Microscopic structure of coexisting 0+ states in 68Ni probed via two-neutron transfer

Phys. Rev. C

99
054332
(2019)
F. Flavigny, J. Elseviers, A. N. Andreyev, C. Bauer, V. Bildstein, A. Blazhev, B. A. Brown, H. De Witte, J. Diriken, V. N. Fedosseev, S. Franchoo, R. Gernhäuser, M. Huyse, S. Ilieva, S. Klupp, Th. Kröll, R. Lutter, B. A. Marsh, D. Mücher, K. Nowak, T. Otsuka, J. Pakarinen, N. Patronis, R. Raabe, F. Recchia, P. Reiter, T. Roger, S. Sambi, M. Seidlitz, M. D. Seliverstov, B. Siebeck, Y. Tsunoda, P. Van Duppen, M. Vermeulen, M. Von Schmid, D. Voulot, N. Warr, F. Wenander and K. Wimmer

The structure of low-spin states originating from shape-coexisting configurations in  
68
40
 Ni 
28
  was directly probed via the two-neutron transfer reaction  
66
 Ni 
 ⁢(𝑡,𝑝)⁢ 
68
 Ni 
  in inverse kinematics using a radioactive ion beam on a radioactive target. The direct feeding to the first excited 0+ state was measured for center-of-mass angles 4∘–16∘ and amounts to an integral of 4.2(16)% relative to the ground state. The observed difference in feeding of the 0+ states is explained by the transfer of neutrons, mainly in the 𝑝⁢𝑓 shell below 𝑁=40 for the ground state, and across 𝑁=40 in the 𝑔9/2 orbital for the 0+
2, based on second-order distorted-wave Born approximation calculations combined with state-of-the-art shell-model two-nucleon amplitudes. However, the direct feeding to the 2+
1 state [29(3)%] is incompatible with these calculations.

DOI
https://doi.org/10.1103/PhysRevC.99.054332
Published on
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