First Observation of Multiple Transverse Wobbling Bands of Different Kinds in $^{183}$Au

TL;DR

This paper reports the first observation of two distinct transverse wobbling bands in $^{183}$Au, providing comprehensive experimental evidence and theoretical modeling of the complete transverse wobbling phenomenon in a single nucleus.

Contribution

It presents the first experimental observation of two different transverse wobbling bands in $^{183}$Au, with detailed analysis and theoretical support, demonstrating both increasing and decreasing wobbling energies with spin.

Findings

Observation of two transverse wobbling bands with different energy behaviors.

Experimental confirmation of the wobbling nature through $E2$ dominance and DCO measurements.

Particle rotor model calculations successfully reproduce the experimental data.

Abstract

We report the first observation of two wobbling bands in $^{183}$Au, both of which were interpreted as the transverse wobbling (TW) band but with different behavior of their wobbling energies as a function of spin. It increases (decreases) with spin for the positive (negative) parity configuration. The crucial evidence for the wobbling nature of the bands, dominance of the $E2$ component in the $\Delta I = 1$ transitions between the partner bands, is provided by the simultaneous measurements of directional correlation from the oriented states (DCO) ratio and the linear polarization of the $\gamma$ rays. Particle rotor model calculations with triaxial deformation reproduce the experimental data well. A value of spin, $I_m$, has been determined for the observed TW bands below which the wobbling energy increases and above which it decreases with spin. The nucleus $^{183}$Au is, so far, the only nucleus in which both the increasing and the decreasing parts are observed and thus gives the experimental evidence of the complete transverse wobbling phenomenon.