Tensor force and delta excitation for the structure of light nuclei

3rd International Workshop on "State of the Art in Nuclear Cluster Physics"

Horii, K.^1 ; Myo, T.^2,3 ; Toki, H.^3

Department of Physics, Tokyo Institute of Technology, Meguro

152-8551, Japan^1

Faculty of Engineering, Osaka Institute of Technology, Osaka

535-8585, Japan^2

Research Center for Nuclear Physics (RCNP), Osaka University, Osaka

567-0047, Japan^3

关键词: Body channels;    Body potential;    Few body systems;    Matrix elements;    Nucleon-nucleon interaction;    Tensor force;    Three-body force;    Three-body systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/569/1/012076/pdf
DOI  :  10.1088/1742-6596/569/1/012076

来源: IOP

【 摘 要 】

We treat explicitly Δ(1232) isobar degrees of freedom using a bare nucleon-nucleon interaction for few-body systems, where Δ excitations can be the origin of the three-body force via the pion exchange. We adopt the Argonne two-body potential including Δ, named as AV28 potential, and study the role of Δ explicitly in two-body and three-body systems. It was found that the additional Δ states generate strong tensor correlations caused by the transitions between N and Δ states, and change tensor matrix elements largely from the results with only nucleons. We studied the effects of three-body force in the triton and obtained 0.8 MeV attraction due to the intermediate Δ excitation. Due to the lack of the total binding energy for the triton in the delta model, we further studied carefully the effects of the delta excitation in various two body channels and compared with the nucleon only model in the AV14 potential. We modified slightly the AV28 potential in the singlet S channel so that we could reproduce the triton binding energy due to the appropriate amount of the three-body force effects.