Transverse wobbling motion in $^{134}$Ce and $^{136}$Nd

TL;DR

This paper reports the first observation of transverse wobbling bands, including one- and two-phonon modes, in even-even nuclei $^{134}$Ce and $^{136}$Nd, supported by experimental data and theoretical calculations.

Contribution

It introduces the first evidence of transverse wobbling motion, including two-phonon bands, in even-even nuclei, supported by experimental and theoretical analysis.

Findings

Identification of one-phonon and two-phonon wobbling bands in $^{134}$Ce and $^{136}$Nd

Wobbling frequencies decrease with increasing spin, indicating transverse wobbling

Good agreement between experimental wobbling frequencies and harmonic frozen approximation calculations

Abstract

The existence of one-phonon and possible two-phonon transverse wobbling bands is proposed for the first time in two even-even nuclei, $^{134}$Ce and $^{136}$Nd. The predominant $E2$ character of the $\Delta I = 1$ transitions connecting the one-phonon wobbling band in $^{134}$Ce to the two-quasiparticle yrast band supports the wobbling interpretation. The extracted wobbling frequencies decrease with increasing spin, indicating the transverse character of the wobbling motion, with the angular momenta of the two quasiparticles aligned perpendicular to the axis of collective rotation. A candidate for two-phonon wobbling motion is also proposed in $^{136}$Nd. The wobbling frequencies calculated in the harmonic frozen approximation are in good agreement with the experimental ones for both the$^{134}$Ce and $^{136}$Nd nuclei.