Beta-decay of neutron-rich Ni and Cu isotopes in a shell model approach

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Beta-decay of neutron-rich Ni and Cu
isotopes in a shell model
approach

• Alexander Lisetskiy

Hirschegg 2006
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Exotic regions
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Shell Model Effective Interaction
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Fitting Landscape

• F. Lisetskiy, B. A. Brown,
• M. Horoi, H. Grawe,
• PRC 70, 044314, (2004)

• Ni Cu isotopes
• N49,48 isotones

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Nuclear structure phenomena near 78Ni

• No seniority isomers in 72Ni and 74Ni
• No high-spin isomers in 73Cu,75Cu and 77Cu
• No 8 isomers in 72Zn,74Zn,76Zn
• 5/2- ground state in 75Cu,77Cu and 79Cu
• Pseudo-magicity of 68Ni

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Theoretical tools for beta-decay studies
Global picture Finite Range Droplet Model
QRPA (P. Moeller, K. L. Kratz)
Self-consistent HF-BCS continium QRPA (I.
Borzov, S. Fayans) Local picture Shell Model
with effective interactions Unified picture for
many different properties of particular nucleus
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Model Space
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beta-decay scheme
Sn neutron separation energy Pn branching of
beta delayed neutron emission
Importance! Sn
for r-process path Pn abundance
pattern T1/2 timescale, abundance
pattern
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Ni beta-decay Energetics
Qb(A,Z) M(A,Z) - M(A,Z1)
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Ni beta-decay Energetics
Sn(A,Z) B(A,Z) - B(A-1,Z)
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Ni beta-decay Half-lives
P. T. Hosmer et al., PRL 94, 112501 (2005)
Quenching for Gamow -Teller operator
q0.37! Common q value is 0.70-0.75
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Ni beta-decay Half-lives
Quenching factor is Q-value dependent
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Ni beta-decay beta-delayed n-emission
H. Schatz, in prep. (MSU data)
Pn GT branching for states with Qb gt Eexc gt Sn
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Cu beta-decay Energetics
Qb(A,Z) M(A,Z) - M(A,Z1)
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Cu beta-decay Energetics
Sn(A,Z) B(A,Z) - B(A-1,Z)
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Cu beta-decay Half-lives
P. T. Hosmer et al., PRL 94, 112501 (2005)
Quenching for Gamow -Teller operator
q0.37! Common q value is 0.70-0.75
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Cu beta-decay Half-lives
Quenching factor is Q-value dependent
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Cu beta-decay beta-delayed n-emission
H. Schatz, in prep. (MSU data)
Pn GT branching for states with Qb gt Eexc gt Sn
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75Ni B(GT) distribution
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78Ni beta-decay
x10
f7/2 included
f7/2 included
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Summary Outlook

• Improved shell model effective interaction
• for the p3/2p1/2f5/2g9/2 space in action
• Self-consistent good description of beta-decay
• data for Ni and Cu isotopes
• Strong quenching of GT strength origin ?
• Large-scale shell model calculations
• Tests for Zn and Ga beta-decay
• rp-process nuclei 64Ge, 68Se
• Role of first forbidden transitions

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Collaborators
Alex Brown, NSCL, MSU Mihai Horoi, CMU Hendrik
Schatz, JINA, NSCL, MSU GSI K. Langanke G.
Matrinez-Pinedo