13 december 2002 H.L. / KVI PAC Meeting 1

Pionic fusion: comparison of different spin/isospin channels

Studycoherence of pionproduction, role of clusteringcorrelations in thepionic fusion process, production mechanism:s, p-wave dynamics

13 december 2002 H.L. / KVI PAC Meeting 2

Existing data and modelsLiHeHe 734 ),(

L. Bimbot et al., PL B 114(82)311

semi-phenomenological model:3-nucleon transfer by p-3He reaction,analytic expressions for transfer formfactors from HO wave functions

13 december 2002 H.L. / KVI PAC Meeting 3

Interacting cluster modelKajino, Toki, Kubo, PRC 35(87)1370

correlated microscopic cluster wave functions using Resonating Group Method (RGM),NN effective interaction + Coulomb(check charge symmetry),

entrance channel distortions by local imaginary potential WD

between clusters (from DWBA)

compared toshell model wave functions

data suggest importance of cluster correlations

13 december 2002 H.L. / KVI PAC Meeting 4

origin of enhancement in cluster modeldecomposition of contributions

inter-cluster (3H – 4He) relative motionabsorbs large momentum transferto fused system 7Li

13 december 2002 H.L. / KVI PAC Meeting 5

Prediction for 0 fusion to 7Bechance to separate g.s. and 0.429 excited state:excellent application of dual-range QDC´s

simulated CM distribution with 25000 acceptedevents using cos2() distribution for pions

experiment strategy:final-state slectivity by-decay tagging

calculationsbut now data

13 december 2002 H.L. / KVI PAC Meeting 6

Inclusive d - fusionM. Andersson et al., PL B 481 (00)165

measured integrated cross section (230 nb and 140 nb at 1.2 and 1.9 MeV above threshold) and strong forward-backward asymmetry

data explained by process viaquasi-deuteron: overlap with quasi-d determines angular distribution

13 december 2002 H.L. / KVI PAC Meeting 7

Systematic study of cluster structuressimilar processes butwith increasingly complex cluster structure:decisive tool: angular distributionsfinal-state slectivity by-decay tagging

9Be

3Hen

12C*

0

10B

dd

12C*

0

6Lid 12C*

0

6Lid

4He

3Hen

7Be*

0

4He

3He

7Be*

0

?

13 december 2002 H.L. / KVI PAC Meeting 8

angle acceptance of fusion productsmax. 3.8 deg in B mode

pionic fusion

radiative fusion (capture)

ground stateexcited state (15.1 MeV)

13 december 2002 H.L. / KVI PAC Meeting 9

momentum acceptance of fusion products

array of ca. 50 phoswich detectors100 m plastic/CsI 1.3X4 cm2

in focal plane of BBSfor HI detection:fusion products of 10 – 30 A MeV

coverage of momentum distributionby HI detectors:all / accepted events

B

13 december 2002 H.L. / KVI PAC Meeting 10

Summary

)(

98

kinematicss-wavep-waves-wavep-wave

Reactions with increasing complexity in cluster structureand different pion kinematics

13 december 2002 H.L. / KVI PAC Meeting 11

acceptance of neutral pions

13 december 2002 H.L. / KVI PAC Meeting 12

TAPS schedule

ELSA Bonn - 6/03 including 2 KVI proposals

MAMI-B Mainz 6/03 - 6/04 with Crystal Barrel

KVI 7/04 - 6/05 setup during part of Trimp setup

MAMI-C 7/05 - early 07 with Crystal Barrel

13 december 2002 H.L. / KVI PAC Meeting 13

Table of BBS parameters

Mode A B Cdistance to Q1 0.84 1.14 1.44 mmomentum bite

13 19 25 %

solid angle 13.0 9.2 6.7 msrhor. angle span 4.1 3.8 3.4 deg.vert. angle span

10.3 8.0 6.4 deg.

hor. magnific. -0.46 -0.45 -0.44vert. magnific. -14.3 -10.1 -6.7lat. dispersion 2.54 2.54 2.54 cm / %ang. dispersion 42 42 42 deg.

13 december 2002 H.L. / KVI PAC Meeting 14

Proposed reactions

13 december 2002 H.L. / KVI PAC Meeting 15

design of liquid He target as buffer cryostatby Vacuum Specials Co. and P. Dendooven, J. Mulder, H. Timersma, H.L.