Quark Model of Nucleus

Abstract

The had structure and strong interactions. When studying the nucleon-nucleon scattering and structure of atomic nuclei in the ground and excited states, we everywhere have treated nucleons as point-like structureless particles. In fact, nucleons have finite and comparatively large dimensions, which are of the order of a radius of the nuclear (nucleon-nucleon) forces. It has long been indicated by some facts, for example, the results of the scattering of ultra-relativistic electrons by protons and complex nuclei in the Hofstadter experiments in 50’s and the consequent experiments. In particular, to describe the observed electron-proton scattering it was necessary to introduce the proton charge distribution form-factor (see (3.4)), (as well as for the complex nuclei), which gave the mean square (electromagnetic) proton radius R _p ≈ 0.8 X 10^-13 cm¹. It is worth noting that at low (nonrelativistic) energies of nucleons, particularly in nuclei, the proper nucleon structure manifests itself rather weakly. Thus, the approximation of point-like nucleons used in all the previous sections of this book seems to be justified. In part it is associated with the fact that all complex nuclei are comparatively weakly bound nucleon systems, where the mean distance between nucleons is considerably larger than the nucleon dimensions. Therefore, we can expect that in many cases the proper nucleon structure effect may emerge as small corrections in the nuclear properties and nuclear processes at low energies.