短寿命核ビーム物理グループの紹介lambda.phys.tohoku.ac.jp/slnb/guidance4.pdf短寿命(1ms~数秒)の原子核ビームの生成 宇宙核物理・原子核構造の研究
200MeV-GeV 領域での電子原子核反応実験sakemi/snWS/slide/sakuda.pdf200MeV-GeV...
Transcript of 200MeV-GeV 領域での電子原子核反応実験sakemi/snWS/slide/sakuda.pdf200MeV-GeV...
2 March, 2007 M.Sakuda RCNP Workshop
200MeV-GeV 領域での電子原子核反応実験
作田 誠 (岡大理)
2007年3月2日@大阪大学核物理センター
Outline1. 電子原子核反応とニュートリノ原子核反応2. Quasi-elastic 3. Pion production 4. まとめ
2 March, 2007 M.Sakuda RCNP Workshop
Neutrino Cross Section (by Lipari ‘90)
For Eν< 2 GeV, Quasi-Elastic interaction and 1πproduction dominate the cross section.
QE
1π
Total
1. 2.(GeV)
2 March, 2007 M.Sakuda RCNP Workshop
Quasi-elastic and Resonanc cross sections (Fermi Gas Model) in the GeV region and the nuclear effect
Quasi-elastic
∆ production
W/o Pauli effect
W/ Pauli effect
Eν=1.3 GeV,kF=220 MeV/c
ν µ−
Pp
Pp
πqW∆
ν µ−
Pp
qnp
If P <kF , suppressed.
Nuclear effects are large in the low Q2 region, where the cross section is large.
dσ/dQ2
dσ/dQ2 0.5 1.0
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1. 電子原子核反応とニュートリノ原子核反応
µ
p
ν
p
e e q2q2
電子原子核反応 ニュートリノ原子核反応
•e-N: Vector current, ν-N: V-A current•Ee 正確、Eν 不正確、 電子散乱の方が精密に実験できる。•原子核効果(Pauli blocking, Final State Interaction)も、電子散乱でより正確に評価できる。•Axial current の情報は、ニュートリノ実験でのみ。
2 March, 2007 M.Sakuda RCNP Workshop
1.電子原子核反応とニュートリノ原子核反応
Electromagnetic current (Jaem) and weak hadronic
charged current (JaCC=Va
1+i2–Aa1+i2)
[ ] ),()()()'()(||)'(
),()(2
)()'()(||)'(
),()(2
)()'()(||)'(
225
21
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puQFqQFpupnApp
puQFqMiQFpupnVpp
puQFqMiQFpupNJpN
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NNem
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βαβαα
βαβαα
γγ
σγ
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+>=<
⎥⎦⎤
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⎥⎦⎤
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QGQGQF
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withQFQFQG
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nME
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VME
NNNM
NNNE
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The electron accelerator at JLAB
Ee=1-6 GeVAccelerated by two linacs in a racetrack design.
他にもMAINZA B C
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e - N scattering formalism
( ) ( )[ ]2L
2T Qx, Qx,
dE'dd εσσσ
+Γ=Ω
σT (σL) is the Transverse (Longitudinal) virtual photon Cross Section
( )( )επ
α−
−=Γ
12'
2
22
EMQMWE
p
p
Transverse virtual photon flux
V. Tvaskis
NN
QQ22
e(E)e(E) ee’’(E(E’’))
θθ
1
22
2
2tan121
−
⎥⎦
⎤⎢⎣
⎡⎟⎟⎠
⎞⎜⎜⎝
⎛++=
θνεQ
/EE −=ν
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2.Quasi-Elastic Interaction
Quasi-Elastic is understood to 10% for E=700MeV-2000MeV (and Q2>0.2 (GeV/c)2)
(Benhar et al., PRD72,053005,2005)Two key inputs:
Spectral Function S(p,E): validated by JLAB E97-006Final state interactions: validated by JLAB E97-006
Cf. D.Rohe et al.(JLAB E97-006),PRC72,054602,2005
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Spectral Function for Various Nuclei-Tabulated by Benhar
Only 65% of the nucleons in nucleus is in Shell States. -D.Rohe @NuInt05 and (JLAB E97-006), PRC72,054602,2005
Fermi momemtum
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Validation of FSI effect: Calculated transparency compared to data
D.Rohe, O.Benhar et al(E97-006), PRC72,054602,2005
Transparency= Probability that a nucleon can escape from the nucleus without being subject to any interaction.i.e. T=1.0 = Completely transparent=No interaction
2 March, 2007 M.Sakuda RCNP Workshop
Quasi-Elastic(QE) is Good with SP+FSIBenhar et al., PRD 72, 053005 (2005)
QE ΔDIP
Energy Transfer
QE (SP&FSI, red) is good to 10% level. Calculations with Fermi-Gas (dash) and SP only (blue) are also shown. But, Pion looked bad. Next.
