Persistence of Shape Coexistence in 68Zn

Determine whether the coexisting nuclear shapes observed in nickel isotopes persist in 68Zn when two protons beyond the Z = 28 shell closure are added.

Background

The paper investigates the low-spin structure of 68Zn as the first step toward a broader study of the zinc isotopic chain. Shape coexistence involving spherical, oblate, and prolate configurations has been established or predicted in several nickel isotopes, and preliminary Monte Carlo shell-model calculations for 68Zn predict four low-lying 0+ states associated with different deformations.

The authors explicitly identify the persistence of these coexisting shapes after adding two protons relative to the nickel isotopes as unresolved. The present measurements provide structural information and identify candidate deformed configurations, but do not establish whether the full shape-coexistence phenomenon persists in 68Zn.

References

It is unclear whether the aforementioned coexisting shapes of the Ni isotopes persist with these additional protons.

— Core Breaking at Low Spin in $^{68}$Zn from Nuclear Resonance Fluorescence  (2608.23514 - Johnson et al., 24 Aug 2026) in Introduction

Given the importance of the shape-driving 0g_{9/2} shell, this 0+_3 state remains a candidate for association with deformation. Unfortunately, no excited states built on this level could be identified in the coincidence data to place this conjecture on stronger footing.

— Core Breaking at Low Spin in $^{68}$Zn from Nuclear Resonance Fluorescence  (2608.23514 - Johnson et al., 24 Aug 2026) in Section Discussion, subsection “Shell-Model Interpretation of Levels Near the 68Zn Ground State”