First identification of a doublet wobbling excitation mode in ${}^{105}$Pd

Abstract

An experimental investigation of ${}^{105}$Pd has revealed, for the first time, the existence of two wobbling bands, both having one phonon configuration and originating from excitation which is the wobbling from the yrast band with the $h_{11/2}$ quasineutron fully aligned with the short axis, and from an excited band with the same quasineutron but with less alignment along the short axis. These observations have been drawn from the measured ratios of the inter-band and intra-band gamma transition rates. Model calculations based on the triaxial projected shell model (TPSM) approach have been performed and are found to be in good agreement with the experimental energies and relative transition probabilities. The analysis of the TPSM results provides an insight into the nature of the observed structures at a microscopic level.