Recent experiments on three nucleon systems and problems to be solved
Kenshi SagaraKyushu U. , Fukuoka, Japan
FB19
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Basic process
High momentum transfer
Various configurationsQFS, FSI, Star, Collinear, ..
Experiments in Nd system
3-nucleon forces3-body effects
Systematicexperiments
Calculatonswith 2NF+3NF+
Ay puzzle1986 Ay puzzle
pd CS discrepancy1994-1996-1997
(Sagara discrepancy)
3N BE problem1980’s
3NF(FM)was found
1998pd breakup discrepancy
pd captureAjj anomaly
3NF?3NF?relativity?
Space Star anomaly1989
-- higher energy discrepancies --
pd sactt. discrepancy
-- lower energy discrepancies --
-- lower energy discrepancies --
Off-plane Sar anomalyQFS anomaly
???
???
Discrepancies in 3N systems and their origins
FM-3NF1957
Systematic measurements
We are here.
Faddeeveqs. 1960
Ay at EN =5-18 MeV (~1994)
++Ay puzzle
nd Ay & pd AyEN=10MeV
pd Ay Ep=22.7MeV
Modification factors
H. Witala and W. Gloeckle, NPA528 (1991)48
NN forces 3P0
3P13P2
np 1.04 1.07 1.03
pp 0.86 1.05 1.02
nn 0.75 1.08 1.03
A suggestion to solve Ay puzzleModified calculations
Original calculation
Ay puzzle
Modification of LS force in 2NF
Modification of 3PJ forces in 2NF
Addition of LS force in 3NF
Adjusting of forces in PT
3NF effects?
Relativistic effects?
or ………..
Origin(s)
Ay puzzle is a long-standing problem since 1986 (FB11).
Shortage of 3H binding energy (1980’s)
(Experiment)
8.482MeV
(Theory)
2NF
~1MeV shortage
3H B.E. can be reproducedby adjusting a parameter in 23NF
Another evidence was necessary to confirm 23NF
Systematic measurement of pd scattering cross section (1994)
Here are discrepancies
18MeV
10MeV
5MeV
12MeV
+ +
pd cross section (RIKEN 1996)
+ +
nd calculation by Koike30% difference
+ +
RIKEN data (1996)Kyushu data (1994)
Koike’s talk at FB15 (KVI)
H.Witala et al., Phys Rev Lett. 81 1183(1998)
8.482MeV (exp.)
2NF
23NF
Binding energy
+ +
23NF
Fujita-Miyazawa (1957)41 years
2p3NF was found (1998)
Scattering cross section
Ay puzzle1986 Ay puzzle
pd CS discrepancy1994-1996-1997
(Sagara discrepancy)
3N BE problem1980’s
3NF(FM)was found
1998pd breakup discrepancy
pd captureAjj anomaly
3NF?3NF?relativity?
Space Star anomaly1989
-- higher energy discrepancies --
pd sactt. discrepancy
-- lower energy discrepancies --
-- lower energy discrepancies --
Off-plane Sar anomalyQFS anomaly
???
???
Discrepancies in 3N systems and their origins
FM-3NF1957
Systematic measurements
We are here.
Faddeeveqs. 1960
pd capture experiment
+ +
○ high momentum transfer → short-range 3NF
× Reaction cross section is very small (< 1 barn).
Experimental techniques•thick target & low BG → liquid hydrogen target •high-efficiency detection → one-shot measurement of whole angular distribution
Side View(enlargement)
12
Front View
Liquid Hydrogen Target 精密実験に不可欠
m
Vertical planefor Axx
Horizontal planefor Ayy & Ay
(3He) < 4.7
Whole angular distribution was measured in one shot.
Y
BG level was low
Axx anomaly in pd capture at Ed = 200 MeVfrom RCNP exp. (Yagita et al. 2002)
2 NF2 NF +3 NF
Calc. by Witala et al.
0 50 100 150
0.2
0.0
0.2
0.4
0.6
Axx
C.M angle (deg.)0 50 100 150
0.2
0.0
0.2
0.4
Ayy
C.M angle (deg.)
0 50 100 150
0.2
0.1
0.0
0.1
0.2
Ay
C.M angle (deg.)0 50 100 150
0.5
0.4
0.3
0.2
0.1
Cro
ss
sect
ion
(m
b/s
r)
0.0
C.M angle (deg.)
Axx anomaly? Axx~Ayy?
Ajj of pd-capture were measured also at KVI, and KVI data agreed with calculations.
Axx Ayy
Azz
● ○ RCNP(200MeV)■ □ KVI ( 180MeV)
RCNP data at 137MeV also disagreed with KVI data at 133MeV.
Experiment at KVI, Ayy & “Azz” (=-Axx-Ayy )
Big-Bite spectrometer (BBS) & Plastic Ball detector (PB)
-detectionAzz :45±10 degreeAyy : 0±15 dergree
Azz = -Axx-Ayy
Beam axis
d + p→3He+EdeV
(3He) < 4.7deg
Slit in front of LAS
“Azz ” = (Axx-Ayy)Axx Ayy
Beam polarization is along y-axis.