Diff
eren
tial C
ross
Sec
tion
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3. 1π production
Our approach to Pion ProductionHow well do we understand ep epπ: H(e,e’) ?
Calculations must agree on A=H (hydrogen).See the following Pages.
What are the new effects for A=C/O/Fe?The tail of QE is significant (SP+FSI).Meson exchange and Non-resonant pionproduction (MAID)2nd Resonance (Paschos-Lalakulich)
2 March, 2007 M.Sakuda RCNP Workshop
∆ production model Paschos,Yu,MS, PRD69(‘04)Sato-Lee, PRC67(‘03)
Pauli effect G(W,Q2 ,kF)Correct N-∆ form factor 3-4 resonancese-p data look good.
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Paschos PRD69,D74=Sato-Lee, wrt ∆(1232)
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Sato-Lee includes the non-resonant graphs.Paschos does not have it. MAID is doing something good.
2 March, 2007 M.Sakuda RCNP Workshop
∆ production and N ∆ transition form factors
)()(
)()''()()/()(
)'(
)(||)'(
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>∆<
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γγ
γγ
αµµααµµααµµα
µ
α
αµαµµααµµααµµαµ
α
ααα
・
・・
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MAID2003
D. Drechsel, S.S. Kamalov, L. Tiator (Mainz U.), Nucl. Phys. A645 (1999) 145-174A Unitary Isobar Model for Pion Photo- and Electroproduction on the NucleonResonances: P33, and higher.Non-Resonant: Born terms, ρ /ω exchange.
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2 March, 2007 M.Sakuda RCNP Workshop
1. QE (FG) + MAID (P33 only) , or Paschos P33 (FG) red2. QE(SP+FSI) , MAID (P33+non-res)SP: light blue3. Total: magenta
0
10
20
30
40
50
0 100 200 300 400 500 600
dσ/d
Ωdω
[10-7
fm2 /M
eV]
ω [MeV]
E = 880 MeV θ = 32 deg
O(e,e')FG QE+P33
SP QESP MAID
SP QE+MAID
QE Peak
Δ peakDIP
Anghinolfi et al., NPA602(’96),405.
Paschos FG (P33 only)
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Hall-C 内部↓
Detector’s outline→High Momentum Spectrometer (HMS)
←Target
↑electron beam
Short OrbitSpectrometer (SOS)
2 March, 2007 M.Sakuda RCNP Workshop
QE and ∆ with target H,D,C(e,e’) at Ee=1.2 GeVOne data point consists of 600K events. Q2=0.05-0.6 (GeV/c)2.
E’ (GeV)
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
Θ(d
eg)
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Kinematic Coverage of E04-001
Low QLow Q2 2 data for data for ν ν modelingmodeling•• Targets: H,D, C, Al Targets: H,D, C, Al
•• Uncertainties in preliminary data Uncertainties in preliminary data
estimated at ~3 estimated at ~3 -- 8% 8%
(Much larger (Much larger RCsRCs and rates)and rates)
σσTT, , σσLL
•• Targets: D, C, Al, Fe , and Targets: D, C, Al, Fe , and some H some H
•• Uncertainties in preliminary data estimated Uncertainties in preliminary data estimated at 1.6 % ptat 1.6 % pt--pt in pt in εε (2% normalization).(2% normalization).
