The force used in the Hartree-Fock-Bogoliubov (HFB) mass model is an extended Skyrme force (containing t4 and t5 terms), along with a 4-parameter delta-function pairing force derived from realistic calculations of infinite nuclear and neutron matter.
Pairing correlations are introduced in the framework of the Bogoliubov method. Deformations with axial and left-right symmetry are admitted.
The total binding energy is given by
Etot = EHFB+ Ewigner
- EHFB is the HFB binding energy including a cranking correction to the spurious rotational energy and a phenomenological vibration correction energy
- Ewigner=Vw exp(-λ((N-Z)/A)2)+Vw|N-Z|exp(-(A/A0)2) is a phenomenological correction for the Wigner energy.
The parameter set, labelled BSk24, is determined by constraining the nuclear-matter symmetry coefficient to J = 30 MeV and the isoscalar effective mass to M*s/M = 0.8 and optimizing the fit to the full data set of the 2353 measured masses with N,Z ≥ 8 (both spherical and deformed) of Audi et al. [Chinese Physics C36, 1287 (2012)]: the corresponding root mean square error is 0.549 MeV for this data set.