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Yoshihisa OBAYASHI, Oct. 2000 @Seoul Neutrino Oscillation Experiment between JHF – Super-Kamiokande Yoshihisa OBAYASHI (Kamioka Observatory, ICRR)

Neutrino Oscillation Experiment between JHF – Super-Kamiokande

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Neutrino Oscillation Experiment between JHF – Super-Kamiokande. Yoshihisa OBAYASHI (Kamioka Observatory, ICRR). JHF Neutrino Working Group. Y. Itow, Y. Obayashi , Y. Totsuka (ICRR) Y. Hayato, H. Ishino, T. Kobayashi, K. Nakamura, M. Sakuda (KEK) T. Hara (Kobe) - PowerPoint PPT Presentation

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Page 1: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Neutrino Oscillation Experiment

between JHF – Super-Kamiokande

Neutrino Oscillation Experiment

between JHF – Super-Kamiokande

Yoshihisa OBAYASHI (Kamioka Observatory,

ICRR)

Page 2: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

JHF Neutrino Working GroupJHF Neutrino Working Group

Y. Itow, Y. Obayashi, Y. Totsuka (ICRR)Y. Hayato, H. Ishino, T. Kobayashi,

K. Nakamura, M. Sakuda (KEK)T. Hara (Kobe)

T. Nakaya, K. Nishikawa (Kyoto)T. Hasegawa, K. Ishihara, A. Suzuki (Tohoku)

A. Konaka (TRIUMF)

http://neutrino.kek.jp/jhfnu

Page 3: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Overview of JHF – SKOverview of JHF – SK

→x disappearance:Precise measurement of

oscillation parameters:

(m232)~ 2x10-4eV2,

(sin22x)~ 1%

→e appearance:Explore down to

sin22e ~ 5x10-3

(sin2213 ~ 1x10-2)

Oscillation Max @ E=0.5~1.2GeV

P=sin22 ・ sin2(1.27m232L/E)

m232=2~5x10-3eV2, L=295km

Page 4: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

JHF (Japan Hadrons Facility)JHF (Japan Hadrons Facility)

JAERI @ Tokai-mura

600MeV Linac

3GeV PS

50GeV PS

N

Front Detector(s)

Neutrino Beam Line

To Super-Kamiokande

Construction:2001 ~ 2006

J H F MINOS K 2 K

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

1021p.o.t./1year(130day)

Page 5: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Far DetectorFar Detector

Super-Kamiokande @ KamiokaOperation Start: 1996295 km from JAERI50.0kt Pure Water in the tank22.5kt Fiducial Volume as a neutrino targetEnergy measurement by total amount of Cherenkov lighte- separation is performed by ring pattern likelihood

Page 6: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Neutrino Beam at JHF Neutrino Beam at JHF

Three Possible options:

Wide Band Beam (WBB)2 horns, almost same as K2K

Narrow Band Beam (NBB)Horn(s) + Bending

Off Axis BeamAnother option of NBB

Present Strategy:First 1(~2) year:

High Statistics Run with WBBPin down m2

Next 5 years:Precise Analysis with (one of) NBBMeasurement of 23,13

Page 7: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Wide Band BeamWide Band Beam

High Intensity Wide sensitivity in m2

Established technique Backgrounds from HE tail Spectra diff. btw near&far

Systematic error

Needs Heavy shieldingdecay pipe must be short

~ 4200 int./22.5kt/yr(e:0.8%)

Page 8: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Narrow Band BeamNarrow Band Beam

Less systematic error Less BG from HE tail Easy to tune E Less shielding Low intensity

~ 830 int./22.5kt/yr

(e:0.3%@peak)

Page 9: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Off Axis Beam: Another option of NBBOff Axis Beam: Another option of NBB

WBB with intentionally misaligned from detector axis

Quasi Monochromatic Beam

E

E

20

10

Page 10: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Off Axis BeamOff Axis Beam

More intense than NBB More HE tail than NBB Hard to tune E Needs heavy shielding Not established technique

Beam monitorNear/Far ratio, …

~ 2200 int./22.5kt/yr

(e:0.2%@peak)

Page 11: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Physics SensitivityPhysics Sensitivity

Page 12: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Disappearance Disappearance

Ratio after BG subtraction:

Fit with 1-sin22・ sin2(1.27m2L/E)

Page 13: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Disappearance Disappearance

Possible systematic errors:inelastic cross section: 20%Spectrum @FD: 4%・ ESpectrum diff.(Near/Far): 10%Energy measurement: 3%

