New Constraints on Quantum Theories

Hierarchical relationships between physical theories are discussed. It is explained how a lower rank theory imposes constraints on an acceptable structure of its higher rank theory. This principle is applied to the case of quantum mechanics and quantum eld theory of massive particles. It is proved that the Dirac equation is consistent with these constraints whereas the Klein-Gordon equation, as well as all other second order quantum equations are inconsistent with the Schrodinger equation. This series of arguments ¨ undermines the theoretical structure of the Standard Model.