W2 (GeV)2
Q2 (
GeV
)2
W2 (GeV)2
Q2 (
GeV
)2
超前方=原子核効果大
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結果一例 (Semi-Online Analysis)
Target = H2e- energy (GeV) = 4.62
HMS deg = 10.6
Prelim
inary
2 March, 2007 M.Sakuda RCNP Workshop
0
0.1
0.2
0.3
0.4
0.5
0.6
0 1 2 3 4
θ = 20.00o
EBeam = 2.3 GeV, Target = D
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0 1 2 3 4
θ = 30.00o
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
0 1 2 3 4
θ = 45.00o
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0 1 2 3 4
θ = 60.00o
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)0
0.1
0.2
0.3
0.4
0.5
0.6
0 1 2 3 4
θ = 20.00o
EBeam = 2.3 GeV, Target = C
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0 1 2 3 4
θ = 30.00o
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
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0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0.02
0 1 2 3 4
θ = 45.00o
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0 1 2 3 4
θ = 60.00o
W2 (GeV2)
dσ
/dΩ
/dE
/ /A (
µb/s
r/G
eV
)
Preliminary Cross Section Results (JUPITER) Tvaskis/Bradford@NuInt05
Deuterium:Deuterium: Fits to previous Fits to previous JLabJLab & SLAC & SLAC resonance region data.resonance region data.
Heavy targets:Heavy targets: fits to DIS data (Ffits to DIS data (F22 & R) + & R) + yy--scaling QE model.scaling QE model.
----- Input models for RCs, etc.
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CLAS: CEBAF Large Acceptance Spectrometer (Hall B)
2 March, 2007 M.Sakuda RCNP Workshop
CLAS Single Event Display
Charged particle angles 8o-144o
Neutral particle angles 8o-70o
Momentum resolution ~0.5% (charged)
Angular resolution ~0.5 mr (charged)
Identification of p, π+/π-, K+/K-, e+/e-, etc.
2 March, 2007 M.Sakuda RCNP Workshop
Exclusive measurements for the ν program at CLAS
Neutral and charged pions look different in ν detectors.
Eν is a critical quantity. Tune models that can be used in ν expts.
Oscillations
No oscillations
i.e., K2K result, Eν is important Paschos, Schienbein, Yu, hep-ph/0408148
ANP model calculationsK2K Collaboration, hep-ex/0212007.
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まとめ
電子原子核実験は、高統計のものがたくさんあるので、原子核効果を含めたQuasi-elastic interaction やPion production を理解するには大変有効。
Spectral Function (E,P) やFSI も電子実験データのおかげで計算が正当化された。
JLAB data で、Q2<0.2 (GeV/c)2 の解析が進行中。
超前方(原子核効果)やDIP 領域も理解が進むと思われる。
2 March, 2007 M.Sakuda RCNP Workshop
Pauli effect G(W,Q2 ,kF)Correct vector form factor 3-4 resonancesConsistency with e-pdata
Improved ∆ production model - Paschos et.al PRD69(‘04),PRD71(‘05) and Sato-Lee, PRC67(‘03)
2 March, 2007 M.Sakuda RCNP Workshop
Resonance to DIS (Bodek-Yang at NuInt01/02)
( )
).735.1/()624.0(
)(188.0
)(
)()()(
22
22
2
2
22
xQQxxwhere
xFQ
QxF
xqxxxqexF
w
w
iiii
++=
+=
+=∑
Dashed: GRV94 Red:Bodek-Yang
We will hear more details.Melnitchouk’s talk,
Phys.Rep.406,2005.
SLAC/Jlab resonance data (not used in the fit)