On the Charge Independence of Nuclear Forces

Abstract

It is shown that the small difference between the neutron-proton and proton-proton interactions in the ${}_{}{}^1{}_{}{}^{}S$ state can be accounted for by magnetic forces, provided the nuclear interaction is described by the Yukawa potential. A variational principle is used to facilitate the comparison of the interactions, and for the determination of the effect of magnetic forces. A short discussion of variational principles is presented in the Appendix.