Theory of the Elementary Particles
  Lattice theory is used to explain the rest masses of the stable mesons and baryons and their spin. From the mass of the charged pi-mesons follows the mass of the muons. From the mass of the muons follows the mass of the electron. We do not use hypothetical particles. Only photons, neutrinos and charge are needed to explain the mass of the elementary particles. 
E. L. Koschmieder