Beta decay and Structure of Exotic Nuclei near 78Ni

Alexander Lisetskiy

NSCL,JINA,MSU

Motivation

• Astrophysical r-process

• Recent experimental progress for neutron-rich nuclei • Lack of shell model effective interactions for exotic regions

Where are exotic nuclei?

Shell Model Effective Interaction

T=1 interaction and SPE sources

Ni isotopes +N=50 isotones

G-matrix Bonn-Cpotential

56Ni core

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

Single particle energies

5757NiNi 7777NiNi 7979CuCu 9999InIn

p3/2

f5/2

g9/2

p1/2

g9/2

-1

p1/2-1

f5/2-1

p3/2-1

f5/2-1

p3/2-1

p1/2-1

g9/2

-1

g9/2

p1/2

f5/2

p3/2

Cu: spectra and magnetic moments

A.F. Lisetskiy, B. A. Brown, M. Horoi, EPJ direct (2005)

L. Weissman & U. Koester,Private communication

Ni: Beta-decay properties

75Ni and 78Ni: B(GT) distribution

T=0 interaction and SPE modifications

Cu isotopes + N=49,48 isotones

jp = jn + jn’Vmon(jp,jn’)

New Single Particle Energies

5757NiNi 7777NiNi 7979CuCu 9999InIn

p3/2

f5/2

g9/2

p1/2

g9/2

-1

p1/2-1

f5/2-1

p3/2-1

f5/2-1

p3/2-1

p1/2-1

g9/2

-1

g9/2

p1/2

f5/2

p3/2

Ni: New Beta-decay results

P. T. Hosmer et al., PRL 94, 112501 (2005)

75Ni: New B(GT) distribution

Old results

New results

76Ni: New B(GT) distribution

Old results

New results

78Ni: Microscopic structure of GT strength distribution

Cu isotopes

P. T. Hosmer, in preparation …

Summary

• Improved shell model effective interaction for the p3/2p1/2f5/2g9/2 space in action

• Good agreement between theory and experiment for Ni isotopes indicates reliability of the interaction

• Good description of T1/2 and Pn values for Cu isotopes

• Beta decay data provide important information where nuclear structure data are missing

• Extended studies of Cu, Zn, Ga, Ge