Multi-phonon $\gamma$-vibrational bands in odd-mass nuclei studied by triaxial projected shell model approach

TL;DR

This paper extends the triaxial projected shell model to analyze gamma-vibrational bands in odd-mass nuclei, successfully describing multi-phonon structures and supporting experimental observations of complex vibrational phenomena.

Contribution

The study introduces a new application of the triaxial projected shell model to odd-mass nuclei, enabling detailed analysis of gamma-vibrational structures and multi-phonon bands.

Findings

Model accurately describes ground-state and multi-phonon gamma-vibrations.

Supports experimental evidence of simultaneous one- and two-phonon gamma-bands.

Generalizes gamma-oscillation concepts to odd-mass nuclei.

Abstract

Inspired by the recent experimental data (Phys. Lett. B {\bf 675} (2009) 420), we extend the triaxial projected shell model approach to study the $\gamma$-band structure in odd-mass nuclei. As a first application of the new development, the $\gamma$-vibrational structure of $^{103}$Nb is investigated. It is demonstrated that the model describes the ground-state band and multi-phonon $\gamma$-vibrations quite satisfactorily, supporting the interpretation of the data as one of the few experimentally-known examples of simultaneous occurrence of one- and two-$\gamma$-phonon vibrational bands. This generalizes the well-known concept of the surface $\gamma$-oscillation in deformed nuclei built on the ground-state in even-even systems to $\gamma$-bands based on quasiparticle configurations in odd-mass systems.