Long-lived K isomer and enhanced γ vibration in the neutron-rich nucleus 172Dy: Collectivity beyond double midshell

Physics Letters B

C.-B. Moon¹  G.J. Lane²  C.S. Lee³  P.S. Lee³  T. Alharbi⁴  A. Yagi⁵  A. Odahara⁵  S. Kanaya⁵  H. Kanaoka⁵  E.J. Lee⁶  K.Y. Chae⁶  I. Nishizuka⁷  T. Sumikama⁷  R.J. Carroll⁸  P.H. Regan⁸  P.M. Walker⁸  C.M. Shand⁸  Z. Patel⁸  Zs. Podolyák⁸  S. Lalkovski⁸  G. Lotay⁸  Z.Y. Xu⁹  J.J. Liu⁹  I. Kojouharov^1,10  H. Schaffner^1,10  N. Kurz^1,10  K. Yoshida^1,11  J.J. Valiente-Dóbon^1,12  I. Kuti^1,13  Z. Korkulu^1,13  Zs. Dombradi^1,13  Zs. Vajta^1,13  F.G. Kondev^1,14  T. Kubo^1,15  V.H. Phong^1,15  H. Takeda^1,15  P.-A. Söderström^1,15  J. Wu^1,15  S. Nishimura^1,15  H. Suzuki^1,15  D.S. Ahn^1,15  P. Doornenbal^1,15  Y. Shimizu^1,15  N. Inabe^1,15  H. Baba^1,15  T. Isobe^1,15  N. Fukuda^1,15  H. Sakurai^1,15  S. Kubono^1,15  G. Lorusso^1,15  E. Ideguchi^1,16  C.R. Nita^1,17  A.M. Bruce^1,17  F. Browne^1,17  A. Estrade^1,18  C. Griffin^1,18  G.X. Zhang^1,19  H. Watanabe^1,19  S. Terashima^1,19  O.J. Roberts^2,20 

[1] Department of Display Engineering, Hoseo University, Chung-Nam 336-795, Republic of Korea;Department of Nuclear Physics, R.S.P.E., Australian National University, Canberra, A.C.T 0200, Australia;Department of Physics, Chung-Ang University, Seoul 156-756, Republic of Korea;Department of Physics, College of Science in Zulfi, Almajmaah University, P.O. Box 1712, 11932, Saudi Arabia;Department of Physics, Osaka University, Machikaneyama-machi 1-1, Osaka 560-0043 Toyonaka, Japan;Department of Physics, Sungkyunkwan University, Suwon 440-746, Republic of Korea;Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan;Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom;Department of Physics, the University of Hong Kong, Pokfulam Road, Hong Kong;GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany;Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan;Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, 35020 Legnaro, Italy;MTA Atomki, P.O. Box 51, Debrecen, H-4001, Hungary;Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439, USA;RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan;Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki, Osaka 567-0047, Japan;School of Computing Engineering and Mathematics, University of Brighton, Brighton, BN2 4GJ, United Kingdom;School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom;School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China;School of Physics, University College Dublin, Belfield, Dublin 4, Ireland;

关键词: 172Dy;    K isomer;    Decay spectroscopy;    Axial symmetry;    γ vibration;   

DOI  :  10.1016/j.physletb.2016.07.057

来源: DOAJ

【 摘 要 】

The level structure of 172Dy has been investigated for the first time by means of decay spectroscopy following in-flight fission of a 238U beam. A long-lived isomeric state with T1/2=0.71(5) s and Kπ=8− has been identified at 1278 keV, which decays to the ground-state and γ-vibrational bands through hindered electromagnetic transitions, as well as to the daughter nucleus 172Ho via allowed β decays. The robust nature of the Kπ=8− isomer and the ground-state rotational band reveals an axially-symmetric structure for this nucleus. Meanwhile, the γ-vibrational levels have been identified at unusually low excitation energy compared to the neighboring well-deformed nuclei, indicating the significance of the microscopic effect on the non-axial collectivity in this doubly mid-shell region. The underlying mechanism of enhanced γ vibration is discussed in comparison with the deformed Quasiparticle Random-Phase Approximation based on a Skyrme energy-density functional.

【 授权许可】

Unknown