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(I=0ÅjÉRÉA
核子
通常の核
É©ó±éq
(I=0ÅjÉRÉA
ハイパー核
Magnetic Moments of Hypernuclear states
Ultimate goal of my hypernuclear experiments
K. Nakai (IIAS)
Motivated by Akito Arima
τ= 2.6 x 10-10 sec μ 〜 μ(Λ) = - 0.613 nm
B = 20kG ⇨ ωτ = 0.03 rad = 1.7 ゜
5ΛHe
Stimulated by Gene SprouseAtomic Hyperfine Field
Bhf(H:2S1/2) = 334 kG
Bhf(5ΛHe+) = 23 x 334 kG = 2,670 kG
⇨ ωτ = 40.8 rad = 234 ゜
Can’t you measure hypernuclear magnetic moments ?
In a TEMPURA restaurant at Ikebukuro.
1994 Internationa Symposium at Riken in honor of Akito Arima
“Frontiers of Nuclear Structure Physics”5
ΛHe
F
I
J
H cosωt1
Rotating FrameLaboratory Frame
ν0I
JF
Hyperfine Frequency
ν0 (5ΛHe+) = 23 x 1,420 MHz = 2,500 MHz
Resonance Width (natural)
⊿ ν= 1/(2πτ) = 600 MHz
(⊿ν/ν0) = 24 %RF Power
ω1τ= g FH1μB/ h ≧ π
⇨ H1 ≧ 1 kG
ω=ω0=2πν0F
I
J
5ΛHe
F
I
J
Target technology Li vapor in 2.5-GHz cavity Thin cavity-window for emitted particles
6Li + X → 5ΛHe + p + K+ + X’
( p + p → Λ+ p + K+ )
GSI, 2-GeV/N 6Li-ion beam
π+ + 6Li → 6ΛLi + K+
└→ 5ΛHe + pKishimoto et al.
J-PARC: 3-GeV Ring
K ー + 6Li → 6ΛLi + π ー
└→ 5ΛHe + p
J-PARC: 50-GeV Ring
Production of the 5ΛHe Generation of the 5
ΛHe+
Slowing down of the GeV 5ΛHe+ +
XX
Well studied by Kishimoto et al.
Larger (K,π)cross section
Earlier start-upPulsed πbeam
Sufficient time for preparation
?
?
◎
○
○
?
Electron sticking in a ring
5ΛHe+
Challenge !
Challenge !
μ(Λ) = ー 0.613 ± 0.009
μ(ΛHe) = ? ? ? ± 0.06(?)5
Theoretical (1) Saito,-Oka-Suzuki, Nucl. Phys. A625(1967) p.95 - 9% (2) Nemura-Akaishi-Suzuki, PRL89(2002)142504 (3) Toki
Experiental Spin-Dependent Λ N Interactions (Following arguement )
Predictions ???
Spin-Dependent Λ N Interactions
1979 Pirner1982 Pirner and Povh
CentralNN
CentralN VV
3
2=Λ ( Central force )
0≈ΛLSNV ( L-S force )
ΛN interaction
Hypernuclear Exp.
1978 Heidelberg-Saclay Coll. at CERN
0≈ΛLSNV
uds
0
udu
2
1Λ
N
LSNN
LSN VV ≥Σ
1988 YazakiLS
ΣNVLS
N NV <
Quark cluster model
Confirmed byKEK and BNLExperiments.
∞∞
∞∞
Gluon and quark combined exchange
SCITIC
3“Φx3” NAI
60Co Can you see the scintillation light ?
Eye needs 10 photons to recognbize
6mmΦ Iris
30 cm
20ev/photon
SCIntillation Track Image Camera
p → KΣProduction)
Σp → Σp Scattering)
n → KΛProduction)
Λp → Λp Scattering)
Analyzing PowerΛpScattering
PΛ=900MeV/cfss2FSS
-0.75±0.45125 - 150
0.00±0.27100 – 125
0.42±0.2375 – 100
0.96±0.2050 – 75
0.75±0.3225 – 50
Analyzing PowerΣCM (degree)
0.00±0.35105 – 135
-0.14±0.1975 – 105
-0.18±0.3145 – 75
-0.08±0.3015 – 45
Analyzing PowerΛCM (degree)
81evnets 67evnets
ΣpScattering
PΣ=900MeV/c
fss2FSS
Kyoto Model
Kyoto Model
∞∞
∞∞
Gluon and quark combined exchange
∞∞
∞∞Χ
No s-quark vs. u,d-quark interaction
uds
Λ-spin behaves like a spectator