α clustering from the formation of a pocket structure in the α-nucleus potential

We investigate the formation of a pocket structure in the alpha-nucleus potential based on the dynamic doublefolding potential model. We improve the model with the density-dependent Migdal nucleon-nucleon (NN) interaction and combine it with the nuclear medium effect. The improved potential naturally generates a pocket structure at the nuclear surface, which physically agrees with the characteristics suggested by the microscopic many-body calculations. The result reveals that the formation of the pocket structure is due to the strong Pauli repulsion caused by the variation of the NN interaction when the alpha cluster and the daughter nucleus have large density overlaps. The existence of the nuclear medium effect is essential to the physical self-consistency of the pocket position. These findings highlight the importance of the medium effect on the NN interaction and provide solid theoretical support for the understanding that alpha clustering occurs at the surface of heavy nuclei.