Spin Correlation Parameter Cyy of p + 3He Elastic Backward

Scattering at Intermediate Energy

Youhei Shimizu

RCNP, Osaka University

CollaboratorsCollaboratorsRCNP, Osaka University : Y. Shimizu, K. Hatanaka, Y. Sakemi, A. Tamii, H.P. Yoshida, M. Uchida, Y. Shimbara, K. Fujita, Y. Tameshige, H. matsubara

CNS, University of Tokyo : T. Uesaka, T. Wakui, T. Kawabata, Y. Sasamoto

Saitama University : K. Itoh

Kyushu University : K. Sagara, T. Wakasa, T. Kudoh, M. Tomiyama, H. Ohira

Osaka University : T. Adachi

Tohoku University : H. Okamura

RIKEN : H. Ueno, K. Suda

Contents1. Introduction 1.1. Few Body System

1.2. Elastic Backward Scattering

2. Experimental Setup 2.1. RCNP Ring Cyclotron Facility

2.2. Polarized 3He Target

3. Results 3.1. Calibration of 3He Polarization

3.2. p+3He Elastic Backward Scattering

3.3. Comparison with Theoretical Prediction

4. Summary

Introduction

2NF only with 3NF Exp.

7.953 8.483 8.482

Few body system

Triton binding energy (MeV)

Some problems in the spin structure of 3NF

p+d Elastic Scattering

K. Hatanaka et al., PRC 44, 44002 (2002)

d+p Break-up Reactiond+p Capture Reaction......

Elastic Backward Scattering (EBS)

• Elastic Backward Scattering (EBS)

• Spin Correlation Parameter Cyy

Structure of the lightest nuclei (d, 3He, ) at short distances between the constituent nucleons

high momentum componentsof the target wave function

target-related spin observable is sensitive tothe spin-dependent parts of the target wave function

p + 3He EBS at RCNP

Experimental Condition

• Beam : Polarized proton 200, 300, 400 MeV

10 40 nA, polarization 70 • Target : Polarized 3He gas target

polarization 10 • Angle : 0 degrees

• Solid angle : 2.8 msr

• Reaction : 3He(p,+)4He 3He(p,3He)p

• Observables : 3He polarization

d/d, Cyy

Experimental SetupOverview of theOverview of theRCNP Ring Cyclotron FacilityRCNP Ring Cyclotron FacilityOverview of theOverview of theRCNP Ring Cyclotron FacilityRCNP Ring Cyclotron Facility

Grand RaidenGrand RaidenGrand RaidenGrand Raiden

D1 Faraday CupD1 Faraday Cup

The Schematic view of the Polarized 3He Target

Density : 8.96e+19 cm-3

Max Polarization : 19 %

Measurement of 3He Polarization

• AFP (Adiabatic Fast Passage) - NMR

• 3He(p,+)4He

Monitor throughout the experimentNMR signal is proportional to the amount of polarization.Need to be calibrated by another method.

Calibration by using polarized proton beam

002

1

2

1 1yyC

Very Preliminary

Very Preliminary

3He(p,+)4He

NMR2

He 1016.062.6 VP NMR2

He 1016.062.6 VP

Relation to AFP-NMR Amp.

R

R

pP

y

1

11beamHe

II

IIR beam

targetI

K.M. Furutani et al., PRC 50, 1561(1994)

Very Preliminary

Very Preliminary

p+3He Elastic Backward Scattering

Cross Section is consistent with other experimental data. New data for spin correlation parameter Cyy

Cross Section is consistent with other experimental data. New data for spin correlation parameter Cyy

Comparison with Theoretical Prediction

• For Cyy, there are large discrepancy

PI

DIR

ODE+PI+DIR

2N+PI

Calculated by A.P. Kobushkin

Reaction Mechanism• One-Deuteron-Exchange

d d or d*

Ep < ~200 MeV

• rescattering of the intermediate PIon off the intermediate deuteron

200 MeV < Ep < 1000 MeV

• DIRect proton interaction

Ep > 1000 MeV

p (m, p)

3He (M, P)

3He (M’, P’)

p (m’, p’)

d or d*

p (m, p) 3He (M’, P’)

3He (M, P) p (m’, p’)

p (m, l)~

p (m’, l’)~

d (’, p’d)

d (, pd) (q)

(q’)

d or d*3He (M, P) 3He (M’, P’)

p (m, p) p (m’, p’)

p (m1, l) p (m’1, l’)

Contribution of the Singlet Deuteron

• ODE (Ep < ~ 0.2 GeV)

• PI (0.2 GeV < Ep < 1 GeV)

• DIR (Ep > 1 GeV)

For pure deuteron exchange,Cyy =

independent on the beam energy

d d or d

(pn)sCalculated by A.P. Kobushkin

Summary

• For p+3He EBS at 200, 300, 400 MeV, d/d, Cyy were measured at RCNP.

• 3He polarization was calibrated by 3He(p,+)4He reaction.

Max Polarization : 19 %• Experimental results were compared with

existing data and theoretical predictions.

d/dconsistent with existing data

Cyy : large discrepancy with

theoretical predictions