Re-measurement at RCNP at 200 MeV
Liuqidtarget
Emptytarget
Background subtraction
BG
True
y
y
polarized beam
unpol. beam
Detection efficiency
Single cluster
Multiple cluster
Overlapped cluster & single cluster
Overlapped–overlapped clusterOther rays
~83%
~2%
~14%
~1%
Efficiency =.834 =0.48Standard data analysis
Efficiency =.974 =0.88
Efficiency =.994 =0.96Multi-II data analysis
X1
X2
X1
X1
X2
X2
Backgroun estimation was much improved by a multi-II method.
Total 100%
X1
X2
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 30 60 90 120 150 180
Axx 196MeV
AxxYag
AxxMII
theta
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 30 60 90 120 150 180
Ayy 196MeV
AyyYag
AyyMII
theta
Single cluster data analysis vs. Multi-cluster II data analysis (new)
2002 exp.
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 30 60 90 120 150 180
Axx 196MeV
AxxAxx126Axx2NFAxx3NF
theta
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 30 60 90 120 150 180
Ayy 196MeV
AyyAyy126Ayy2NFAyy3NF
theta
d+p→3He+
New data and previous data (new multi-II analysis)2002present
-0.2
0
0.2
0.4
0.6
0.8
1
0 30 60 90 120 150 180
Azz 196MeV
AzzAxxyyAzz126Azz2NFAzz3NF
theta
d+p→3He+
New data and previous data (Multi-II)present 2002
-(Axx+Ayy)
-(Axx+Ayy)
“Azz”
-0.2
0
0.2
0.4
0.6
0.8
1
0 30 60 90 120 150 180
Azz data
AzzAxxyyAzz126Azz2NFAzz3NFAzzKVI
theta
KVI data at 180 MeV
RCNP data at 196 MeV
Calc. at196 MeV
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 30 60 90 120 150 180
Ayy 137MeV
Ayy137Ayy2NFAyy3NF
theta
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0 30 60 90 120 150 180
Axx 137MeV
Axx137Axx2NFAxx3NF
theta
pd radiative capture at Ed = 137 MeV(multi-II analysis)
Ajj in pd capture
Axx anomaly (Azz anomaly) has been confirmed.
Axx ~ Ayy ---> axial symmetry ?Azz > calculation ----> short range reaction?
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pd scattering CS at 250 MeV E-dependence of CS at 150 degree
++
exp
/cal
at
= 1
50⁰
23NF
=150⁰
J. Kuros-Zoluierczuk et al., PRC66, 024003 (2002).
D(p,pp)n CS at 250 MeV + + +
d
p
p
detected
un-detected
d
p
p
detected
p detected
Inclusive exp. at 250 MeV D(p,p)pn experiment (global feature)
Exclusive exp. at 250 MeV D(p,pp)n experiment (microscopic study)
--> Kuroita’s talk
+ + +
pd breakup CS at 250 MeV, inclusive & exclusive
Large (~2 times) CS enhancement
pd & nd scattering CS above 150 MeV
Short-range 3NF?Relativity?……..?
++
+ + +
+ + +Space star anomaly around 10 MeV
α=144º
α=124º
~ QFS~ QFS
~ QFS~ QFS
En
Is there QFS anomaly in addition to space star anomaly?
+ + +QFS anomaly?
Result (pp-QFS)
QFSQFS
Ep= 9.5 MeV Ep= 13 MeV
QFSQFS
~7% smaller~7% smaller ~9% smaller~9% smaller
star
pd QFS
Ep= 9.5 MeV
Ep= 13 MeV
A. Siepe et al., Phys. Rev. C 65, 034010 (2002)
~ 18%
θ1= θ2= 42 deg.
θ1= θ2= 42.2 deg.
~ 16%
X. C. Ruan et al., Phys. Rev. C 75, 057001 (2007)
nd QFS
pd QFS
Also there are nd QFS (2002,2007), and CS of nd QFS is higher than calculation, CS of pd QFS is lower than calculation.
+ + +
①②③
④⑤
⑥⑦
Ep= 9.5 MeV
Ep= 13 MeV1
5
4
23
6
7
Angular dependence of QFS anomaly
Nd breakup cross section at low energy
Star anomaly appears only around space star ( = 90 °) at 13 MeV, and in a wide angular region at 9.5MeV.
Large CSB occurs, nd CS> calc, and pd CS < calc.
Star anomaly
QFS anomaly
CS anomaly also appears in pd QFS and nd QFS. QFS anomaly appear s in a wide angular region.
Large CSB occurs, nd CS> calc, and pd CS < calc.
What origin(s)
Same origin or different ones?
Ay puzzle1986 Ay puzzle
pd CS discrepancy1994-1996-1997
(Sagara discrepancy)
3N BE problem1980’s
3NF(FM)was found
1998pd breakup discrepancy
pd captureAjj anomaly
3NF?3NF?relativity?
Space Star anomaly1989
-- higher energy discrepancies --
pd sactt. discrepancy
-- lower energy discrepancies --
-- lower energy discrepancies --
Off-plane Sar anomalyQFS anomaly
???
???
Discrepancies in 3N systems and their origins
FM-3NF1957
Systematic measurements
We are here.
Faddeeveqs. 1960
More systematic experiments on some reactions
More challenging calculations with new 3NF, new frame, …
remaining 3NF’sunknown 3-body effects…….
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