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Systematic Experiments on UnsolvedAnomalies in 3N breakup Reactions
Kenshi Sagara ( Kyushu University)
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3N bound state
Scattering & reactions
Ay puzzle1986
Ay puzzle
pd CS discrepancy1994-1996-1997
(Sagara discrepancy)
3N BE problem1980’s
3NF(FM)was found
1998
pd breakup discrepancy
pd captureAjj anomaly
3NF?3NF?relativity?
Space Star anomaly1980’s
higher energy discrepancies
pd sactt. discrepancy
lower energy discrepancies
lower energy discrepancies
Off-plane star anomalyQFS anomaly?
???
???
Discrepancies in 3N systems and their origins
FM-3NF1957
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23NF confirmed in BE and CS.Complex discrepancies remain in AP’s.
Axx~Ayy, Axx anomalyNew 3NF at higher energy?
Discrepancies at higher energy
Discrepancies at lower energy
3H binding energy
(Experiment)
8.482MeV
(Theory)
2NF
~1MeV 23NF?
23NF has an adjustable parameter.
3H binding energy alone is not the evidence of 23NF.
Systematic measurement of pd scattering Ay at Ep =2-18 MeV at KUTL(1994)
E-dependence of Ay puzzle (1994)
Ay puzzle is not related to 23NF.Ay puzzle is a puzzle still now.
Discrepancy of-10% ~ -40%
Measurement of cross section within 1% accuracy was a hard work.
Energy spectrum of pd scattering
pd scattering cross section at 2-18 MeV were measured systematically(1994)
Exp. errors < 1%. Data were “well” reproduced by 3N calculation. What is the output from this precise experiments?
At the cross section minimum, large discrepancy in relative value was found. (Comapred to Approx.CoulombCalculation)
CS discrepancy is comparable to Ay puzzle. But, no one paid attention to this fact !
I appealed this fact to Koike, but Koike did not believe it.
At RIKEN, pd scattering was measured to construct a d-beam polarimeter.
30% discrepancy at CS minimum was found also at Ed = 270 MeV. Coulomb effects are small.
Koike believe the CS discrepancy.
pd data from SMARTKoike’s nd calculation
N. Sakamoto et al., (1996)
The first contribution from SMART
By Koike’s talk at Few-Body Conf. at KVI (1997), CS minimum discrepancy was widely recognized.
H.Witala et al., Phys Rev Lett. 81 1183(1998)
Discrepancy at CS minimum was excellently explained by 23NF.The same 23NF also reproduces 3N binding energy.
Existence of 23NF was confirmed (1998), after 41 years since Fujita-Miyazawa theory (1957).
23NF boom from1998
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3NF searches started
RIKEN, KVI, RCNP, IUCF, ・・
KUTL, RCNP, KVI
KUTL, RCNP
Ed=140MeV
Ed=200MeV
Ed=270MeV
Ayd Axz Ayy Axx
K. Sekiguchi et al.
Pd scattering CS is well reproduced by including 23NF, but Polarization observables can not be reproduced by 23NF.
Strategy of Kyushu group
Search for new 3NF’s other than 3NF (3NF, 3NF)
in pd capture reaction and pd breakup reaction
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Kyushu G experiments (→new 3NF)
pd capture experiment
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○ Short-range forces may play important roles. (→new 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
Vertical planefor Axx
Horizontal planefor Ayy & Ay
(3He) < 4.7
Whole angular distribution was measured in one shot.
Y
Data analysis for Axx
Data analysis for Ayy & Ay
pd capture at Ed = 200 MeV 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)
We made new experiments (present exp.) at RCNP.
Beam : 197 MeV (same as before)Target : Liquid Hydrogen (same as before)Detection: 3He (same as before)
Observables: Axx (same as before) Ayy (same as before) Azz (= -Axx-Ayy) (similar to KVI)
-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)
Axx ~ Ayy in pd capture
KVI
RCNP
A xx
Ayy
AyyAxx
Ayy & Axx measured
Only Ayy measured
Why Axx ~ Ayy holds in pd capture?
Is it a signal of new 3NF?
d-α elastic scattering Ed=15MeV d-3He breakup
Nucl. Phys. A265 280(1976)
Nucl. Phys. A334 365(1980)
Except for pd capture, Axx~ -Ayy holds in general
Ayy
Axx
yyxx AA
Axx Axx
AyyAyy
Ayy < 0
Axx < 0
pd capture reaction
Axx ~ Ayy <0
Ayy > 0
Axx < 0
d-induced reaction in general
Axx ~ -Ayy
Peripheral region ?Axial symmetryCentral region ?Short-range force ?
Ay puzzle1986
Ay puzzle
pd CS discrepancy1994-1996-1997
(Sagara discrepancy)
3N BE problem1980’s
3NF(FM)was found
1998
pd breakup discrepancy
pd captureAjj anomaly
3NF?3NF?relativity?
Space Star anomaly1980’s
higher energy discrepancies
pd sactt. discrepancy
lower energy discrepancies
lower energy discrepancies
Off-plane star anomalyQFS anomaly?
???
???
