Multi-phonon ${\hat{I}}^3$-vibrational bands in odd-mass nuclei studied by triaxial projected shell model approach

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 ${\hat{I}}^3$-band structure in odd-mass nuclei. As a first application of the new development, the ${\hat{I}}^3$-vibrational structure of ${}^{103}$Nb is investigated. It is demonstrated that the model describes the ground-state band and multi-phonon ${\hat{I}}^3$-vibrations quite satisfactorily, supporting the interpretation of the data as one of the few experimentally-known examples of simultaneous occurrence of one- and two-${\hat{I}}^3$-phonon vibrational bands. This generalizes the well-known concept of the surface ${\hat{I}}^3$-oscillation in deformed nuclei built on the ground-state in even-even systems to ${\hat{I}}^3$-bands based on quasiparticle configurations in odd-mass systems.

10 pages, 3 figures