Progress report on research project 'Work performed on microscopic level densities using the HFB + combinatorial method'

Full text: A new Skyrme force has been developed in order to fit experimental masses with a pairing strength constrained on the odd-even mass differences. Using the HFB method with this force, single particle level schemes for both protons and neutrons have been generated for nearly 8000 nuclei. The combinatorial method has been applied to compute for each nucleus both the particle-hole and total state densities as a function of the energy, spin projections and parities. Rotational bands are explicitly treated to go from state densities to level densities, and the transition from deformed to spherical shape is also accounted for. Vibrational modes are treated using a phenomenological expression determined to fit the available experimental data for quadrupole and octupole phonons' energies. This new phenomenological expression includes shell effect to deal with the structures observed when looking at these experimental energies. The currently obtained results give an average accuracy comparable to what can be obtained with a global Back Shifted Fermi Gas model or to that already available with the HFB + statistical level densities of RIPL II. The impact of these new tabulated HFB + combinatorial level densities has also been studied with the TALYS code and tested on different cases. (author)