New island of $\mu$s-isomers in neutron-rich nuclei around the Z=28 and N=40 shell closures

R. Grzywacz , R. Béraud (1) , C. Borcea , A. Emsallem (1) , M. Glogowski , H. Grawe , D. Guillemaud-Mueller (2) , M. Hjorth-Jensen , M. Houry , M. Lewitowicz (3) , a C. Mueller , A. Plochocki , M. Pfutzner , K. Rykaczewski , M.G. Saint-Laurent (3) , J E. Sauvestre , O. Sorlin (2) , J. Szerypo , W. Trinder , S. Viteritti (1) , J. Winfield

1 IPNL - Institut de Physique Nucléaire de Lyon
2 IPNO - Institut de Physique Nucléaire d'Orsay
3 GANIL - Grand Accélérateur National d'Ions Lourds

New isomeric states in the neutron-rich nuclei near the Z=28 and N=40 shell closures have been identified among the reaction products of a 60.3A MeV 86Kr beam on a natNi target. From the measured isomeric decay properties information about the excited states and their nuclear structure has been obtained. The isomerism is related mostly to the occupation of the neutron g9/2 orbital, an intruder level in the N=3 fp shell. It is illustrated with the decay properties of 69Nim, 70Nim, and 71Cum interpreted within the nuclear shell model.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

R. Grzywacz, R. Béraud, C. Borcea, A. Emsallem, M. Glogowski, et al.. New island of $\mu$s-isomers in neutron-rich nuclei around the Z=28 and N=40 shell closures. Physical Review Letters, 1998, 81, pp.766-769. ⟨10.1103/PhysRevLett.81.766⟩. ⟨in2p3-00012078⟩