Quadrupole Phonons in the Cadmium Isotopes

TL;DR

This paper investigates the vibrational properties of Cadmium isotopes using a boson Hamiltonian with partial U(5) symmetry, revealing that vibrational character persists in most low-lying states despite symmetry breaking.

Contribution

It introduces a boson Hamiltonian with partial U(5) dynamical symmetry to explain quadrupole phonons in Cadmium isotopes, highlighting the preservation of vibrational features.

Findings

U(5) symmetry preserved in spectrum segments

Small mixing with intruder states

Vibrational character maintained in low-lying states

Abstract

A key question concerning the spherical-vibrator attributes of states in Cadmium isotopes is addressed by means of a boson Hamiltonian encompassing U(5) partial dynamical symmetry. The U(5) symmetry is preserved in a segment of the spectrum and is broken in particular non-yrast states, and the resulting mixing with the intruder states is small. The vibrational character is thus maintained in the majority of low-lying normal states, as observed in $^{110}$Cd.