Systematic study of isovector dipole mode up to A=50

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Systematic study ofisovector dipole modeup to
A50
KEK??????????????????? KEK, 2007?11?19?-21?
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Drip line predicted by HFB with SkM Phys. Rev.
C68, 054312.
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Nuclear Landscape
terra incognita
RIBF_at_RIKEN
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density r
neutrons
neutron skin
neutron halo
protons
radius
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Collective motion unique in unstable nuclei
Soft Dipole Mode
AMD calc., PRC71, 054602
Egg rotation?
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Motivation

• Systematic calculation of excited states
• Systematic analysis of various observables.
• Natures in stable region will change ?
• Collective motion unique in unstable nuclei
• Exist or not ?
• Which nucleus ?
• Microscopic description ?

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RPA calculationfor unstable nuclei
deformation
self-consistency
continuum
pairing
Nobody made the code including all factors
simultaneously.
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Deformation
prolate
oblate
taken from wikipedia.org.
THOHFBLNPNPwith SkM mixed pairingby M.V.
Stoitsov et al., Phys. Rev. C68, 054312.
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RPA vs. TDHFABC
16O
RPA TDHFABC
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Isovector dipole strengths up to Ca isotopes
SkM Rbox 15 fm G 1 MeV
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16O spherical
40Ca prolate
Exp. data Centre For Photonuclear Experiments
Data
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18O prolate
24Mg triaxial
Exp. data Centre For Photonuclear Experiments
Data
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Extraction of peak position and width
16O
Lorentzian Fitting
RPA Lorentzian TDHFABC
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Peak position of IVGDR
C
O
Si
S
Ar
Ca
Be
Ne
Mg
Cal. vs. Exp.
No clear relation between evolution of peak
positionand deformation.
14C
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Peak splitting by deformation
3D H.O. model
cf. Bohr-Mottelson, text book.
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Width Evolution of IVGDR
short axes long axes shperical
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Soft Dipole Mode?
pygmy
GDR
26Ne
P. Adrich et al., PRL 95, 132501
J. Gibelin, Ph. D thesis.
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Pygmy resonance in 132Sn
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Particle states in pygmy resonance
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26Ne
Exp.
SkM G 1MeV K0 K1
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Low-lying K1 state
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Particle states in low-lying K1 state
Neutron emission
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Summary

• Fully self-consistent deformed RPA calculation.
• Systematic study up to Ca isotopes.
• underestimate peak position of IVGDR.
• peak splitting by deformation.
• width evolution.
• Applied to low-lying dipole modes in 132Sn and
  26Ne.
• soft dipole mode in 132Sn.
• soft dipole mode neutron emission in 26Ne ?