pd 捕獲反応のテンソル偏極量の異常

pd 捕獲反応のテンソル偏極量の異常

K. Sagara1, Y. Tameshige2, K. Hatanaka2, S. Kuroita1, H. Matsubara2, K. Fujita1, Y. Shimizu2, T. Kawabata3, Y. Maeda5, Y. Sakemi, H. Okamura2, K. Sekiguchi4, A. Tamii2, and T. Wakasa1

1Dept. of Physics, Kyushu University2RCNP, Osaka University3CNS, University of Tokyo4RIKEN, 5CYLIC, Tohoku University6Dept. of Engineering, Miyazaki University

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 anomaly

???

???

Discrepancies in 3N systems and their origins

FM-3NF1957

By Koike’s talk at Few-Body Conf. at KVI (1997), CS minimum discrepancy was widely recognized.

+

+

+ +

+

3NF found

High momentum transfer

Wide phase space

Experiments in pd system

pd capture experiment

+ +

○ 　 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

m

Vertical planefor Axx

Horizontal planefor Ayy & Ay

(3He) < 4.7

Whole angular distribution was measured in one shot.

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.

KVI での測定 , Ayy & Azz (=-Axx-Ayy )共通点• 液体水素標的• pyy ビーム

KVI

• A ｙｙ , A ｚｚ

• 散乱平面は PB で決定• 3He- のののののののの測定　　綺麗に測定（統計が少ない）　 Azz→ 実際は -(Axx+Ayy) を測定

Big-Bite spectrometer (BBS) & Plastic Ball detector (PB)

検出角度Azz :45±10 度Ayy : 0±15 度

Azz = -Axx-Ayy

ビーム軸 から見た PB 検出器　

d+p → 3He + Ed = 140 MeVat RCNP

preliminary

Ayy Axx

BG 多く、データ解析進まず

We made a new experiment (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)

d + p→3He+EdeV

(3He) < 4.7deg

Slit in front of LAS

Azz=(Axx-Ayy)Axx Ayy

Beam polarization

Liuqidtarget

Emptytarget

Background subtraction

BG

True

y

y

polarized beam

unpol. beam

Y

In previous exp. BG level was low.

LAS 0° Data Analysis

projection

Data at 140 MeV, BG 多い

A = [ (Ytrue)pol / (Ytrue)unpol – 1 ] / pbeam

= [ (Ytot-YBG)pol / (Ytot-YBG)unpol – 1] / pbeam

Y = (Ncount /Qbeam) /efficiency

Efficiency should be high to obtain reliable data.

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

X1

X1

X1

X2

X2

Detection efficiency was much improved by a multi-II method.

Total 100%

-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

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 (Multi-II)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

-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)

Summary

Axx, Ayy, and Azz (= -Axx-Ayy) of pd radiative capture at Ed = 196 MeV were measured again at RCNP.

Data were analyzed with 96% detection efficiency by multi-cluster-II method.

Also previous RCNP data at 196 MeV were re-analyzed by multi-cluster-II method.

New and previous data agree well, and

Axx (Azz) anomaly in pd capture was confirmed.

Also at 137 MeV, Axx anomaly in pd capture was confirmed.

Axx ≈Ayy relation was also confirmed.

The Axx (Azz) anomaly can not be explained by 3NF, and new forces or mechanisms may be necessary.

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