Diapositive 1

1
Captures and Molecules
Sandrine Courtin Institut Pluridisciplinaire
Hubert Curien, Département des Recherches
Subatomiques and Université Strasbourg I
2
Now
11.8
82
126
50
AME03-LMD, P. Van Isacker et A.E.L. Dieperink,
Int. J Mod. Phys. E15,1371(2006)
82
28
50
20
-9.32
8
28
8
20
N-rich around N 20 28 How ?
Transfer reactions ? transfer process /
nucleon-nucleon ?
spectroscopy Ex 40Ar
(ELab 255 MeV) 208Pb (11/2007)
n-rich Ar Where ?
Legnaro (Prisma-Clara), GANIL Collaboration
IPHC, Univ. Zagreb (S. Szilner et al.),
Univ. Torino, LNL Legnaro
(L. Corradi et al.), Univ. of West
Scotland (R. Chapman et al.) Theory
G. Pollarolo (Univ. Torino), E. Caurier, F.
Nowacki (IPHC)
3
Now
(12C
- 12C) resonances in 24Mg
(12C -
16O) resonances in 28Si
Molecules ? Deformation ?
g-decay
Radiative Capture Reactions
recent results
Clustering in light heavy-ions How ?
Narrow molecular resonances, fragment,
particle, g decay Ex
(24Mg-24Mg) resonances in 48Cr (12C
- 12C) resonances in 24Mg (12C -
16O) resonances in 28Si Where ?
Legnaro (Prisma-Clara), Berkeley (Gammasphere),
Triumf (Dragon BGO),
Argonne (GammasphereFMA) Collaboration IPHC,
Univ. York (D. Jenkins et al.), Triumf (D.
Hutcheon et al.) ANL (C. Lister et
al.), Univ. of West Scotland (R. Chapman et
al.) Theory J. Dudek (IPHC), K.
Pomorski (Lublin) LSD Model
S. Ohkubo. K. Yamashita (Univ. Kochi) aCM
D. Baye and P.
Descouvemont (ULB) GCM
J. Cseh and G. Lévaì (Atomki, Debrecen) ACM
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12C(12C,g)24Mg and 12C(16O,g)28Si Setting the
stage
Resonances ? NOC (F. Haas and Y. Abe, Phys. Rev.
Lett. 46 (1981) 1667)
Narrow Resonances (150 keV), DEDt h ? molecules

Radiative Capture Light Particles vs
Heavy-Ions

• Light heavy-ions
• 12C12C ? 24Mg, 12C16O ? 28Si
• Sandorfi et al. (BNL, 1980)
• Narrow resonances _at_ Bc
• No recoil, decay to g.s.

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Results on 12C(12C,g)24Mg and 12C(16O,g)28Si
Measurements ON- and OFF resonance _at_ BC
First Stage
D.A. Hutcheon et al., NIM A 498, 190 (2003).
Second Stage

• ISAC I RNBs / Stable (OLIS)
• 0 spectrometer
• Tof on 17 m
• Beam rejection 1013
• Acceptance cone half angle 20 mrad

• gas/solid target system
• recoil detectors (DSSSD, )
• BGO array (? 50 _at_ 5 MeV)

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Results on 12C(12C,g)24Mg and 12C(16O,g)28Si
14 MeV
10 MeV
12C16O Highest energy ?-ray
12C12C Highest energy ?-ray
S. C. et al., Fusion 06, San Servolo, AIP Conf.
Proc. 853 (2006), S. C. et al., Journal of
Physics G, London (2008).
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Clusters ?
? Shell Model ? 16O, doubly magic , 02, 2, 4
B(E2) (2?0) 27 W.u., B(E2) (4 ? 2) 65
W.u. 8Be, 9Be, 10Be 12C (0, Hoyle) Model Space

? Cluster Models ? CM (Abe Uegaki), ex
24Mg-24Mg resonances in 48Cr. GCM, (Baye
Descouvemont), deformed structures, rotational
bands.
? AMD ? Ab initio (Horiuchi, Kanada Enyo) 24Mg,
28Si, 32S, 36Ar, 40Ca, 28Mg Deformed structures,
SD, clusters Clusters in n-rich nuclei
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Results on 12C(12C,g)24Mg and 12C(16O,g)28Si Theor
y
What is the structure of those states ?
24Mg(12C-12C) P. Descouvemont and D. Baye,
Phys.Lett. 169 B (1986) 143.
28Si(12C-160) Ohkubo and Yamashita, Phys.Lett. B
578 (2004) 304.
? Links between low-lying members of these
cluster bands ?
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Results on 12C(12C,g)24Mg and 12C(16O,g)28Si
2 resonance ? (Ecm 6 MeV)
12C12C
simulation
12C16O
experiment
D.G. Jenkins, S. Courtin et al., Phys. Rev. C (in
press)

• Resonances strongly correlated to 24Mg and 28Si
  states
• Large part of the flux via doorway states around
  10-11 MeV.
• (a threshold 9.3 MeV and 10.0 MeV)

• 2 scenarii
• 1- States with a specific structure ?
• 2- Decay via T 1 states through DT 1 M1
  allowed transitions may be
• favoured in this N Z nucleus

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Lower energies ? What happens below BC and down
to Eastro ?
? Medium mass systems fusion X-sections,
hindrance Ex 64Ni 64Ni,
incompressibility, CC calc.
36S48Ca, LNL, Legnaro, 10/2007 (20 below
BC) ? 12C 12C, 12C 16O C.L. Liang, K.E.
Rehm, B.B. Back and R.V.F. Janssens, PRC 75,
015803 (2007), 16O and 12C induced fusion. S
extrapolated to low energies ? 12C(a,g) 16O
Reaction rate, s 0.01 fb _at_ EGamow
Direct kin. (Stuttgart, M. Assuncao et al., PRC
73 (2006) 055801), no recoil Inverse kin.
(Triumf, C. Matei et al. PRL 97 (2006) 242503)
recoil with Dragon, new path
E
12C(a,g) 16O, Dragon data
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Next move
Identify the doorway states Giant resonances
molecular resonances ? N-rich clusters ? ? new
generation of scintillators (LaBr3(Ce))
state-of-the-art spectro
Shell model and mean field, a kind of unified
view
TDHF, reaction mechanism at Bc and below as a
function of the reacting time
12C 12C, why ?
E
12
12C16O et 12C12C
Breakup reactions 28Si ? 12C16O, 24Mg ? 12C12C
RC
RC

• 12C16O breakup states to 45 MeV. C.J. Metelko
  et al., J. Phys. G29 (2003), 697
• Reaction 12C(20Ne,12C16O)???_at_ ANL

• 12C12C breakup states to 50 MeV C.J. Metelko
  et al., Phys.Rev. C68 (2003)
• 0544321
• Reaction 12C(16O,12C12C)?

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Multinucleon transfer, far from stability
(collab. L. Corradi, LNL) ? n-pairs transfers in
n-rich nuclei ? sfus very _at_ low E.
SPIRAL2

Nuclear Molecules ? resonances and doorway
states GammasphereFMA, AGATA, PARIS

SPIRAL 2
24 Si detectors _at_ 45 highly efficient g-array