Superheavy nuclei in a relativistic effective Lagrangian model

Abstract

Isotopic and isotonic chains of superheavy nuclei are analyzed to search for spherical double shell closures beyond $Z=82$ and $N=126$ within the new effective field theory model of Furnstahl, Serot, and Tang for the relativistic nuclear many-body problem. We take into account several indicators to identify the occurrence of possible shell closures, such as two-nucleon separation energies, two-nucleon shell gaps, average pairing gaps, and the shell correction energy. The effective Lagrangian model predicts $N=172$ and $Z=120$ and $N=258$ and $Z=120$ as spherical doubly magic superheavy nuclei, whereas $N=184$ and $Z=114$ show some magic character depending on the parameter set. The magicity of a particular neutron (proton) number in the analyzed mass region is found to depend on the number of protons (neutrons) present in the nucleus.