High- K three-quasiparticle isomers in the proton-rich nucleus Nd 129

• Published in: Physical review. C 2023-07, Vol.108 (1), Article 014317
• Main Authors: Petrache, C. M., Uusitalo, J., Briscoe, A. D., Sullivan, C. M., Joss, D. T., Tann, H., Aktas, Ö., Alayed, B., Al-Aqeel, M. A. M., Astier, A., Badran, H., Cederwall, B., Delafosse, C., Ertoprak, A., Favier, Z., Forsberg, U., Gins, W., Grahn, T., Greenlees, P. T., He, X. T., Heery, J., Hilton, J., Kalantan, S., Li, R., Jodidar, P. M., Julin, R., Juutinen, S., Leino, M., Lewis, M. C., Li, J. G., Li, Z. P., Luoma, M., Lv, B. F., McCarter, A., Nathaniel, S., Ojala, J., Page, R. D., Pakarinen, J., Papadakis, P., Parr, E., Partanen, J., Paul, E. S., Rahkila, P., Ruotsalainen, P., Sandzelius, M., Sarén, J., Smallcombe, J., Sorri, J., Szwec, S., Wang, L. J., Wang, Y., Waring, L., Xu, F. R., Zhang, J., Zhang, Z. H., Zheng, K. K., Zimba, G.
• Format: Article
• Language: English
• ISSN: 2469-9985; 2469-9993; 2469-9993
• DOI: 10.1103/PhysRevC.108.014317

Three three-quasiparticle isomers, one at an excitation energy of 2.3 MeV with T1/2=0.48(4)μs, and two shorter-lived with unknown half-lives at slightly lower energies have been identified in Nd129 using the MARA + JUROGAM 3 setup and the recoil tagging technique. All three isomers present decay patterns characteristic of high-K isomers. The known 6.7 s β-decaying isomer previously assigned to the 5/2+ level is now assigned to the new 7/2- ground state. A new low-spin 5/2+ isomeric state with a half-life of a few tens of nanoseconds has been identified, while a previously known 2.6 s β-decay activity was assigned to the band head of the ν1/2+[411] band. The transitions depopulating the high-K isomers to low-lying states also establish the relative energies of three low-lying one-quasiparticle bands, leading to a new spin-parity assignment of 7/2- to the ground state of Nd129. The partial half-lives of the depopulating transitions suggest spin-parities 21/2+, 19/2+, and 17/2+ for the three high-K isomers. The properties of the band built on the 21/2+ isomeric state suggest a one neutron-two proton configuration. Based on the results of extensive calculations with different models, we also assign one neutron-two proton configurations to the 19/2+ and 17/2+ isomeric states. The assigned configurations of the 17/2+ and 21/2+ isomeric states involve the π9/2+[404] orbital, which is identified in three-quasiparticle bands of proton-rich A≈130 nuclei.