作田誠(岡山大学) - osaka universitysakemi/neu/slide/sakuda.pdf2. e04-001 (c.keppel and...
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
GeV領域での電子-(H,D,C)準弾性反応, ∆(1232)生成断面積の測定
作田 誠 (岡山大学)
平成17年2月24日 @ RCNP
1. ニュートリノ実験の結果とニュートリノ原子核反応
2. JLAB E04-0013. まとめ
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
1.ニュートリノ振動の結果(2004)
νµ−ντ (2-3世代)間のニュートリノ振動(K2K/SK)Δm232 =|m22-m32|=(1.5~3.5)x10-3(eV2)θ23=45±8º
νe−νµ (1-2世代)間のニュートリノ振動(SK他)Δm122 =|m12-m22|=(8.2±0.6)x10-5(eV2) θ12=32±3º (1σの信頼度)
次の目標はνe−ντ (1-3)間のニュートリノ振動をsin22θ13 の値にして0.01 (1%)で測定することである。ニュートリノ物理は素粒子・宇宙物理の重要課題として、次の10年にはさらなる発展が期待される。
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
νµ−ντ (2-3世代)間のニュートリノ振動
SK実験により発見された大気ニュートリノ振動はK2K 実験により2004年に99.99% の確度で確認された。
Eνrec0
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16
18
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Entries 56
[GeV]
even
ts/0
.2[G
eV]
data
Oscillation
No osc.
SK観測による大気ニュートリノデータ K2K
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
νµ-ντ oscillations estimatedby SK and K2K at 90%CL
10-4
10-3
10-2
10-1
0 0.2 0.4 0.6 0.8 1sin22θ
∆m2
(eV2
) K2K
SK-I All SK-I L/E
K2K result is consistent with SK-I results.
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
νe−νX 間のニュートリノ振動
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
次の目標: νe−ντ or νe−νµ oscillation at 1% or less by T2K,NOvA and Reactors in ~2009
KASKA 90% C.L. Sensitivity (L=1.8km, 1% error, 3yrs)
10-1
10-2
10-3
10-4
sin2 2
m2
(e
V2)
10-3 10-2 10-1 1
ChoozExcluded
T2KOAB 2degree
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
GeV領域のニュートリノ原子核反応
1. ニュートリノ振動解析のためにはニュートリノ原子核反応(微分)断面積が必要である。
Y(Eν)=(Neutrino flux) · σ(Eν) · (Number of target nucleons) .
もし、sin22θ13~0.01-0.001 を狙うなら断面積も数%程度の精度で知りたい。
2. GeV領域の電子・ニュートリノ原子核反応計算を100 MeV から10 GeV領域で確立したい。Supernovaにも関係する。
3. Weak nucleon form factor も良く分かっていない。
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
MiniBOONE と K2K の Q2 分布
MiniBOONE QE sample K2K Inelastic sample
SciFi SciBar
•Nuclear Effect or unknown cross sections (QE,1π, coherent)長谷川 の講演
We need better measurement of σ(C,O)/σ(H) for qe, ∆ using electron beams. E04-001 (JLAB)
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Pauli Bloching effect
Quasi-elastic
∆ production
W/o Pauli effect
W/ Pauli effect
10-15% suppressionAt low Q2
Total 3% reduction
Eν=1.3 GeV,kF=220 MeV/c
ν µ−
Pp
Pp
πqW∆
ν µ−
np
Pp
q
If P
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
2. E04-001 (C.Keppel and A.Bodek et al)
The original proposal E04-001 is to measure the longitudinal-transverse structure functions F2 and R=σL/σT from the nuclear target in the resonance region.We (M.Sakuda et al) requested a measurement of elastic and ∆ cross sections with H,D,C targets in the forward region last November and it was approved in December, 2004. Data taking took place in January, 2005.
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
( )2
sin'4 222 θEEQq ==−
[ ]),(),('
22 QxQxdEd
dLT εσσ
σ+Γ=
Ω
)1(2)('
2
22
επα
−−
=ΓEMQ
MWE
P
P
1
22
2
2tan121
−
⎥⎦
⎤⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛++=
θνεQ
[ ]),(),(2)(
4'
22122
2
QxFQxxFMWxdEd
dL
P
εαπσ +−
Γ=Ω
),(2),(41
),( 212
22
222 QxxFQxF
QxM
QxF PL −+
=
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Jefferson Lab Map
Beam Line Beam Line →→
Hall C Hall C ↑↑
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
The electron accelerator at JLAB
Ee=1-6 GeVAccelerated by two linacs in a racetrack design.
