학술논문
Isomeric states in neutron-rich nuclei around $N = 40$
Document Type
Working Paper
Author
Wimmer, K.; Recchia, F.; Lenzi, S. M.; Riccetto, S.; Davinson, T.; Estrade, A.; Griffin, C. J.; Nishimura, S.; Phong, V.; Söderström, P. -A.; Aktas, O.; Al-Aqeel, M.; Ando, T.; Baba, H.; Bae, S.; Choi, S.; Doornenbal, P.; Ha, J.; Harkness-Brennan, L.; Isobe, T.; John, P. R.; Kahl, D.; Kiss, G.; Kojouharov, I.; Kurz, N.; Labiche, M.; Matsui, K.; Momiyama, S.; Napoli, D. R.; Niikura, M.; Nita, C.; Saito, Y.; Sakurai, H.; Schaffner, H.; Schrock, P.; Stahl, C.; Sumikama, T.; Werner, V.; Witt, W.; Woods, P. J.
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Subject
Language
Abstract
Neutron-rich nuclei in the vicinity of the $N=40$ island of inversion are characterized by shell evolution and exhibit deformed ground states. In several nuclei isomeric states have been observed and attributed to excitations to the intruder neutron $1g_{9/2}$ orbital. In the present study we searched for isomeric states in nuclei around $N=40$, $Z=22$ produced by projectile fragmentation at RIBF. Delayed $\gamma$ rays were detected by the EURICA germanium detector array. High statistics data allowed for an updated decay scheme of $^{60}$V. The lifetime of an isomeric state in $^{64}$V was measured for the first time in the present experiment. A previously unobserved isomeric state was discovered in $^{58}$Sc. The measured lifetime suggests a parity changing transition, originating from an odd number of neutrons in the $1g_{9/2}$ orbital. The nature of the isomeric state in $^{58}$Sc is thus different from isomers in the less exotic V and Sc nuclei.
Comment: PRC accepted
Comment: PRC accepted