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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
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。
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
2
4
6
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10
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14
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
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.
24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
νe−νX 間のニュートリノ振動
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
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。
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)
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
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.
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 −+
=
24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Jefferson Lab Map
Beam Line Beam Line →→
Hall C Hall C ↑↑
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
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)
24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Target (Liq.H2, Liq.D2, Carbon, Fe, Al)
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%
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
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.
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
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
24 February 2005 M.Sakuda Neutrino-Nucleus Interactions
Theoretical Calculation in Preparation
Fermi-Gas Spectral Function
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
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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8
10
12
14
16
18
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
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40
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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
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。
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