Dept. of Phys., Kyushu Univ.
Measurement of 2H(p,pp)n cross sections
at Ep = 250 MeV
Sho Kuroita1,
K. Sagara1, Y. Eguchi1, K. Yashima1, T. Shishido1, T. Yabe1,
M. Dozono1, Y. Yamada1, T. Wakasa1, T. Noro1, H. Matsubara2
J. Zenihiro2, A. Tamii2, H. Okamura2, K. Hatanaka2, T. Saito3
Y. Maeda3, H. Kamada4, Y. Tameshige5
1: Department of Physics, Kyushu University
2: Research Center for Nuclear Physics (RCNP), Osaka University
3: Department of Applied Physics, University of Miyazaki
4; Department of Physics, Faculty of Engineering, Kyushu Institute of Technology
5: National Institute of Radiological Sciences
Dept. of Phys., Kyushu Univ.
1957 Fujita – Miyazawa suggested the existence of three nucleon force.
Then 2p-exchange three nucleon force (2p3NF) models were created, and
these 2p3NF well described binding energies of nuclei were constructed
by few nucleon.
NN only NN+TM-3NF
CD Bonn 8.0 MeV
Nijm II
7.6 MeV
AV18
7.6 MeV
8.5 MeV
8.5 MeV
8.5 MeV
8.5 MeV
Exp.
Differential cross sections of pd scattering below EN = 140 MeV were
well described by including 2p3NF in Faddeev calculations.
Cross sections of pd elastic
scattering at Ep = 65, 140 MeV
NN + TM3NF
NN only
65 MeV
2009/9/3
140 MeV
FB19 - Bonn University, Germany
H. Witala et al., PRL81 (1998) 1183.
2
Dept. of Phys., Kyushu Univ.
Besides 2p-exchange 3NF, heavymeson exchange 3NF are
predicted in cPT.
These heavy-meson exchange
3NFs are expected that the effects
become larger at high energy
region.
2009/9/3
FB19 - Bonn University, Germany
3
Dept. of Phys., Kyushu Univ.
EN = 250 MeV Nd elastic scattering
K. Hatanaka et al., PRC66 044002 (2002).
Y. Maeda et al., PRC76 014004 (2007).
NN + TM3NF
NN only
＊The disagreement of pd elastic
scattering become larger at higher
incident energy.
p-threshold
＊And the disagreements are not
related to π-threshold
Above EN = 140 MeV, cross section of pd elastic scattering does not
described by Faddeev calculation with 2π3NF.
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
So we have measured cross section of pd breakup reaction in order to
investigate origins of the disagreement on Nd scattering cross section.
At intermediate energies, Nd breakup
reaction is main reaction process
in 3N systems.
J. Kuros-Zoluierczuk et al.,PRC66, 024003 (2002).
We measured cross section and analyzing power Ay of inclusive pd
breakup 2H(p,p)pn reaction at Ep = 247 MeV to study the global feature of
pd breakup reaction at intermediate energy region.
Angle is free !
detected
p1
Observable : cross section, Ay
(E = 70 ~ 230 MeV)
Angle
: 10, 15, 20 deg.
Detector
: Spectrometer (LAS@RCNP)
VDC, Scintillator
Target
: Liquid Deuterium
Calc. by H. Witala, private communication
2009/9/3
FB19 - Bonn University, Germany
5
Dept. of Phys., Kyushu Univ.
nd calculation by Prof. H. Witala
Even after inclusion of 2π3NF , large disagreements remain.
The experimental cross section is about 1.8 times larger than calc.
at 15 deg .
First, we pay attention to only the disagreement of cross sections.
2009/9/3
FB19 - Bonn University, Germany
6
Dept. of Phys., Kyushu Univ.
pd calculation by A. Deltuva
pd calculation indicate Coulomb effect slightly decreases cross section.
To sum up, the orign(s) of the disagreement is not Coulomb effcet.
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
2H(p,p
1)pn
reaction == previous experiment ==
Angle is free !
detected
p1
2H(p,p
1p2)n
reaction == New experiment ==
q2
q1 = 15°fixed
E1 = 150 MeV
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
Dependence of cross section for q2
d3s/dW1dW2dE(15f, 150 MeV, q2, 180f)
3N calculation for 2H(p,p1p2)n
reaction at 250 MeV suggests that
2H(p,pp)n cross section has the
maximum at q2 ~ 35 deg.
