2016/01/22 by H. Matsuno, Matsuno, H., N. Itagaki +1
Physics and Astronomy · #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #nucl-ex #nucl-th
paper · pdf · doi:10.48550/arxiv.1601.05892
arxiv created 2016/01/22 · arxiv updated 2016/01/25
In 16O, we investigate the relation between the E0 monopole transition matrix elements and cluster-shell competition using antisymmetrized quasi cluster model (AQCM), where the dissolution of alpha clusters into quasi clusters due to the effect of the spin-orbit force is introduced. We focus on the structure change when the strength of the spin-orbit force is varied. The ground state dominantly has a compact four alpha structure (doubly magic structure of the p shell), which is rather independent of the strength. However the first excited state (02+) has 12C+alpha cluster structure and this state is largely affected by the increase of the strength; the subclosure configuration of the p3/2 shell for the 12C cluster part becomes more important than three alpha configuration. The E0 transition from the ground state with compact four alpha configuration to the 0+2 state with 12C+alpha cluster configuration is suppressed when increasing the spin-orbit strength. Although the E0 operator itself does not have the spin dependence, the matrix element is sensitive to the difference of intrinsic spin structures of the two states. The E0 transition characterizes the persistence of four alpha structure in the 0+2 state.