Towards a consistent understanding of the exotic nucleus 4214Si28

Abstract

The issue of magicity of  has been a contentious one. Fridmann et al., through studies of two-proton knockout reaction , presented strong evidence in support of magicity and sphericity of . However in complete conflict with this, Bastin et al., gave equally strong empirical evidence, to show that the N = 28 magicity had completely collapsed in  to make it well deformed. The consensus at present though is in favour of the validity of the latter experiment. However, our QCD based theoretical model supports the result of Fridmann experiment. They had explored the amazing persistence of the unique exotic nucleus as a stable structure within the nucleus; even after stripping off six-protons through the isotonic chain:. Thus it is the novel and unexpected stability of proton shell closure at Z=14 in, which is playing such a dominant role in ensuring its magicity, while the neutron magic number N = 28, goes into hiding or actually disappears. Recently, SAA has shown that the fusion experiment of a beam of halo nucleus ⁶He with the target nucleus ²³⁸U , actually provided strong evidence that the “core” of the halo nucleus has the structure of a tennis-ball (bubble) like nucleus, with a “hole” at the centre of its density distribution. This provides us with clear-cut support for our Quantum Chromodynamics based model of clusters of tritons in neutron-rich nuclei. Here we show that our QCD based model, provides support to Fridmann et al. , showing that,  has a spherically magic structure of 14  (14-tritons) with a tennis-ball (bubble) like structure with “hidden” N=28 neutrons.