Development of axial asymmetry in the neutron-rich nucleus Mo-110

作者：Watanabe, H.^*; Yamaguchi, K.; Odahara, A.; Sumikama, T.; Nishimura, S.; Yoshinaga, K.; Li, Z.; Miyashita, Y.; Sato, K.; Prochniak, L.; Baba, H.; Berryman, J. S.; Blasi, N.; Bracco, A.; Camera, F.; Chiba, J.; Doornenbal, P.; Go, S.; Hashimoto, T.; Hayakawa, S.; Hinke, C.; Hinohara, N.; Ideguchi, E.; Isobe, T.; Ito, Y.; Jenkins, D. G.; Kawada, Y.; Kobayashi, N.; Kondo, Y.; Kruecken, R.; Kubono, S.; Lorusso, G.; Nakano, T.; Nakatsukasa, T.; Kurata-Nishimura, M.; Ong, H. J.; Ota, S.

来源：Physics Letters B, 2011, 704(4): 270-275.

DOI：10.1016/j.physletb.2011.09.050

• Mo-110
• Axial asymmetry
• Nuclear-shape transitions

The neutron-rich nucleus Mo-110 has been investigated by means of gamma-ray spectroscopy following the beta-decay of Nb-110, produced using in-flight fission of a U-238 beam at 345 MeV/nucleon at the RIBF facility. In addition to the ground-band members reported previously, spectroscopic information on the low-lying levels of the quasi-gamma band built on the second 2( ) state at 494 key has been obtained for the first time. The experimental finding of the second 2( ) state being lower than the yrast 4( ) level suggests that axially-asymmetric gamma softness is substantially enhanced in this nucleus. The experimental results are compared with model calculations based on the general Bohr Hamiltonian method. The systematics of the low-lying levels in even-even A approximate to 110 nuclei is discussed in comparison with that in the neutron-rich A approximate to 190 region, by introducing the quantity E-S/E(2(1)( )), E-S = E(2(2)( )) - E(4(1)( )), as a global signature of the structural evolution involving axial asymmetry.

• 出版日期2011-10-19
• 单位RIKEN