# Physics of even-even superheavy nuclei with 96 < Z < 110 in the Quark-Meson-Coupling Model

## TL;DR

This study applies the Quark-Meson-Coupling model to super-heavy nuclei, analyzing shell gaps, shapes, and energies, and compares predictions with experimental data to understand nuclear structure in this extreme region.

## Contribution

It demonstrates the predictive capability of the QMC model for super-heavy nuclei, including shape transitions and shell gap predictions, based on mean-field calculations.

## Key findings

- Deviations from measured binding energies are less than 2.5 MeV.
- Shape transitions occur around N=168 and towards N=184.
- Unambiguous evidence for N=152 and 162 shell gaps from single-particle spectra.

## Abstract

The Quark-Meson-Coupling (QMC) model has been applied to the study of the properties of even-even super-heavy nuclei with 96 < Z < 110, over a wide range of neutron numbers. The aim is to identify the deformed shell gaps at N = 152 and N = 162 predicted in macroscopic-microscopic (macro-micro) models, in a model based on the mean-field Hartree-Fock+BCS approximation. The predictive power of the model has been tested on proton and neutron spherical shell gaps in light doubly closed (sub)shell nuclei. In the super-heavy region, the ground state binding energies of 98 < Z < 110 and 146 < N < 160 differ, in the majority of cases, from the measured values by less than 2.5 MeV, with the deviation decreasing with increasing Z and N. The axial quadrupole deformation parameter, calculated over the range of neutron numbers 138 < N < 184, revealed a prolate-oblate coexistence and shape transition around N = 168, followed by an oblate-spherical transition towards the expected N = 184 shell closure in Cm, Cf, Fm and No. The closure is not predicted in Rf, Sg, Hs and Ds as another shape transition to a highly deformed shape in Sg, Hs and Ds for N > 178 appears, while 288Rf (N = 184) remains oblate. The bulk properties predicted by QMC are found to have a limited sensitivity to the deformed shell gaps at N = 152 and 162. However, the evolution of the neutron single-particle spectra with 0 < beta2 < 0.55 gives unambiguous evidence for the location and size of the N = 152 and 162 gaps as a function of Z and N. In addition, the neutron number dependence of neutron pairing energies provides supporting evidence for existence of the energy gaps.