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

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pd cross section (RIKEN 1996)

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nd calculation by Koike30% difference

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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

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○ 　 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

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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

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pd breakup CS at 250 MeV, inclusive & exclusive

Large (~2 times) CS enhancement

pd & nd scattering CS above 150 MeV

Short-range 3NF?Relativity?……..?

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+ + +

+ + +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.

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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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