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日本物理学会@新潟大 2000. Sep. 22. スーパーカミオカンデ1140日の 大気ニュートリノ観測. n m → n t 2 世代解析 n m -n t -n e 3世代解析 n n ratio の測定. 大林 由尚 (東京大学宇宙線研究所) 他 Super-Kamiokande Collaboration. Event Categories. Fully Contained (FC) n m CC, n e CC, NC ~1GeV Partially Contained (PC) n m CC - PowerPoint PPT Presentation
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→ 2世代解析
e 3世代解析
ratio の測定
スーパーカミオカンデ1140日の大気ニュートリノ観測
スーパーカミオカンデ1140日の大気ニュートリノ観測
大林 由尚 (東京大学宇宙線研究所)
他 Super-Kamiokande Collaboration
日本物理学会@新潟大2000. Sep. 22
Event CategoriesFully Contained (FC) CC, e CC, NC <E>~1GeV
Partially Contained (PC) CC <E>~10GeV
Upward Going Muon (Up) CC
<E>~10GeV (Stop ~100GeV (Through
Observed Events (SK 1140day)
Sub-GeV (Evis<1.33GeV) Multi-GeV (Evis>1.33GeV)
FC DATA MC
single ring 5017 6023.5e-like 2531 2402.6-like 2486 3620.9
multi ring 1885 2321.5TOTAL 6902 8345.0
FC DATA MC
single ring 1078 1294.1e-like 576 555.4-like 502 738.7
multi ring 1198 1470.1TOTAL 2276 2764.2PC 665 945.1
051.0019.0018.0
652.0)μ/e(
)μ/e(
MC
DATA 079.0035.0033.0
668.0)μ/e(
)μ/e(
MC
DATA
Zenith Angle
P(osc)= sin22 sin2(1.27m2L/E)U/D(Multi-GeV FC+PC)=
0.54±0.04±0.01
●DATA ーMC(w/o osc.) ーMC(w/ osc.)
2 Flavor Oscillation Analysis (-)
Oscillation Analysis by FC + PC + UpmuBest Fit: 2min=135.4/152d.o.f @ sin22=1.00
m2=3.2x10-3eV2
Assuming null osc.: 2min=316.2/154d.o.fAllowed region @90%C.L.:
0.88<sin22 1.5x10-3<m2<5x10-3
(eV2)
3 Flavor Oscillation Analysis (--e)
Approximation: m2
23>> m212
m223= m2
atm>10-3eV2
m212= m2
sol<10-4eV2
m223 ~m2
13 ≡m2
Osc. Probability:Parameters:(sin213,sin223,m2)Matter effects
considered as 5 step density function
)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
( )m2
2
m12
m32
m2atm
m2sol
Data Set: FC + PC Best Fit: ()
sin213=0.019,
sin223=0.55,
m2=2.5x10-3eV2
sin213<0.34 @90%CL
Consistent with pure maximal →()
Consistent with CHOOZ
3 Flavor Analysis Result
Measurement of - ratio
Motivation: A test of the atm flux prediction
In the case of + N → - X :
- can be captured by nucleus
# decay electron ↓ (- life → short)
Data & MC are consistent within 1
74.0)(
(syst.)06.0(stat)07.066.0)/(
MCr
r
Summary
Atmospheric Neutrino @ Super-Kamiokande Livetime: 1140days
2 flavor oscillation analysis: (@90%C.L.) Mixing angle: sin22>0.88, Mass difference: m2=1.5~5x10-3eV2
3 flavor analysis: sin213<0.34 (@90%C.L.) consistent with pure →, CHOOZ
– ratio: Data & MC are consistent within 1
Transparencies for the Back Pocket
Atmospheric Neutrino
Flavor ratio
Production
Super-Kamiokande50.0kt Pure Water22.5kt Fid.Vol.1000m UnderGround(2700m.w.e.)
11146 PMTs for ID1885 PMTs for ODOperation started in Apr. 1996
Oscillation Analysiswith 3D Flux Calculation
Oscillation Analysis by FC + PC + UpmuBest Fit: 2min=147.8/152d.o.f
@ sin22=1.00 m2=3.5x10-3eV2
Incl. Unphys. Region: 2min=146.7/152d.o.f
@ sin22=1.05 m2=3.5x10-3eV2
→sterile oscillation is disfavored at 99% C.L. or sterile?
NC enrich #ring>1 e-like Evis>400MeV
High E PC Evis>5GeV
Up thru