Diapositive 1

1
N28, Shell Closure and Shapes
L. Gaudefroy CEA/DIF Bruyères-le-Châtel
Courtesy of M. Rejmund
LIA EFES Workshop GANIL 2-4 March 2009
2
N28

• 1st magic number originating from SO interaction
• -Evolution of SO with isospin
• -Role of pn interaction on structure

fp
Without SO interaction
sd
3
N28
Agreement on the reduction of N28 in exotic
nuclei
4
N28
Progressive decrease of E(21) at N28
5
In this talk
Ar
Ca
S
Si
Def.
Spher.
Part I Transfer reactions at
Z18 -46Ar28(d,p) 44Ar26(d,p) Part II
Magnetic moment at Z16 -Study of 43mS27.
6
(d,p) reaction Principle
Study of the fp single particle states at N28
(d,p) transfer reaction
f5/2
p1/2
p3/2
28
f7/2
46Ar28
47Ar29
7
46Ar(d,p)47Ar Résults

• New Mass excess for 47Ar
• Dm(47Ar)-25.20(8)MeV
• before -25.9(1)MeV
• Sn 3.55(8) MeV
• Before 4.3 MeV

Unknown Spectroscopy
8
Results 46Ar
3.3
0.43
2.7
0.22
46Ar N28 eroded gt Correlations in the GS of
46Ar
1.1
0.81
0
GS
0.61
46Ar
f7/2
d3/2
gs
s1/2
d5/2
p
n
Shell Structure
L. Gaudefroy, O. Sorlin et al., PRL 97, 092501
(2006)
9
44Ar(d,p)45Ar Results
10
47Ca27 45Ar27 Shell Model
ANTOINE code E. Caurier F. Nowacki - Strasbourg
11
N27 isotones
43S 3/2 7/2 Inversion suggested in F. Sarazin
et al. PRL 84, 5062 (2000)
L. Gaudefroy et al., PRC 78, 034307 (2007)
12
g-factor measurement in 43S
-Mass measurement at GANIL F. Sarazin et al. PRL
84, 5062 (2000) gt Low lying isomeric state
SM-based interpretation
g factor of the isomeric state -Direct
determination of spin/parity. -Test the wave
function.
13
Principle
Fragmentation 300 43S/sec
LISE_at_GANIL
14
Results
15
Experiment vs. Theories
-K1/2 decoupled band.
GS deformed band b0.30 7/2- (isom.) not in
this band Rather spherical
Code ANTOINE Caurier Nowacki - Strasbourg
16
Experiment vs. Theories
Mean Field -HFB Gogny D1S -Blocking -GCM
GOA
Ground State -K1/2 (from p3/2) -b0.37 -Decou
pling parameter Inertia parametergt in
agreement with PR
States from f7/2 orbit -Within 400keV -Around
b0
L. Gaudefroy, J.M. Daugas et al, PRL 102,092501
(2009)
17
Conclusion
Part I 44Ar(d,p), 46Ar(d,p) -Correlations
present in the N28 nucleus 46Ar. -SM
description of N27 isotones showing the
evolution of multipolar energy. Part II
g-factor of 43mS -Direct evidence of the
inversion of the 7/2- - 3/2- states -Successfull
y interpreted with 3 models -Deformed ground
state K1/2 band -Rather spherical isomeric
state
18
Collaboration
France CEA-Bruyères-le-châtel, IPNO, GANIL,
CEA-Saclay, CSNSM, CENBG, IReS, LPSC Bulgaria
Faculty of Physics Germany Universität
Mainz Hungary INR Israel Weizmann
Institute Japan Riken USA FSU Russia
FLNR/JINR
19
(No Transcript)
20
44Ar(d,p)45Ar Exp. vs Theorie
45Ar27
Satisfactory agreement
21
More exotic N27 isotones
L. Gaudefroy et al. PRC 78, 034307 (2007)