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Pionic fusion: comparison of different spin/isospin channels. Study coherence of pion production, role of clustering correlations in the pionic fusion process, production mechanism: s, p-wave dynamics. Existing data and models. semi-phenomenological model: - PowerPoint PPT Presentation
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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.