Particle-number conserving analysis for the systematics of high-Kpair-broken bands in Hf and Lu isotopes(170⩽A⩽178)

Abstract

Within the framework of the particle-number conserving (PNC) formalism, one-quasiparticle and low-lying high-K pair-broken (multiquasiparticle) bands systematically observed in Hf and Lu isotopes (170{<=}A{<=}178) are analyzed consistently. The PNC method deals with the cranked shell model with pairing interaction, in which the Pauli blocking effects are exactly accounted for, and the pairing interaction strength is determined by the experimental odd-even difference in binding energies. With an appropriate Nilsson level scheme that best fits the experimental bandhead energies of the one-quasiparticle bands, the experimental moments of inertia (MOIs) of these one-quasiparticle and multiquasiparticle bands (including configuration and frequency dependences, signature splitting, etc.) can be well reproduced without any additional free parameter. In most cases, the PNC formalism supports the configuration assignments in earlier works. the PNC calculation also reveals that the experimental systematics of low-lying high-K pair-broken bands in Hf and Lu isotopes are intimately related to the subshell effects near the Fermi surfaces of both protons and neutrons.