectors@280m and@~2km

1021POT(130day)≡ “1 year”

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beam at JHF

• Principle– Intense Narrow Band Beam

– Beam energy is tuned to be at the oscillation maximum.

• High sensitivity

• Less background

– ~1 GeV beam energy for Quasi-elastic interaction.

E(reconstruct) – E (True) (MeV)

m2=1.6~4x10-3eV2

E=0.4~1.0GeV

=80MeV + n → + p

p

(E , p)

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Off Axis Beam

WBB w/ intentionally misaligned beam line from det. axis

(ref.: BNL-E889 Proposal)

Target Horns Decay Pipe

Far Det.

～ 3100 int./22.5kt/yr w/ 80m long decay volumee: 1.0% (0.2% @ peak)

Decay Kinematics

~2°

E(Present design; 130m 40% more)

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detectors at JHF

1 Mton (fiducial) volume: Total Length 400m (8 Compartments)

Super-K

40m

Total Length 400m (8 Compartments)

Phase-I: Suker-K22.5kt (50kt)

Phase-II: Hyper-K1Mton (fiducial) volume:

We are investigating the possible site at Kamioka.

70m

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Near Detectors ( Detectors at two locations are essential.)

@280m (1~10 events/spill/100ton) Fine Grained w/ magnet.– Measure direction and spectrum.– Measure wrong sign component (see CP section).– Will be used for interaction study with NBB.– Non-oscillation physics.

@~2km (0.1 events/spill/100ton) Water Cherenkov + Fine Grained– Measure spectrum and e background since they are s

ame as those at Kamioka.– Test LSND anomaly if Mini-Boone failed to test it or di

scovered the new physics.

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Far/Near Spectrum Ratio

spectrum

0.28km

1.5km

295km

At >1.5km, the source is treated as a point source

Low Ep High Ep

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3. Physics sensitivity in Phase-I (w/ Super-K)

5years (51021POT) running precise measurement of m223 and 13

(m223 )e (13 , open window for CP study) w/ NC interactions. (confirmatio

n)stringent limit on the non-oscillation scenario a

nd the existence of s.Sensitivity (goal):sin22sin22CLm2eV2

atsin22m2eV2

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→ confirmation 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

m2323.510-3

CC

NC

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e appearance

C.C. N.C. Beam e Osc’d e

Generated 10713.6 4080.3 292.1 301.6

1ring e-like 14.3 247.1 68.4 203.7

red. eff. 0.1% 6.1% 23.4% 67.5%

e/0 sep. 3.5 23.0 21.9 152.2

red.eff. 0.03% 0.6% 7.5% 50.4%

.4<E<1.2 1.8 9.3 11.1 123.2

red.eff. 0.02% 0.2% 3.8% 40.8%

e0

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e appearanceBackground rejection against NC 0 is improved.

sin22e=0.05 (sin22e 0.5sin2213)

3 ×10-3

×20 improvement

CHOOZ

sin22e

m2

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disappearance

1ring FC -like

Reconstructed E (MeV)

Oscillation with m2=3×10-3

sin22=1.0

No oscillation

Non-QE

(linear)

(log)

m2=3×10-3

sin22=1.0

~3%

Ratio after BG subtraction

m2

sin22

sin22m

2eV2

Fit with 1-sin22・ sin2(1.27m2L/E)

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4. Physics sensitivity in Phase-II (w/ Hyper-K)

2 years (101021POT) for and 6 years (301021POT) for running

Search for CP violation in oscillation.standard: e vs e

non-standard: vs w/ NC Search for e

Search for proton decays.

Sensitivity (goal):sin22CLdiscovery

atm122eV2m23

2eV2

proton•B(pe0, K) > 1035 years

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CP violation in oscillation

sinsin

2sin

4)()(

)()(

13

122

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E

Lm

PP

PPA

ee

eeCP

L=295km : small matter effectE~1 GeV : large CP asymmetry

Acp

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flux for CP violation search.

-15%@peak

1021POT/yr(1st phase)

Sign flip by change of horn plarity

Flux CC interaction

Wrong sign BG

cross sectiondifference

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CP Violation Study• Compare e with e

N(e-)

N(e+)

NO CP violationw/o matter effect.

m122

eV2m23

2eV2

sin22

02.02000~2000~

2000~2000~

)()(

)()(

eNeN

eNeN

Asymmetry discovery

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5. Summary and Conclusion

• The experiment is expected to start in 2007 at the same time of the completion of JHF 50 GeV PS.– The experiment is not approved yet, and we need your

STRONG support to put the experiment on track.

• The features of the experiment are:– MW class 50 GeV proton accelerator (0.77MW 4MW)

– ~1GeV Narrow band neutrino beam at the oscillation maximum (L=295km).

– Gigantic Water Cherenkov detectors with/ neutrino energy reconstruction by quasi-elastic interaction. (22.5kton 1000kton)

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Physics Reach (see hep-ex/0106019)

• Phase-I (0.77MW + 22.5kt): NC interaction:Establish and limit on s

: sin22e : sin22CL : m2eV2

atsin22m2eV2• Phase-II (4MW + 1000kt):

e : sin22CLe vs e : discovery

atm122eV2m23

2eV2proton•B(pe0, K) > 1035 years