Deformation of 110Zr relative to mean‑field model predictions

Establish whether the zirconium isotope 110Zr exhibits a quadrupole deformation larger than that predicted by the mean‑field models used in Paul et al., Phys. Rev. Lett. 118, 032501 (2017), as suggested by existing spectroscopic measurements, thereby clarifying the ground‑state shape and benchmarking the accuracy of those mean‑field approaches in this region.

Background

The paper investigates nuclear masses and structure in the neutron‑rich zirconium region around the neutron midshell N≈66 using precision Penning‑trap measurements and comparisons to the BSkG2 energy‑density functional. Experimental trends near N≈60 and N≈66 challenge several mean‑field model predictions, highlighting competing triaxial minima and issues with collective corrections.

In discussing the evolution of deformation beyond N=67, the authors note that BSkG2 does not predict a pronounced T2 minimum despite low E(2+1) energies observed for 108Zr and 110Zr. They cite earlier spectroscopy of 110Zr and explicitly refer to a conjecture from Paul et al. (2017) that the spectroscopic information indicates a deformation larger than predicted by the mean‑field models used in that paper, framing an unresolved question about the true deformation of 110Zr and model performance.