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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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Yoshihisa OBAYASHI, Oct. 2000 @Seoul
Neutrino Oscillation Experiment
between JHF – Super-Kamiokande
Neutrino Oscillation Experiment
between JHF – Super-Kamiokande
Yoshihisa OBAYASHI (Kamioka Observatory,
ICRR)
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
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
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)
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
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
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%)
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)
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
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)
Yoshihisa OBAYASHI, Oct. 2000 @Seoul
Physics SensitivityPhysics Sensitivity
Yoshihisa OBAYASHI, Oct. 2000 @Seoul
Disappearance Disappearance
Ratio after BG subtraction:
Fit with 1-sin22・ sin2(1.27m2L/E)
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
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
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
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
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
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
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
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
Yoshihisa OBAYASHI, Oct. 2000 @Seoul
→ e Oscillation Sensitivity → e Oscillation Sensitivity
PRELIMINARY
10% systematic inBG rate is considered
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)
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
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
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)