The masses of the mesons and baryons. Part II. The Standing Wave Model
  In order to explain the empirical integer multiple rule for the stable mesons and baryons presented in the preceding paper we assume that the particles are held together in a cubic nuclear lattice. This is a novel approach to the particles, based on the fact that the range of the weak nuclear force is only a thousandth of the diameter of the nucleon, and that the crystals are the best-known macroscopic bodies held together by a microscopic force. We investigate the standing waves in a cubic nuclear lattice. From the frequency distribution of the waves follows that the masses of the $\gamma$-branch particles are integer multiples of $m(\pi^0)$. We show that each particle has automatically an antiparticle. Assuming that the energy of the oscillations is determined by Planck's formula for the energy of a linear oscillator, it turns out that the $\pi^0$ meson and the other members of the $\gamma$-branch are like cubic black bodies filled with plane, standing electromagnetic waves. Our standing wave model explains the integer multiple rule of the masses of the neutral mesons and baryons of the $\gamma$-branch and uses nothing else but photons. Our results justify the cubic lattice assumption. 
E. L. Koschmieder and T. H. Koschmieder