Puzzling Radii of Calcium Isotopes: 40 Ca → 44 Ca → 48 Ca → 52 Ca, and Duality in the Structure of 4214 Si28 and 4820 Ca28
Abstract
In this paper we study the issue of the puzzle of the radii of calcium isotopes. Despite an excess of eight neutrons, strangely 48 Ca exhibits essentially the same charge radius as 40 Ca does. A fundamental microscopic description of this is still lacking. Also strange is a peak in charge radius of calcium at N = 24. The 52 Ca (N = 32) nucleus, well known to be doubly magical, amazingly has recently been found to have a very large charge radius. Also amazing is the property of 4214 Si28 which simultaneously appears to be both magical/spherical and strongly deformed as well. We use a Quantum Chromodynamics based model, which treats triton as elementary entity to make up 4214 Si28. We show here how this QCD based model is able to provide a consistent physical understanding of simultaneity of magicity/sphericity and strong deformation of a single nucleus. This brings in an essential duality in the structure of 4214 Si28 and subsequently also that of 4820 Ca28 We also provide consistent understanding of the puzzling radii of calcium isotopes. We predict that the radius of 54 Ca should be even bigger than that of 52 Ca; and also that the radius of 60 Ca should be the same as that of 40 Ca. In addition we also show wherefrom arises the neutron E2 effective charge of 12.