Exotic Nuclei and Neutron Stars

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Exotic Nuclei and Neutron Stars Meeting, Orsay
September 2006 Giant Resonances H.J.
Wörtche
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Issues of Relevance for Neutron Stars

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• issues accessible via GRs
• bulk properties of asymmetric (N/Z) matter
• compressibility (isoscalar monopole, isoscalar
  dipole)
• symmetry energy (isovector modes)
• neutron skin (spin-dipole)

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• issues accessible via GRs
• pion field / pion condensate
• (Auerbach, Toki)
• Jp 0- component spin-dipole resonance

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• issues accessible via GRs (?)
• super giant resonances in Wigner cells
• (Khan, Sandulescu, Van Giai)
• systematics of E0, E1, E2 resonances in
  neutron-rich nuclei

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• issues accessible via GRs
• related issues
• - propagation nuclear processing, propagation
  of
• ultra-high energetic nuclear ejectiles
• GT and spin-dipole resonance
• (?p process, Fröhlich/Martinez-Pinedo, PRL 96
  142502 !!!)
• isovector E1 Giant Dipole resonance
• Pygmy (low-energy flank Giant Dipole)

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Illustrative Examples for Stable Nuclei

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• examples for stable nuclei
• bulk properties of asymmetric (N/Z) matter
• compressibility (isoscalar monopole, isoscalar
  dipole)
• symmetry energy (isovector modes)
• neutron skin (spin-dipole)

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single arm spectra 116Sn ISGDR resonant
structure Ex 20 - 25 MeV superimposed nuclear
instrumental continuum overlap with HEOR
KVI - (?,?n)
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KVI - (?,?n) comparison with theory
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• examples for stable nuclei
• related issues
• e--capture in supernova progenitor
• GT and spin-dipole resonance
• (?p process, Fröhlich/Martinez-Pined, PRL 96
  142502 !!!)
• isovector E1 Giant Dipole resonance
• Pygmy (low-energy flank Giant Dipole)

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58Ni, GT strengths comparison(n, p), (d, 2He),
theory

• up to 4 MeV excitation
• 13 GT transitions measured (d, 2He)
• strength rebinned in 1 MeV bins
• experimental significant differences
• updated shell model calculations by
• Pinedo/Langanke

Pinedo/Langanke Caurier et al.
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58Ni comparison of e-capture rates
theory/experiment

• rates vary up to a factor 5 - 6
• FFN not too far off
• large scale shell-model
• calculations fail at low T
• calculations with improved
• residual interaction fit

(n,p)
FFN
Pinedo, Langanke
Caurier et al.
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Speciality for Exotic Beams _at_ SPIRAL2 Low-Lying
Collective Modes in Neutron-Rich Nuclei (to
Extrapolate the Physics of Wigner Cells)

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• low-lying collective modes
• (very) neutron rich nuclei a laboratory (?) for
  Wigner cells
• systematic studies of
• location/width/transition strength of E0,E1,E2
  modes
• (excitation with photons and alphas (protons))
• ph - structure of the modes
• (neutron decay)
• neutron pairing
• (e.g. (p,t) in inverse kinematics)

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single arm spectra 116Sn ISGDR resonant
structure Ex 20 - 25 MeV superimposed nuclear
instrumental continuum overlap with HEOR
KVI - (?,?n)
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gated final-state spectra 90Zr, 116Sn,
208Pb Ef.s. Ex - Sn- En(-Erecoil ) extracted
under conditon ? cut on continuum ? cut on
resonant region
KVI - (?,?n)
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theory M.L. Gorelik, I.V. Safonov, M.H.
Urin Phys. Rev. C69 (2004) 054322
good agreement for 208Pb theory overshoots
experiment for 90Zr and 116Sn
KVI - (?,?n) comparison with theory
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