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

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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

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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

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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.