Two 9Li clusters connected with two valence neutrons in 20C
Abstract
Many preceding works have shown in 11Li the presence of the halo structure comprised of the weakly bound two neutrons around 9Li, and it is intriguing to see how this halo structure changes when another 9Li approaches. In this study, we introduce a four-body model for 20C with two 9Li clusters and two valence neutrons. The recent development of the antisymmetrized quasi cluster model (AQCM) makes it possible to generate jj-coupling shell-model wave functions from α cluster models. Here, jj-coupling shell model wave function of 9Li is regarded as a cluster, which corresponds to the subclosure configuration of p3/2 for the neutrons, and we discuss how the two neutrons connect two 9Li clusters. Until now, most of the clusters in the conventional models have been limited to the closures of the three-dimensional harmonic oscillators, such as 4He, 16O, and 40Ca; however, owing to AQCM, it is feasible to utilize the jj-coupling shell model wave functions as plural subsystems quite easily. The appearance of a rotational band structure with a cluster structure around the four-body threshold energy is discussed.