Proton Shell Evolution below Sn-132: First Measurement of Low-Lying beta-Emitting Isomers in Ag-123,Ag-325

Chen, Z. Q.; Li, Z. H.; Hua, H.; Watanabe, H.; Yuan, C. X.; Zhang, S. Q.; Lorusso, G.; Nishimura, S.; Baba, H.; Browne, F.; Benzoni, G.; Chae, K. Y.; Crespi, F. C. L.; Doornenbal, P.; Fukuda, N.; Gey, G.; Gernhaeuser, R.; Inabe, N.; Isobe, T.; Jiang, D. X.; Jungclaus, A.; Jung, H. S.; Jin, Y.; Kameda, D.; Kim, G. D.; Kim, Y. K.; Kojouharov, I.; Kondev, F. G.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Li, X. Q.; Lou, J. L.; Lane, G. J.; Li, C. G.; Luo, D. W.; Montaner-Piza, A.; Moschner, K.; Niu, C. Y.; Naqvi, F.; Niikura, M.; Nishibata, H.; Odahara, A.; Orlandi, R.; Patel, Z.; Podolyak, Zs.; Sumikama, T.; Soderstrom, P. -A.; Sakurai, H.; Schaffner, H.; Simpson, G. S.; Steiger, K.; Suzuki, H.; Taprogge, J.; Takeda, H.; Vajta, Zs.; Wang, H. K.; Wu, J.; Wendt, A.; Wang, C. G.; Wu, H. Y.; Wang, X.; Wu, C. G.; Xu, C.; Xu, Z. Y.; Yagi, A.; Ye, Y. L.; Yoshinaga, K.     «

Chen, Z. Q.; Li, Z. H.; Hua, H.; Watanabe, H.; Yuan, C. X.; Zhang, S. Q.; Lorusso, G.; Nishimura, S.; Baba, H.; Browne, F.; Benzoni, G.; Chae, K. Y.; Crespi, F. C. L.; Doornenbal, P.; Fukuda, N.; Gey, G.; Gernhaeuser, R.; Inabe, N.; Isobe, T.; Jiang, D. X.; Jungclaus, A.; Jung, H. S.; Jin, Y.; Kameda, D.; Kim, G. D.; Kim, Y. K.; Kojouharov, I.; Kondev, F. G.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Li, X. Q.; Lou, J. L.; Lane, G. J.; Li, C. G.; Luo, D. W.; Montaner-Piza, A.; Moschner, K.; Niu, C. Y.; N...     »

The beta-delayed gamma-ray spectroscopy of neutron-rich Ag-123,Ag-325 isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2(-) beta-emitting isomers in Ag-123,Ag-325 are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2(+) and 1/2(-) levels is extended in Ag isotopes up to N = 78, providing a clear signal for the reduction of the Z = 40 subshell gap in Ag towards N = 82. Shell-model calculations with the state-of-the-art V-MU plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in Ag-123,Ag-325. The tensor force is found to play a crucial role in the evolution of the size of the Z = 40 subshell gap. The observed inversion of the single-particle levels around Ag-123 can be well interpreted in terms of the monopole shift of the pi 1g(9/2) orbitals mainly caused by the increasing occupation of nu 1h(11/2) orbitals.     «

The beta-delayed gamma-ray spectroscopy of neutron-rich Ag-123,Ag-325 isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2(-) beta-emitting isomers in Ag-123,Ag-325 are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2(+) and 1/2(-) levels is extended in Ag isotopes up to N = 78, providing a clear signal for the reduction of the Z = 40 subshell gap in Ag towards N = 82....     »