In the periodic table, a Hydrogen nucleus has one proton and a Helium nucleus has two protons but in addition, it also has two neutrons and no-one knows why. Higher elements have even more neutrons and what those extra neutrons do is a mystery:
“… all the stable nuclei have more neutrons than protons (or equal numbers), and the heavier nuclei are increasingly neutron-rich.” (Marburger, 2011) p254
For some reason, heavier nuclei need more neutrons to be stable (Figure 4.22) until in Uranium, proton repulsion breaks apart the nucleus in nuclear radiation. There is currently no theory that explains the neutron’s role in keeping the nucleus stable. The shell model used to explain electrons doesn’t work because some nuclei aren’t spherical. The standard model doesn’t help because if gluons are holding the protons together, why have neutrons? And how do the gluons know how many neutrons are needed to stabilize a heavy nucleus ?
The quark structure described earlier sheds light on the issue as it describes protons and neutrons as quarks linking in a closed triangle. It follows that such triangles can open up and recombine in longer quark strings if the same rules are satisfied: namely a closed shape with the internal angles of an equilateral triangle.
In this view, a Helium nucleus is not two protons and two neutrons sitting separately together, like fruit in a bowl. It is the quarks of two protons and two neutrons linking by photon sharing to form a single string that closes back on itself.
So it is quite incorrect to envisage a Helium nucleus as separate proton and neutron particles sitting side-by-side with gluons somehow forcing the protons together. Instead, the Helium nucleus is a single quark string held together by photon sharing, just as protons and neutrons are. Higher nuclei are then bound just as protons are, by photon sharing. The only restriction is that each link must bend the string 60º which requires quarks to rotate to make a connection.
That this configuration arises dynamically then explains why neutrons are needed. Since photon sharing needs direct proximity, a proton is unlikely to come that close to another proton because they repel so neutrons are needed to link to the protons. When forming a quark string, neutrons act as string buffers in between same-charge protons that repel when side-by-side. This requires at least as many neutrons as protons, as observed. Hence Helium with a two-proton string ideally needs two neutrons to act as buffers between the two protons in a string.
Folded quark strings will be compact and nearly spheres, as observed, but larger nuclei may need more neutrons to avoid fold-back loci that happen to make protons adjacent. In this nuclear evolution certain shapes will be more stable:
“Nuclei with either protons or neutron equal to certain “magic” numbers (2, 8, 20, 28, 50, 82, 126) are particularly stable.” (Marburger, 2011) p253
If atomic nuclei are folded quark strings, those with a “magic” number of nucleons will be more stable because they form the symmetric shapes that gave rise to magic numbers in the first place. A quark string model explains the properties of atomic nuclei and the role neutrons play in their creation. In quantum realism, nuclei are single 3D shapes that fold in space as proteins do.