Physics Letters B (Aug 2024)
First observation of excited states in 120La and its impact on the shape evolution in the A ≈ 120 mass region
- P.M. Jodidar,
- C.M. Petrache,
- B.F. Lv,
- E.A. Lawrie,
- A. Astier,
- S. Guo,
- K.K. Zheng,
- K. Auranen,
- A.D. Briscoe,
- T. Grahn,
- P.T. Greenlees,
- A. Illana,
- H. Joukainen,
- R. Julin,
- J. Louko,
- M. Luoma,
- H. Jutila,
- J. Ojala,
- J. Pakarinen,
- A.M. Plaza,
- P. Rahkila,
- P. Ruotsalainen,
- J. Sarén,
- A. Tolosa-Delgado,
- J. Uusitalo,
- G. Zimba,
- I. Kuti,
- A. Krakó,
- C. Andreoiu,
- D.T. Joss,
- R.D. Page,
- E.A. Cederlöf,
- A. Ertoprak
Affiliations
- P.M. Jodidar
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France; Corresponding authors.
- C.M. Petrache
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France; Corresponding authors.
- B.F. Lv
- Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; School of Nuclear Science and Technology, University of Chinese Academy of Science, Beijing 100049, China; Corresponding authors.
- E.A. Lawrie
- iThemba LABS, Natural Research Foundation, PO Box 722, 7129 Somerset West, South Africa
- A. Astier
- Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405 Orsay, France
- S. Guo
- Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; School of Nuclear Science and Technology, University of Chinese Academy of Science, Beijing 100049, China
- K.K. Zheng
- Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; School of Nuclear Science and Technology, University of Chinese Academy of Science, Beijing 100049, China
- K. Auranen
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- A.D. Briscoe
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland; Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
- T. Grahn
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- P.T. Greenlees
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- A. Illana
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- H. Joukainen
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- R. Julin
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- J. Louko
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- M. Luoma
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- H. Jutila
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- J. Ojala
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- J. Pakarinen
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- A.M. Plaza
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland; Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
- P. Rahkila
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- P. Ruotsalainen
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- J. Sarén
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- A. Tolosa-Delgado
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- J. Uusitalo
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- G. Zimba
- Accelerator Laboratory, Department of Physics, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- I. Kuti
- Institute for Nuclear Research (Atomki-ELKH), 4001 Debrecen, Hungary
- A. Krakó
- Institute for Nuclear Research (Atomki-ELKH), 4001 Debrecen, Hungary
- C. Andreoiu
- Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
- D.T. Joss
- Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
- R.D. Page
- Oliver Lodge Laboratory, Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
- E.A. Cederlöf
- KTH Department of Physics, S-10691 Stockholm, Sweden
- A. Ertoprak
- KTH Department of Physics, S-10691 Stockholm, Sweden
- Journal volume & issue
-
Vol. 855
p. 138806
Abstract
Excited states have been observed for the first time in the very neutron-deficient odd-odd nucleus 57120La63. The observed γ rays have been assigned based on coincidences with lanthanum X rays measured with the JUROGAM 3 array and with A=120 fusion-evaporation residues measured with the MARA separator. The observed γ rays form a rotational band which decays to the ground state via a cascade of four low-energy transitions. Based on the systematic comparisons with the heavier odd-odd La isotopes we assign spin-parity 4+ to the ground state and a πh11/2⊗νh11/2 configuration to the rotational band. The nuclear shape has been investigated by the cranked Nilsson-Strutinsky model. Two quasiparticle plus triaxial rotor model calculations including the np interaction nicely reproduce the spin of the inversion between the even- and odd-spin cascades of E2 transitions, giving credit to the np interaction as an important parameter responsible for the mechanism inducing the inversion. The position of the Fermi levels, in particular for neutrons, also has a strong impact on the observed inversion in the chain of lanthanum nuclei.
