Nucleon correlations and the structure of [formula omitted

S Bottoni,D Seweryniak,B Bucher,A Korichi,P Fallon,Y Tsunoda,T Lauritsen,J Sethi,A Wiens,A Gade,M Cromaz,D Cline,J Harker,R V F Janssens ,D Weißhaar ,C M Campbell ,H L Crawford ,A B Hayes ,C J Chiara ,C R Hoffman ,H M David ,B P Kay ,A D Ayangeakaa ,S J Zhu ,C Y Wu ,Takaharu Otsuka ,W B Walters ,J P Greene ,A O Macchiavelli ,M P Carpenter ,M Q Buckner

doi:10.1016/j.physletb.2017.11.003

Abstract

The structure of 71Zn was investigated by one-neutron transfer and heavy-ion induced complex (deep-inelastic) reactions using the GRETINA-CHICO2 and the Gammasphere setups, respectively. The observed inversion between the 9/2+ and 1/2− states is explained in terms of the role of neutron pairing correlations. Non-collective sequences of levels were delineated above the 9/2+ isomeric state. These are interpreted as being associated with a modest oblate deformation in the framework of Monte-Carlo shell-model calculations carried out with the A3DA-m Hamiltonian in the pfg9/2d5/2 valence space. Similarities with the structure of Ni402868 were observed and the shape-coexistence mechanism in the N=40 region of neutron-rich nuclei is discussed in terms of the so-called Type-II shell evolution, with an emphasis on proton–neutron correlations between valence nucleons, especially those involving the shape-driving g9/2 neutron orbital.

Highlights

The structure of 71Zn was investigated by one-neutron transfer and heavy-ion induced complex reactions using the GRETINA-CHICO2 and the Gammasphere setups, respectively
Non-collective sequences of levels were delineated above the 9/2+ isomeric state. These are interpreted as being associated with a modest oblate deformation in the framework of Monte-Carlo shellmodel calculations carried out with the A3DA-m Hamiltonian in the p f g9/2d5/2 valence space
= 40 region of neutron-rich nuclei is discussed in terms of the so-called Type-II shell evolution, with an emphasis on proton–neutron correlations between valence nucleons, especially those involving the shape-driving g9/2 neutron orbital

Summary

Introduction

The structure of 71Zn was investigated by one-neutron transfer and heavy-ion induced complex (deepinelastic) reactions using the GRETINA-CHICO2 and the Gammasphere setups, respectively. The level scheme was extended to higher excitation energies as a result of the reaction mechanism employed which favors population of high-spin, yrast states.

Results

Conclusion