New Island of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="italic">μ</mi><mi>s</mi></math> Isomers in Neutron-Rich Nuclei around the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="italic">Z</mi><mspace></mspace><mo>=</mo><mspace></mspace><mn>28</mn><mn></mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="italic">N</mi><mspace></mspace><mo>=</mo><mspace></mspace><mn>40</mn><mn></mn></math> Shell Closures

R. Grzywacz; R. Béraud; C. Borcea; A. Emsallem; M. Glogowski; H. Grawe; D. Guillemaud-Mueller; M. Hjorth-Jensen; M. Houry; M. Lewitowicz; A. C. Mueller; A. Nowak; A. Płochocki; M. Pfützner; K. Rykaczewski; M. G. Saint-Laurent; J. E. Sauvestre; M. Schaefer; O. Sorlin; J. Szerypo; W. Trinder; S. Viteritti; J. Winfield

doi:10.1103/PhysRevLett.81.766

New Island of $μ s$ Isomers in Neutron-Rich Nuclei around the $Z = 28$ and $N = 40$ Shell Closures

R. Grzywacz, R. Béraud, C. Borcea, A. Emsallem, M. Glogowski, H. Grawe, D. Guillemaud-Mueller, M. Hjorth-Jensen, M. Houry, M. Lewitowicz, A. C. Mueller, A. Nowak, A. Płochocki, M. Pfützner, K. Rykaczewski, M. G. Saint-Laurent, J. E. Sauvestre, M. Schaefer, O. Sorlin, J. Szerypo, W. Trinder, S. Viteritti, and J. Winfield

Phys. Rev. Lett. 81, 766 – Published 27 July 1998

Abstract

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 $60.3 A$ MeV $^{86} Kr$ beam on a $^{nat} Ni$ 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 $g_{9 / 2}$ orbital, an intruder level in the $N = 3$ $fp$ shell. It is illustrated with the decay properties of $^{69} {Ni}^{m}$ , $^{70} {Ni}^{m}$ , and $^{71} {Cu}^{m}$ interpreted within the nuclear shell model.