Tensor Analyzing Powers of pd Radiative Capture

Y. Tameshige, K. Sagaraa, T. Kudoha, M.Shiotaa, S. Shimomotoa, T.Wakasaa,

K. Hatanaka, A. Tamii, Y. Sakemi, Y. Shimizu, H.P.Yoshidaa,

H.Kamadab, and H. Witalac

RCNP Osaka University, aDepartment of Physics, Kyushu University

bFaculty of Engineering, Kyushu Institute of TechnologycDepartment of Physics, Yagellonian University

contents

• Introduction

• Experiment

• Results

• Summary &Future Plan

Introduction

N N N

CD Bonn

AV18

Nijm93

Ruhr

8.00

7.65

7.66

7.64

8.483

8.479

8.480

8.459

4.86

5.22

5.10

5.31

NN pot. NN only NN+3NF(TM) (m)

Exp. 8.48 MeV3H biding energy

N N N

Higher-order 3NF (short range)

N N N

However, even if 23NF is included,

polarization observables of pd scattering

can not be reproduced.

↓

Higher-order 3NF may be necessary.

Axz

Ed=

140MeV

Ed=

200MeV

Ed=

270MeV

Ayd Ayy

K. Sekiguchi et al.

Axx

NN NN+3NF

Adding a 3NF does not improve the description of the data.

indicating deficiencies in the spin-dependent part of present 3NF models

pd capture reaction may be a probe of short range forces.

N N N

Higher-order 3NF (short range)

N N N

However, even if 23NF is included,

polarization observables of pd scattering

can not be reproduced.

↓

Higher-order 3NF may be necessary.

Discrepancies in polarization observables

of pd scattering are complicated.

↓

Simple and clear signatures are required to

study higher-order 3NF.

+ +

Candidate to find out short distance three nucleon reaction

Present study: pd capture experiment

+ +

In pd capture reaction,

○　 Short-range forces may play important roles. (→short range

3NF)

× 　 Reaction cross section is very small (~ 0.1 barn).

Experimental techniques•thick target & low BG 　　→　 liquid hydrogen target •high-efficiency detection → one-shot measurement of whole

　　　　 　　　　　　　　　　　　　　　 angular distribution

p+d →3He+γ experiment at Ed = 137 MeV

Ayy (pure tensor)

(Pyy = -1.2)

Axx (pure tensor)

Experimental setup

1.5mm(10mg/cm2)

Ed = 137 MeV(4nA)

Vertical planefor Axx

Horizontal planefor Ayy

d + p→3He+(3He) < 4.1

Angular distribution in 20~160 was taken in one shot.

d-beam isvertically polarized

2°3°

4°5°Axx

Axx

FC shadow

Slit in front of LAS

Ayy

2° 3° 4° 5°

LAS acceptance horizontally ±3.4 [deg] ( ±60 [mrad])

vertically ±5.7 [deg] (±100 [mrad])

LAS at 2.5°LAS at 0°

Φ20

Liquid Hydrogen TargetExperimental setup

Data analysis

Raw data from liquid H2 target(normal target)

Backgroundsfrom windows(empty target)

X vs Y X vs θ

θcm=0°θcm=180°

θcm=20°

θcm=170°

Axx (0°) Ayy (2.5°)

Data analysis of Axx

projection

projection

Liquid Hydrogen target(normal target)Aramid foil target(empty target)

θcm=180°θcm=0°

X [mm]

Y [m

m]

0°

180°

Data analysis of Ayy

projection

θcm=20°

θcm=170°

Liquid Hydrogen target(normal target)Aramid foil target(empty target)

The same beam charge is the same background tail.

ExperimentalResults

Result at137MeV

present dataAV18AV18+URBIX

●- - -

―

AyyAxx

Calc. byKamada et al.

Measured Axx largely disagrees with calculations, and 2p3NF can not explain the difference

Ayy

137MeV

196MeV

Axx Axx

Axx

Axx & Ayy at 137MeV

Axx

Ayy

AV18 AV18+URBIX

●●

- - -―

Ayy AzzAxx

・　 Axx ~ Ayy means the reaction is z-axial symmetry.

x

y

beam

・　 Axx ~ Ayy <0 and Azz>0 means the reaction is dominant in the central region.

RCNP(137MeV) and at 133 MeV (KVI)AyyAxx

present dataKVI dataAV18AV18+URBIX

● （●）●

- - -―

(PRB617,2005,18) at 133MeV

・ The disagreement also exist at 196MeV(RCNP) and 188MeV(KVI) data.

・ We plan to measurements Azz at 196MeV to check the consistency our data.

・ Present data confirmed the Axx~Ayy relation and the large discrepancy in Axx. ・ Present data at 137MeV and 196MeV data show smooth energy dependence.

KVIA ｘｘ

Aｙｙ

AｙｙAxx

Ayy & Axx measured

Only Ayy measured

Present data RCNP

Energy dependence of Axx (90) and Ayy (90)

Summary

・ Axx and Ayy of pd-capture reaction at Ed=137,196 MeV were measured. ・ Measured Axx largely disagrees with calculations, and 23NF can not explain the difference.

・ Data shows Axx ～ Ayy whereas Axx≠Ayy in calculation. The relation Axx ~ Ayy may be a possible signature of short-range force (3NF).

・ RCNP data and KVI data disagree in the absolute values.

A new experiment on Azz at 196 MeV

will be made in October 2006 (5days later).

Present data at 137MeVKVI dataAV18AV18+URBIX

●●

- - -―

(PRB617,2005,18) at 133MeV

Axx at RCNP(137MeV) and at 133 MeV (KVI)

present dataKVI dataAV18AV18+URBIX

●●

- - -―

Ayy at RCNP(137MeV) and at 133 MeV (KVI)

(PRB617,2005,18) at 133MeV