Low-lying structure and shape evolution in neutron-rich Se isotopes

S. Chen (1, 2) , P. Doornenbal (1) , A. Obertelli (3, 1) , T.R. Rodriguez (4) , G. Authelet (3) , H. Baba (1) , D. Calvet (3) , T. Motobayashi (1) , F. Château (3) , A. Corsi (3) , A. Delbart (3) , J.-M. Gheller (3) , A. Giganon (3) , A. Gillibert (3) , A. Gottardo (5) , V. Lapoux (3) , J.-Y. Roussé (3) , H. Sakurai (1) , D. Steppenbeck (1) , C. Santamaria (3) , Taniuchi R. (1, 6) , Uesaka T. (1) , I. Stefan (5) , M. Niikura (6) , N. Paul (3) , Ando T. (1, 6) , Arici T. (7) , Blazhev. A. (8) , Bruce A. M. (9) , R. Caroll (10) , L.X. Chung (11) , M.L. Cortés (12, 7) , M. Dewald (8) , B. Ding (13) , F. Flavigny (5) , S. Franchoo (5) , M. Górska (7) , A. Jungclaus (14) , J. Lee (15) , M. Lettmann (12) , B.D. Linh (11) , J. Liu (15) , Z. Liu (13) , C. Lizarazo (7, 12) , S. Momiyama (1, 6) , K. Moschner (8) , S. Nagamine (1, 6) , N. Nakatsuka (16, 1) , C.R. Nita (17) , C. Nobs (9) , L. Olivier (5) , R. Orlandi (18) , Z. Patel (10) , Zs. Podolyak (10) , M. Rudigier (10) , T. Saito (1, 6) , C. Shand (10) , P.-A. Söderström (1) , V. Vaquero (14) , V. Werner (12) , K. Wimmer (6) , Z. Xu (15)

1 RIKKEN-Saimata
2 School of Physics and State Key Laboratory of Nuclear Physics and Technology
3 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
4 Departamento de FisicaTeorica e IFT-UAM/CSIC
5 IPNO - Institut de Physique Nucléaire d'Orsay
6 Department of Physics, University of Tokyo, Bunkyo, Tokyo
7 GSI - Gesellschaft für Schwerionenforschung
8 Institut für Kernphysik der Universität zu Köln
9 Brighton - School of Computing, Engineering and Mathematics
10 UNIS - University of Surrey
11 Institute for Nuclear Science and Technique, VINATOM
12 Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt
13 IMP - Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
14 Instituto de Estructura de la Materia
15 Department of Physics
16 DEPARTMENT OF PHYSICS, KYOTO UNIVERSITY - Department of Physics, Kyoto University
17 NIPNE - Horia Hulubei National Institute of Physics and Nuclear Engineering
18 Advanced Science Research Center

Neutron-rich $^{88,90,92,94}$ Se isotopes were studied via in-beam $\gamma$-ray spectroscopy after nucleon removal reactions at intermediate energies at the Radioactive Isotope Beam Factory. Based on gamma-gamma coincidence analysis, low-lying excitation level schemes are proposed for these nuclei, including the 2$_1^+$, 4$_1^+$ states and 2$_2^+$ states at remarkably low energies. The low-lying 2$_2^+$ states, along with other features, indicate triaxiality in these nuclei. The experimental results are in good overall agreement with self-consistent beyond-mean-field calculations based on the Gogny D1S interaction, which suggests both triaxial degree of freedom and shape coexistence playing important roles in the description of intrinsic deformations in neutron-rich Se isotopes.

Mots clés: NUCLEI

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

S. Chen, P. Doornenbal, A. Obertelli, T.R. Rodriguez, G. Authelet, et al.. Low-lying structure and shape evolution in neutron-rich Se isotopes. Physical Review C, 2017, 95, pp.041302(R). ⟨10.1103/PhysRevC.95.041302⟩. ⟨cea-01538442⟩