Calc. by Prof. H. Kamada
q2
Dependence of cross section for f12
d3s/dW1dW2dE(15f, 150 MeV, 35f, f12)
Also 3N calculation suggests that
2H(p,p p )n cross section has the
1 2
maximum at f12 = 180 deg.
So we measure cross section at
f12 = 180 deg.
2009/9/3
FB19 - Bonn University, Germany
f12
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Dept. of Phys., Kyushu Univ.
2H(p,pp)n
breakup reactions at Ep = 250 MeV
250 MeV proton beam from RING cyclotron @ RCNP
WS course in West exp. Room
Observable : Cross section
target :
Liquid deuterium
GR
CD2
Detector :
GR (spectrometer)
LAS (spectrometer)
Scintillator
Scatt. Chamber
Luminosity monitor
* Liq. D2
dp elastic scattering
(kinematical coincidence)
LAS
Configuration
2H(p,p p )n reaction
1 2
q1 (GR) = 15 deg fixed
q2 (LAS) = 35, 50, 65, 80 deg
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
We used liquid deuterium target system as deuteron target . Liquid
deuterium target is an almost pure and very thick deuteron target, and it
enables low background experiments.
Thickness
: ~ 220 mg/cm2, (target length = ~12 mm)
Cell temperature
: ~ 18 K (cooled by Cryo – refrigerator)
(monitored by Si diode thermometer)
The thickness of liquid deuterium (liq. D2) target is varied by condition
of cell temperature and gas pressure e.t.c..
So we monitored the thickness by using coincidence measurement of
pd elastic scattering simultaneously.
Cryo
- refrigerator
Liq. D2 target cell
Heater
expand !
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
We have measured cross sections of 2H(p,p1)pn
reaction to check the disagreement of the previous
2H(p,p)pn cross sections at 250 MeV in the same setup.
expand
preliminary
Calc. by Prof. H. Witala
preliminary
We have reconfirmed the large disagreement of 2H(p,p1)pn cross section
between experimental data and Faddeev calculation including 2p3NF.
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
q1 (GR) = 15 deg, q2 (LAS) = 35 deg, f12 = 180 deg.
True + B.G. event
q1 momentum
B.G. event
q1 momentum
B.G. subtract
E1 [MeV]
2009/9/3
E1 [MeV]
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13
Dept. of Phys., Kyushu Univ.
Calc. by Prof. H. Kamada
q2=50 deg
q2=35 deg
q1=15deg,
E1=150 MeV
preliminary
E1=150 MeV
preliminary
preliminary
preliminary
2009/9/3
q1=15deg,
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Dept. of Phys., Kyushu Univ.
q2=65 deg
Calc. by Prof. H. Kamada
q2=80 deg
q1=15deg,
q1=15deg,
E1=150 MeV
preliminary
preliminary
preliminary
preliminary
2009/9/3
E1=150 MeV
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Dept. of Phys., Kyushu Univ.
Dependence of cross section for q2
d3s/dW1dW2dE(15f, 150 MeV, q2, 180f)
The cross sections of 2H(p,p1p2)n
reaction at 250 MeV have the
maximum at q2 = 35 deg.
The ratio of the disagreement of
2H(p,p p )n cross section have also
1 2
has the maximum at q2 = 35 deg.
And the ration become smaller at
backward angles.
Calc. by Prof. H. Kamada
preliminary
q2 = 35°,50°,
65°,80°
q1 = 15°fixed
E1 = 150 MeV
preliminary
2009/9/3
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FB19 - Bonn University, Germany
16
Dept. of Phys., Kyushu Univ.
Calc. by Prof. H. Kamada
q2=50 deg
q2=35 deg
q1=15deg,
E1=150 MeV
preliminary
E1=150 MeV
preliminary
preliminary
preliminary
2009/9/3
q1=15deg,
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
We have measured cross sections of 2H(p,p1p2)n reaction at
E1 = 150 MeV, q1 = 15 deg fixed, q2 = 35, 50, 65, 80 deg. (total 4 setup).
Simultaneously, we have measured cross section 2H(p,p)pn reaction
and confirmed the large disagreement between experimental data
and Faddeev calculations including 2p3NF.
