Nuclear Magnetic Moment andj−jCoupling Shell Model

It is shown that the magnetic moment of nuclei can be explained by a refined $j-j$ coupling shell model, where neutron and proton shells are treated simultaneously, using the isotopic spin variable. The experimental moments agree well with the calculated ones for those states which have definite isotopic spin multiplicity. It is shown that a nuclear force caused by a neutral or symmetric meson is consistent with our results, but one caused by a charged meson is excluded.