Discrepancies in 3N systems and their origins
FM-3NF1957
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pd breakup experiments
At Ep = 250 MeV to search new 3NF effects
At around Ep = 13 MeV to study Star Anomaly
Ay at 250 MeV
3NF effects relativistic effects
2NF only2NF+3NF
Non-relativisticRelativistic
K. Hatanaka et al., PRC66 044002(2002)Y. Maeda et al., PRC76 014004(2007)
Cross section at 250 MeV
Cross Section
Cross Section at 250 MeV Cross Section Ratio (Exp/Calc)
Elastic
Break-up
At 250 MeV, BU cross section is ~5 times larger than elastic scattering cross section
GR
LAS
p - beamLiq D2
Target
CS at 250 MeV Only p1 detected
p1
p2 np1
First experiment
CS at 250 MeV Only p1 detected
2NF+3NFOnly 2NF
nd calc.by H. Witala
p2 np1
CS at 250 MeV Only p1 detected
2NF+3NFOnly 2NF
nd calc.by H. Witala
p2 np1
2NF+3NFOnly 2NF
nd calc.by H. Witala
Ay at 250 MeV Only p1 detected
detected p1
free
We first investigate discrepancy in cross section
CS at 250 MeVOnly p1 detectedp2 np1
p1 and p2 detected
p2
p1
ABC
A
C
B
1-dependence at different E1
1
E1
detected p1
free
p2
p1
We selected energy B
detected p1
free
detected p1
detected p2
2NF+3NF2NF Calc by H. Kamada
2-dependence with 1 fixed at15 degreeand12 = 180 degree
12-dependencewith 1 and 2 fixed at15 degree and 35 degree
12
1 12
1
2NF+3NF2NF Calc by H. Kamada
2-dependence with 1 fixed at15 degreeand12 = 180 degree
12-dependencewith 1 and 2 fixed at15 degree and 35 degree
12
1 12
1
GR
LAS
p - beamLiq D2
Target
p1
p2
CS at 250 MeVp2 np1
p1 and p2 detected
GRVDC + E scintillator
Momentum accept.:2.5%
• GRとLASの相対角度の最小値は約50o
Unpolarized p-beam
Liq D2
Target
D(p,p1p2)n CS at 250 MeV
p1 and p2 detected
LASVDC + E scintillator
Momentum accept. :2.5%
• GR と LASの相対角度の最小値は約 50o
p2 np1
Liquid D2 target
Previous data were confirmed. New data were added. 3NF effects
Same data. Relativistic effects.
Same data. 3NF effects and relativistic effects.
True+BG
BG
1 =15 degree and 2 =35 degree
Check of the absolute cross section
Calc. by H. Witala3NF effects 2NF+3NFOnly 2NF
Calc. by H. WitalaRelativistic effects RelativisticNon-relativistic
Calculation by H. Witala
3NF effects and relativistic effects
3NF effects and relativistic effects
x 5.8
If 3NF effects are artificially 5.8 times increased, experimental CS data are roughly reproduced.
Arb
itra
ry u
nit
Possible enhancement of 3NF at higher energy
Summary
At 250 MeV, pd breakup cross section were measured by First, detecting 1-protons from p+d p+p+n reaction, Second, detecting 2-protons in coincidence.
Large discrepancy of about 2 times in CS was observed.The discrepancy occurs in a wide angular region.
3NF effects are too small (5.8 time) to explain the discrepancy, also relativistic effects are too small to explain the discrepancy.
CS discrepancy monotonically increases with energy. New 3NF may be necessary to explain the discrepancy.
Ay puzzle1986
Ay puzzle
pd CS discrepancy1994-1996-1997
(Sagara discrepancy)
3N BE problem1980’s
3NF(FM)was found
1998
pd breakup discrepancy
pd captureAjj anomaly
3NF?3NF?relativity?
Space Star anomaly1980’s
higher energy discrepancies
pd sactt. discrepancy
lower energy discrepancies
lower energy discrepancies
Off-plane star anomalyQFS anomaly?
???
???
Discrepancies in 3N systems and their origins
FM-3NF1957
The origin of Space Star anomaly
Space Star : configuration of three outgoing nucleons form an equilateral triangle and have the same energy
Blue line : nd calc Red Line : pd calc
Space Star
nd : exp > calcp d : exp < calc
calc : coulomb effect is very small
c.m. system
n+d→n+n+p
p+d→p+p+n
Off-Plane Star anomaly
Cross Section reported by Koeln Univ.
Define the angle between Star plane and beam axis, α
α=90° Space Star
Large anomaly is shown
c.m. system
Ed=19MeV
Off-Plane Star anomaly
Cross Section reported by Koeln Univ.
Define the angle between Star plane and beam axis, α
α=90° Space Star
Large anomaly is shown
c.m. system
Ed=19MeV
Experiment
Observable : Cross Section
Incident Energy :Ed = 19 MeV
Target : CH2 foil ( rotary target )
Detector : Si-SSD
Set up of scattering chamber
1 2
T1-T2[ns]
T(E
1)-T
(E2)
[ns]
Break up event
E1 [MeV]
E2
[MeV
]
S curve
11
2212 22
)()(E
mL
E
mLETET pp
mp : proton massEi : energy of detected protonLi : length between target and detector
Remove B.G.
E2
[MeV
]E1 [MeV]
B.G.+ true
E2
[MeV
]
E1 [MeV]
B.G. only
1 2
Ed=19MeV
calc : Mr.Deltuva
Present data
Koeln data
Only Space Star Anomaly (~90º ) exists.We used an unpolarized beam to carefully measure cross section.
Why Space-Star anomaly appears is the next problem.We will make systematic experiments at perpendicular plane.