A B C
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Hall-C 内部↓
Detector’s outline→High Momentum Spectrometer (HMS)
←Target
↑electron beam
Short OrbitSpectrometer (SOS)
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Target (Liq.H2, Liq.D2, Carbon, Fe, Al)
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
High Momentum Spectrometer (HMS)
Θ=10.6-90.0 degPmax=7GeV∆p/p=20%dp/p=0.1%
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Typical spectrum for the HMS Ĉerenkov counter
Typical spectrum for the HMS shower counter
Electron Identification (Gas Cherenkov and Lead Glass)
Pion
Electron
Electron
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Q2 -1.15 -0.966 -0.811 -0.682 -0.573 -0.481 -0.404
10.8 0.0499 C C C C C C C
13 0.0715 H2,D2 H2,D2,C,Al H2,D2,C,Al H2,D2,C,Al H2,D2,C,Al H2,D2,C,Al H2,C
16 0.1063 H2,Al D2,C,Al D2,C,Al D2,C,Al D2,C,Al D2,C,Al
19 0.1467 D2 C C C C
22 0.1918 H2,D2,C,Al D2,C,Al H2,D2,C,Al H2,D2,C,Al H2,D2,C,Al
28 0.2932 H2,C,Al C C H2 C C
45 0.6136 H2,C,Al,Fe H2,D2,C,Al,Fe H2,C,Al,Fe H2,D2,C,Al,Fe H2,D2,C,Al,Fe H2,D2,C,Al,Fe
55 0.7946 H2,D2,C,Al,Fe H2,D2,C,Al,Fe H2,D2,C,Al,Fe H2,D2,C,Al,Fe H2,D2,Al,Fe
60 0.8782 D2
70 1.029 H2,D2,C,Al,Fe H2,D2,C,Al,Fe C ,Al ,Fe
E’ (GeV)
Θ(d
eg)
Data H,D,C(e,e’) at Ee=1.2 GeVOne data point consists of 600K events. Q2=0.05-0.6 (GeV/c)2.
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
結果一例 (Semi-Online Analysis)
Target = H2e- energy (GeV) = 4.62
HMS deg = 10.6
Prelim
inary
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Typical Systematic Uncertainty
Quantity Uncertainty εσ (%)
Incident e- energy ~10-3 0.2-0.3Scattered e energy ~10-3 0.1Scattering e- angle ~1mr 0.7-0.8
Target density 0.7% 0.7Total charge ≤1% ≤1
Tracking Efficiency 0.7% 0.7Detector Efficiency 0.9% 0.9
Dead Time Correction 0.5% 0.5Radiative Correction 1.0% 1.0
Bin Centering Correction 1.7% 1.7
Acceptance Correction 0.5% 1.5Total charge 3.1
Ratio or measuredand
Simulated elastic cross section
Sources of systematic uncertaintiesin the differential cross section
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Theoretical Calculation in Preparation
Fermi-Gas Spectral Function
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Uniform Fermi-Gas and Spectral Function for Various Nuclei
Spectral Functions P(p,E) for various nuclei, eg.16O, are estimated by Benhar et al. using e-N data.P(p,E) : Probability of removing a nucleon of momentum p from ground state leaving the residual nucleus with excitation energy E.
0. 100. 200. P (MeV/c)
20.
40.
E(MeV)
Fermi momemtum
Fermi Gas model
p
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
dσ/dEe’ (e+O e+X, ω=Ebeam-Ee)
Fermi-Gas (Present) vs. Spectral FunctionFG > SF at peak 10-20%, SF can explain ‘dip region’
H.Nakamura,Seki, MS,Nucl.Phys.B(Proc.Suppl.)139,201,2005.Nieves et al., Nucl.Phys.B(Proc.Suppl.)139,195,2005.
0
2
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0 100 200 300 400 500 600
dσ
/dΩ
dω
[10
-7fm
2/M
eV]
ω [MeV]
E = 1080 MeV θ = 32 deg
SFFG
0
10
20
30
40
50
60
70
80
90
0 100 200 300 400 500 600
dσ
/dΩ
dω
[1
0-7
fm2/M
eV]
ω [MeV]
E = 700 MeV θ = 32 deg
SFFGFG
SF
QE
∆
FG
SF
Dip
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
まとめ
GeV領域の電子・ニュートリノ原子核反応を総合的に理解したい。
理論計算は、準弾性反応・∆生成に関しては準備が整った。
JLABで1.2GeVの電子ーH, D, C 反応を測定した。これで前方の準弾性、共鳴生成断面積は、5%以内(目標1%)でまもなく解析できると期待される。
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24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
9月26-30日(岡山大学)-日本学術振興会日伊共同セミナー-
The 4th Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region