Tensor and pairing interactions within the quark-meson coupling energy-density functional

Abstract

In the latest version of the quark-meson coupling (QMC) model, QMCπ-III-T, the density functional is improved to include the tensor component quadratic in the spin current and a pairing interaction derived in the QMC framework. Traditional pairing strengths are expressed in terms of the QMC parameters and the parameters of the model optimized. A variety of nuclear observables are calculated with the final set of parameters. The inclusion of the tensor component improves the predictions for ground-state bulk properties, while it has a small effect on the single-particle spectra. Further, its effect on the deformation of selected nuclei is found to improve the energies of doubly magic nuclei at sphericity. Changes in the energy curves along the Zr chain with increasing deformation are investigated in detail. The new pairing functional is also applied to the study of neutron shell gaps, where it leads to improved predictions for subshell closures in the superheavy region.