On the Electromagnetic Structure of Nucleons and Their Mass Difference

Abstract

A semi-phenomenological methodology is proposed for the study of the structures of elementary particles based on the problem of the electromagnetic structure of nucleons. It is convenient to separate the analyses of structure into two parts. One is the analysis of the outer structure which is characterized as the quasi-short distance and defined by r es sufficiert t 0.5y. Though the present field theory could be applied in this region, it is shown that the shape-independent feature also holds in so far as the present experimental information is concerned. The other is the presumption of the inner structure of the extreme short distance. A physical quantity which is effective in the analysis of this region can be extracted by using a proposed trial model in harmony with the present experiments. A presumption comes from the electromagnetic mass difference of nucleons. The analyses are devoted to three effects: i) change of the form factors at the extreme short distance, ii) neutron charge fornn factor, and iii) higher order corrections of the strong interactions. These effects have qualitatively good points for the explanation of the mase difference. A small raodification of the inner structure is especially quantitatively suitable to explain the experimentalmore » value. (auth)« less