Quantum Field Theory of Complex Mass

Abstract

General properties of a complex massed particle are studied. The microcausality is reconsidered briefly and the macrocausality in our sense is defined in a very simple way. It is then examined whether a particle with a complex mass violates the macrocausality, and the demand not to violate the macro:::ausality gives a condition for the complex mass. The canonical quantization is applied to a field with complex mass. In this case the vacuum is defined carefully so that the propagator does not diverge in infinite past and future. A new propagator which eliminates the divergence from the usual field theory is introduced using the complex massed fields aside from the usual field with real mass. A new interpretation on the internal structure of elementary particles is suggested from this propagator and a more generalized propagator of a non-local f1eld. It is proved that the scattering matrix defined as usual is unitary in the subspace of real massed particles.