Tests of collectivity in $^{98}$Zr by absolute transition rates

TL;DR

This study measured lifetimes of low-spin states in $^{98}$Zr using advanced techniques, providing data that tests nuclear models and reveals complex nuclear structure features.

Contribution

First lifetime measurements of six low-spin states in $^{98}$Zr, including four previously unknown, and comparison with theoretical models to explore nuclear structure.

Findings

Most $B(E2)$ values are well reproduced by models

Some low-lying states' structures remain challenging to explain

Data enhances understanding of shape coexistence in $^{98}$Zr

Abstract

Lifetimes of low-spin excited states in $^{98}$Zr were measured using the recoil-distance Doppler-shift technique and the Doppler-shift attenuation method. The nucleus of interest was populated in a $^{96}$Zr($^{18}$O,$^{16}$O)$^{98}$Zr two-neutron transfer reaction at the Cologne FN Tandem accelerator. Lifetimes of six low-spin excited states, of which four are unknown, were measured. The deduced $B(E2)$ values were compared with Monte Carlo shell model and interacting boson model with configuration mixing calculations. Both approaches reproduce well most of the data but leave challenging questions regarding the structure of some low lying states.