The preliminary result of 2H(p,pp)n cross sections suggest large
disagreements between experimental data and calculations as same as
2H(p,p)pn reaction.
We think that origin(s) of these
discrepancy is
Heavy-meson exchange 3NF
pr3NF, rr3NF, e.g..
preliminary
~
x
1.8
Relativistic effect
So we will have to study relations
between these disagreement and
candidate of origin(s).
2009/9/3
FB19 - Bonn University, Germany
18
Dept. of Phys., Kyushu Univ.
Nd elastic scattering (s, Ay, Kij)
… RCNP, RIKEN, KVI etc
(EN > 140 MeV)
pd radiative capture (s?, Aij)
… RCNP (Ed = 200 MeV)
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
The disagreements of cross sections for 2H(p,p1)pn at 250 MeV become
larger at forward angles. Dose the disagreements vanish at backward
angle ?
Previous exp.
2H(p,p )pn reaction
1
3
2
3
1
2009/9/3
detected
p1
1
2
So we have also measured cross sections
of 2H(p,p)pn reaction at backward
angles to see whether the discrepancy
exist at backward angles.
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
Why d3s/dW1dW2dE(15f, 150 MeV, ~35f, 180f) has a maximum ?
When q1 = 15 deg and E1 = 150 MeV, q2 =36 deg, 2H(p,p1p2)n reaction
is in “Collinear configuration”.
3N calculations predict cross section has maximum at Collinear
configuration.
q1= 15 deg (lab.)
E1 = 150 MeV
Whether SR3NF effects dominate in collinear configuration or not is
also an interesting subject ?
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
So we have measured cross section of pd breakup reaction in order to
investigate origins of the disagreement on Nd scattering cross section.
At intermediate energies, Nd breakup
reaction is main reaction process
in 3N systems.
J. Kuros-Zoluierczuk et al.,PRC66, 024003 (2002).
We measured cross section and analyzing power Ay of inclusive pd
breakup 2H(p,p)pn reaction at Ep = 247 MeV to study the global feature of
pd breakup reaction at intermediate energy region.
measured
Observable : cross section, Ay
(E = 70 ~ 230 MeV)
Angle
: 10, 15, 20 deg.
Detector
: Spectrometer (LAS@RCNP)
VDC, Scintillator
Target
: Liquid Deuterium
Calc. by H. Witala, private communication
2009/9/3
FB19 - Bonn University, Germany
22
Dept. of Phys., Kyushu Univ.
So we maybe think that the
strength / effects of 2p3NF are
also understood by studies of
binding energies of nuclei were
constructed by few-nucleon and
Nd elastic scattering.
But others of three-nucleon (3NF)
is not found, for example, pr3NF,
rr3NF that were the existence
expected.
Effects of these 3NF may be
found at higher energies because
these 3NF are the model exchange
heavier than p.
Besides 2p3-exchange NF, heavy-meson
exchange 3NF are redicted in cPT..
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
The disagreement of cross section exist at another energies, for example,
2H(p,n) reaction at E = 197 MeV by IUCF.
p
expand
Cross section of 2H(p,n) at IUCF
D.L. Prout et al., PRC65 034611 (2002).
In this experiment, cross sections for
2H(p,n) was measured at q = 13, 24, 37,
48 deg, and concentrated to QFS.
We have already systematic cross section data for 2H(p,p)pn reaction
at 250 MeV in wide energy region of reaction protons.
If we would performed a experiment for 2H(p,pp)n reaction, we
should measure cross section for 2H(p,p)pn to get information of
global feature and pp-FSI.
2009/9/3
FB19 - Bonn University, Germany
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Dept. of Phys., Kyushu Univ.
The discrepancy of 2H(p,p1)pn is the largest at around E1 = 150 MeV .
So we have measured cross sections for 2H(p,p1p2)n reaction around
E1 = 150 MeV at fixed q1 = 15 deg. in order to investigation origins for
the disagreement of 2H(p,p1)pn.
New exp.
2H(p,p p )n reaction
1 2
(microscopic study)
Previous exp.
2H(p,p )pn reaction
1
detected
p1
q2
q1 = 15°fixed
E1 = 150 MeV
Angle is free !
2009/9/3
FB19 - Bonn University, Germany
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