Abstract

Excited states in the neutron-rich nucleus $^{150}$Ba have been observed via ${\rm \beta}$–${\rm \gamma}$ spectroscopy at the Radioactive Isotope Beam Factory, RIKEN Nishina Center. The $^{150}$Ba ions were produced by the in-flight fission of a $^{238}$U beam with an energy of 345 MeV/nucleon. The $E(2^{+})$ energy of $^{150}$Ba was identified at 100 keV, which is the lowest known in the neutron-rich Ba isotopes. A ${\rm \gamma}$-ray peak was also observed at 597 keV. A mean-field calculation with a fully 3D real space was performed and a static octupole deformation was obtained for the Ba isotopes. $K^{\pi}=0^{-}$ and $1^{-}$ excited states with significant octupole collectivity were newly predicted at around or lower than 1 MeV on the ground state of $^{150}$Ba by a random-phase approximation calculation. The 597 keV ${\rm \gamma}$ ray can be interpreted as a negative-parity state, showing that $^{150}$Ba may possess octupole collectivity.

Details

Title
Beta-gamma spectroscopy of the neutron-rich 150Ba
Author
Yokoyama, R 1 ; Ideguchi, E 2 ; Simpson, G S 3 ; Tanaka, Mn 2 ; Nishimura, S 4 ; Doornenbal, P 4 ; Lorusso, G 4 ; P-A Söderström 4 ; Sumikama, T 5 ; J Wu 6 ; Xu, Z Y 7 ; Aoi, N 2 ; Baba, H 4 ; Bello Garrote, F L 8 ; Benzoni, G 9 ; Browne, F 10 ; Daido, R 11 ; Fang, Y 11 ; Fukuda, N 4 ; Gottardo, A 12 ; Gey, G 13 ; S Go 1 ; Inabe, N 4 ; Isobe, T 4 ; Kameda, D 4 ; Kobayashi, K 14 ; Kobayashi, M 1 ; Kojouharov, I 15 ; Komatsubara, T 16 ; Kubo, T 4 ; Kurz, N 15 ; Kuti, I 17 ; Z Li 6 ; Matsushita, M 1 ; Michimasa, S 1 ; Moon, C B 18 ; Nishibata, H 11 ; Nishizuka, I 5 ; Odahara, A 11 ; Patel, Z 19 ; Rice, S 19 ; Sahin, E 8 ; Sakurai, H 20 ; Schaffner, H 15 ; Sinclair, L 21 ; Suzuki, H 4 ; Takeda, H 4 ; Taprogge, J 22 ; Vajta, Zs 17 ; Watanabe, H 23 ; Yagi, A 11 ; Inakura, T 24 

1  Center for Nuclear Study, the University of Tokyo, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan 
2  Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan 
3  LPSC, 53 Rue des Martyrs, F-38026 Grenoble Cedex, France 
4  RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan 
5  Department of Physics, Tohoku University, Aramaki-aza-aoba, Aoba, Sendai, Miyagi 980-8578, Japan 
6  School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China 
7  Department of Physics, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan 
8  Department of Physics, University of Oslo, P. O. Box 1072 Blindern, 0316 Oslo, Norway 
9  INFN, Sezione di Milano, I-20133 Milano, Italy 
10  RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan; School of Computing, Engineering and Mathematics, University of Brighton, Brighton BN2 4GJ, UK 
11  Department of Physics, Osaka University, Machikaneyama-chou 1-1, Osaka 560-0043 Toyonaka, Japan 
12  Dipartimento di Fisica dell’Università degli Studi di Padova, I-35131 Padova, Italy; INFN, Laboratori Nazionali di Legnaro, Legnaro I-35020, Italy 
13  LPSC, 53 Rue des Martyrs, F-38026 Grenoble Cedex, France; Institut Laue-Langevin, B.P. 156, F-38042 Grenoble Cedex 9, France 
14  Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan 
15  GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany 
16  Research Facility Center for Pure and Applied Science, University of Tsukuba, Ibaraki 305-8577, Japan; Rare Isotope Science Project, Institute for Basic Science, Daejeon 305-811, Korea 
17  MTA Atomki, P.O. Box 51, Debrecen, H-4001, Hungary 
18  Hoseo University, Asan, Chungnam 336-795, Korea 
19  RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan; Department of Physics, University of Surrey, Guildford GU2 7XH, UK 
20  RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan; Department of Physics, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan 
21  RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan; Department of Physics, University of York, Heslington, York YO10 5DD, UK 
22  Instituto de Estructura de la Materia, CSIC, E-28006 Madrid, Spain; Departamento de Física Teórica, Universidad Autónoma de Madrid 
23  RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan; International Research Center for Nuclei and Particles in the Cosmos, Beihang University, Beijing 100191, China; School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191, China 
24  Department of Physics, Niigata University, Niigata 950-2181, Japan 
Publication year
2018
Publication date
Apr 2018
Publisher
Oxford University Press
e-ISSN
20503911
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1093/ptep/pty037
ProQuest document ID
3171480824
Copyright
© The Author(s) 2018. Published by Oxford University Press on behalf of the Physical Society of Japan. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.