(sin2223)~0.01 in 5 years

(m23) ~ 2x10-4eV2

Page 14: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

→ e Appearance → e Appearance

Three flavor oscillation framework:

m212 <<m2

23 ~m2

13≡m2

m223= m2

atm>10-3eV2

m212= m2

sol<10-4eV2

Oscillation Probability P :

Present limit: sin22e < 5x10-2

sin22e= sin22 ・ sin2sin22 <0.1(CHOOZ)

sin2 ~ 0.5 (Atmospheric )

Goal: sin22e ~ 5x10-3

)27.1

(sincos2sin)(

)27.1

(sin2sincos)(

)27.1

(sinsin2sin)(

22

232

132

22

232

134

22

232

132

E

LmP

E

LmP

E

LmP

e

e

m22

m12

m32

m2atm

m2sol

Page 15: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Signal & BackgroundsSignal & Backgrounds

Signal: e C.C. interaction

BG 1: C.C. interaction

Single fuzzy ringCherenkov angle ~ 42deg.

e

e+- shower

Sharp ring edgeCherenkov angle < 42deg.

easy to reject

Page 16: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Backgrounds (continued)Backgrounds (continued)

BG 2: N.C. 0 production

→ 2 showers

2 fuzzy rings →→ hard to separateNot reproduce E

need effort to reject

Page 17: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

e Selection by SK Official Cutse Selection by SK Official Cuts

S/N ~ 1/3 (@sin22e=0.05)Main Background come from 0

(w/0) e

Fid. Vol. 3651 795 53.31R e-like 92 68 29.5

reduct.rate 2.5% 8.6% 55.3%

sin22e=0.05,

m2=3x10-3eV2

Page 18: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

0 rejection0 rejection

Force to find 2nd ring

Cut with follow quantities:

Shower direction w.r.t. (cose)

Energy fraction of second R(2)=E(2)/(E(1)+E(2))

Pattern likelihood difference

Invariant mass of 2

Page 19: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

PRELIMINARY

0 cut efficiency0 cut efficiency

WIDE e

Fid. Vol. 3651 53.3

1R e-like 92(2.5%) 29.5(55.3%)

0 cut 4.0(0.1%) 9.8(18.4%)

2deg. e

Fid. Vol. 1801 45.5

1R e-like 37.4(2.1%) 32.1(70.5%)

0 cut 3.8(0.2%) 24.3(53.4%)

LE2 e

Fid. Vol. 740 23.0

1R e-like 13.2(1.8%) 16.2(70.4%)

0 cut 1.8(0.2%) 11.6(50.4%)

WBB 1year

NBB 1year

Off Axis 1year

sin22e=0.05,

m2=3x10-3eV2

Page 20: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

→ e Oscillation Sensitivity → e Oscillation Sensitivity

sin22e~5(3)x10-3 @90%CLby 5year run of NBB (off axis beam)

PRELIMINARY

10% systematic inBG rate is considered

Page 21: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

→ e Oscillation Sensitivity → e Oscillation Sensitivity

PRELIMINARY

10% systematic inBG rate is considered

Page 22: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Comparison to MINOSComparison to MINOS

JHF neutrino is more sensitive especially in Atmospheric m2 region

MINOSPh2he,me,le2yr exposure(hep-ph0005012)

Page 23: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

→ ? sterile?→ ? sterile?

NC 0 production:+ N → + N + 0

In the case of → sterile oscillation,

Number of 0 also decrease

⇔ sterile discrimination

CC NC

Yes Yes

Few Yes

sterile No No

Page 24: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

SummarySummary

JHF neutrino experimentExpected to start in 2006

Far Detector: Super-KBy 5 years of run:

disappearance search(m2

23) ~ 2x10-4eV2

(sin2223) ~ 1%

e appearance search

sin2213 ~ 10-2 @90%CL

⇔ or ⇔sterile

Can be tested

Page 25: Neutrino Oscillation Experiment  between JHF – Super-Kamiokande

Yoshihisa OBAYASHI, Oct. 2000 @Seoul

Test of CP Violation Test of CP Violation

If sin2213 ~ 0.01, sin2212,m212~LMA

1MW(2deg. off axis) → SK :2 → e / year Too few to see CP

4MW → Mton :300 → e / year

100 → e / year

1year + 3year 600 total events with asym: 150xsin

=30deg.(3), 12deg.(90% CL)