Persistent vibrational structure in $^{110-116}$Cd

TL;DR

This paper demonstrates that low-lying states in $^{110-116}$Cd exhibit persistent vibrational structures, coexisting with gamma-soft intruder states, and introduces a Hamiltonian with partial dynamical symmetry to explain deviations.

Contribution

It presents a unified interpretation of vibrational and intruder states in $^{110-116}$Cd using a Hamiltonian with U(5) partial dynamical symmetry.

Findings

Normal states show vibrational characteristics consistent with empirical spectra.

Intruder states form a gamma-soft band coexisting with normal states.

Deviations are explained by a Hamiltonian with partial dynamical symmetry.

Abstract

The empirical spectra and $E2$ decay rates in $^{110,112,114,116}$Cd are shown to be consistent with a vibrational interpretation for low-lying normal states, coexisting with a single deformed $\gamma$-soft band of intruder states. The observed deviations from this paradigm show up in particular non-yrast states, which are properly described by a Hamiltonian with U(5) partial dynamical symmetry. The latter is characterized by a good (broken) symmetry in most (in selected) normal states, weakly coupled to intruder states.