20 03 Why Is Cpt Fundamental ?

G. Lüders and W. Pauli proved the CPT theorem based on Lagrangian quantum field theory almost half a century ago. R. Jost gave a more general proof based on " axiomatic " field theory nearly as long ago. The axiomatic point of view has two advantages over the Lagrangian one. First, the ax-iomatic point of view makes clear why CPT is fundamental–because it is intimately related to Lorentz invariance. Secondly, the axiomatic proof gives a simple way to calculate the CPT transform of any relativistic field without calculating C, P and T separately and then multiplying them. The purpose of this pedagogical paper is to " deaxiomatize " the CPT theorem by explaining it in a few simple steps. We use theorems of distribution theory and of several complex variables without proof to make the exposition elementary.