Theoretical investigation of the antimagnetic rotation in $^{104}$Pd

Abstract

The particle-number-conserving method based on the cranked shell model is used to investigate the antimagnetic rotation band in $^{104}$Pd. The experimental moments of inertia and reduced $B(E2)$ transition probabilities are reproduced well. The $J^{(2)}/B(E2)$ ratios are also discussed. The occupation probability of each orbital close to the Fermi surface and the contribution of each major shell to the total angular momentum alignment with rotational frequency are analyzed. The backbending mechanism of the ground state band in $^{104}$Pd is understood clearly and the configuration of the antimagnetic rotation after backbending is clarified. In addition, the crossing of a four quasiparticle states with this antimagnetic rotation band is also predicted. By examining the the closing of the four proton hole angular momenta towards the neutron angular momenta, the "two-shears-like" mechanism for this antimagnetic rotation is investigated and two stages of antimagnetic rotation in $^{104}$Pd are seen clearly.