Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag

• Published in: Physics letters. B Vol. 823; no. C; p. 136766
• Main Authors: Watanabe, H., Yuan, C.X., Lorusso, G., Nishimura, S., Xu, Z.Y., Sumikama, T., Söderström, P.-A., Doornenbal, P., Browne, F., Gey, G., Jung, H.S., Taprogge, J., Vajta, Zs, Wang, H.K., Wu, J., Yagi, A., Baba, H., Benzoni, G., Chae, K.Y., Crespi, F.C.L., Fukuda, N., Gernhäuser, R., Inabe, N., Isobe, T., Jungclaus, A., Kameda, D., Kim, G.D., Kim, Y.K., Kojouharov, I., Kondev, F.G., Kubo, T., Kurz, N., Kwon, Y.K., Lane, G.J., Li, Z., Moon, C.-B., Montaner-Pizá, A., Moschner, K., Naqvi, F., Niikura, M., Nishibata, H., Nishimura, D., Odahara, A., Orlandi, R., Patel, Z., Podolyák, Zs, Sakurai, H., Schaffner, H., Simpson, G.S., Steiger, K., Suzuki, H., Takeda, H., Wendt, A., Yoshinaga, K.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2021; Elsevier
• Subjects: 127Ag; Gamow-Teller β decay; Isomer; Radioactive isotope beam; Shell evolution; Shell evolution; Gamow-Teller β decay; Radioactive isotope beam; 127Ag; Isomer
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2021.136766

The change of the shell structure in atomic nuclei, so-called “nuclear shell evolution”, occurs due to changes of major configurations through particle-hole excitations inside one nucleus, as well as due to variation of the number of constituent protons or neutrons. We have investigated how the shell evolution affects Gamow-Teller (GT) transitions that dominate the β decay in the region below 132Sn using the newly obtained experimental data on a long-lived isomer in 127Ag. The T1/2=67.5(9) ms isomer has been identified with a spin and parity of (27/2+) at an excitation energy of 1942−20+14 keV, and found to decay via an internal transition of an E3 character, which competes with the dominant β-decay branches towards the high-spin states in 127Cd. The underlying mechanism of a strong GT transition from the 127Ag isomer is discussed in terms of configuration-dependent optimization of the effective single-particle energies in the framework of a shell-model approach.