Measurements of Ay for the pd breakup reaction at 250MeV Yukie Maeda (CNS, Univ. of Tokyo) T....
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Transcript of Measurements of Ay for the pd breakup reaction at 250MeV Yukie Maeda (CNS, Univ. of Tokyo) T....
Measurements of Ay for the pd breakup reaction at 250MeV
Yukie Maeda (CNS, Univ. of Tokyo)T. Uesaka, T. Kawabata, K. Suda, S. Sakaguchi, Y. Sasamoto
(CNS, Univ. of Tokyo)
H. Sakai, K. Yako, M. Sasano, S. Noji (Dep. of Physics, Univ. of Tokyo)
K. Hatanaka, Y. Sakemi, A. Tamii, Y. Shimizu, Y. Tameshige, T. Matsubara,
M. Takechi (RCNP)
T. Sagara, T. Wakasa, M. Dozono, E. Ihara (Dep. of Physics, Kyushu Univ.)
K. Sekiguchi (RIKEN)
SPIN2006, October 2, 2006, Kyoto
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Introduction; Three Nucleon Force (3NF)
Study of 3NF effects
Nuclear force (2NF,3NF)input
Faddeevequation
numericalresults
experimentalresults of 3NS
TM-3NFUrbana IX-3NF
CDBonn, AV18, Nijmegen I/II/93
Cross SectionSpin Observables
Binding Energyof 3H, 3He
N+d scattering at intermediate energy N+d scattering at intermediate energy region is good probe for 3NF effects.region is good probe for 3NF effects.
135MeV/A : DCS & A135MeV/A : DCS & Ayy data are well reproduced by introducing 3NF!! data are well reproduced by introducing 3NF!!
3
N+d elastic scattering at 250MeV
p+d (K. Hatanaka et.al, PRC66(2002)044002) & n+d (Y. Maeda PhD thesis) measurements at RCNP
● pd
: NN only : NN with TM-3NF : AV18+UrbanaIX-3NF : CD-Bonn+TM’-3NF
Calculations by Prof. Kamada
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Relativistic effects
Fully relativistic calculations by Witała et al.
Non-Rel.
Rel. NN potential
Lorentz boosted potential
Approx. 1 Approx. 2
Relativistic effect is limited to the very
backward angles.
Large discrepancy indicates that we need other types of 3NF (?)
More studies of 3NF at 250 MeV are imporMore studies of 3NF at 250 MeV are important to understand this discrepancy.tant to understand this discrepancy.
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pd breakup reaction
Why are Nd breakup reactions good at this energy?
E1
E2
tot
breakupela
Cross section becomes relatively large.
J. Kuroś et al., PRC66 (2002) 024003
Elastic scattering Integration of all p
Breakup reaction Select a point on the S-curve
It is important to select good kinematical configuration to search the detail of 3NF effect.
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Analyzing powers
Around the final state interaction (FSI) configuration at 200MeVJ. Kuroś, Doctoral Dissertation (2002)
: NN only : NN with TM-3NF : AV18+UrIX-3NF : CD-Bonn
+TM’-3NF
12 = 1 2
Measurements along the S-curve around the FSI configuration (1= 2 , 12 =0) is good probe to make a discrimination between the present 3NF models !!
Measurements along the S-curve around the FSI configuration (1= 2 , 12 =0) is good probe to make a discrimination between the present 3NF models !!
We chose the configuration of p1= n to avoid the Coulomb force acting between two nucleons in FSI.
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Experiment at RCNP
p+d (p+n)+p @ 250MeV ; Differential cross sections & Ay
Two protons Detected by using double-arm spectrometer
Neutron in FSI Not detected
p
p
n
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Experimental procedure
Configuration: (p1= n = 40 deg , 1n = 0 deg) (p1= 40 deg, p2 ~ 67 deg , 12 = 180 deg)
polarized proton beamEp = 250 MeVB.I. = 50 nA
polarization ~ 70 %
LAS = 40degEp1 = 50 ~ 115 MeV
GR ~ 67 degEp2 = 116 ~ 120 MeV
CD2 targetLiq D2 target
S-curve
S=0[MeV]
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Liquid deuteron target
Target thickness about 30 mg / cm 2 Thickness of aramid foils 12m
Monitoring of the target thickness by the measurement of pd elastic scattering θp = θd = 50.8deg (LAB)
Calibration of the absolute values of the data
Deuterated polyethylene ( CD2) 5 0 mg / cm 2 Graphite
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Missing Mass & S-curve
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Results
Vector analyzing powers S = 7 MeV-bin
Statistical errors Ay < 0.02
Differential cross sections
The analysis is in progress.
dp breakup at 250MeV
dp breakup at 200MeV
Preliminary
Preliminary
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Summary
250 MeV pd breakup measurements were performed at RCNP. p1= n = 40 deg , 1n = 0 deg configurations were measured by detect
ing two protons.
S = 30 – 125 MeV range including FSI.
Results Vector analyzing powers were obtained with Ay < 0.02.
Data will be compared with the theoretical predictions with/without 3NF.
The results of the differential cross sections are coming soon.
13
Thank you for your attention.
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Results
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Our proposal
To search the detail of the 3NF effects and make a discrimination between 3NF models, we propose to perform p+d (p+n)+p break up measurement at … Ep = 250 MeV
Observable: Ay
Configuration: (p1= n = 40 deg , 1n = 0 deg)
(p1= 40 deg, p2 ~ 67 deg , 12 = 180 deg)
Large 3NF effects
Difference between 3NF models
S-curve
S=0[MeV]
Experiments at RCNP• 250MeV d(p,p)pn ; Cross section & Ay• 100MeV/A p+d (pn)1So + p ; Cross section, Ay, Ayy, Axx, Axz
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Kinematics
• 1, n = 29 – 31 deg (dashed lines)
• S = 80 – 170 MeV ; E1 = 115 – 50 MeV
• Data points Ay ; 7 points, Ay = 0.01 – 0.02 Ky
y’ ; 2 points, Kyy’
= 0.04
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Coulomb interaction
It is difficult to include Coulomb force into the Faddeev calculations. Comparison between d+n Faddeev calculations and d+p data.
How large is the Coulomb effect in the intermediate energy region? Calculation including Coulomb force approximately. Data is well reproduced by including the Coulomb force at the forward a
ngular region. Large difference between calculations with/without Coulomb interaction.
NN:AV14 calculations by Prof. Koike
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2-exchange 3NF models
parameter offcut:
factorformπNN)(22
2222
q
mqF NN
3NF model a b c d
FM
TM
Urbana IX
TM’
0.0
1.13
0.0
-0.87
-1.15
-2.62
-1.20
-2.62
0.0
1.05
0.0
0.0
-0.29
-0.60
-0.30
-0.60
p-wave
s-wave
b, d
a
c