Study of the Electric Quadruple Moment of One-proton Halo Nucleus 8B by Using the Two-body Model, the Collective Model and the Microscopic Single-particle Shell Model

The nuclear electric quadruple moment of the proton-rich weakly bound Boron-8 (⁸B) halo nucleus is investigated using three theoretical approaches: the microscopic single-particle shell model, the collective model, and the two-body model. These approaches provide a reasonable prediction of the quadruple deformation that occurred due to the core polarization and many-body effects. These approaches also provide how the extended proton distribution influences the quadruple moment. The experimental value of electric quadruple moment (Q) of 8B is 6.45 efm². While the calculated value using the two-body model is 6.86 efm² and the collective model gives 5.83 efm² and the microscopic single particle shell model gives 4.03 efm². The ⁸B nucleus is a one-proton halo structure with a loosely bound valence proton outside a ⁷Be core, and it is an excellent candidate for studying nuclear deformation and quadruple effects near the proton drip-line. By comparing the predictions of these models with available experimental data, it can be measured their effectiveness in describing ⁸B’s structure. These predictions reveal the structure of the halo configuration that influences the quadruple properties of exotic nuclei.