Quantum Field Theory Beyond the S-Matrix Formalism

Abstract

Particle transitions passing over finite space and time intervals are self-consistently described within a novel quantum field-theoretical approach based on Feynman diagrams in configuration space. The transition to momentum space is performed following the rules modified so as to consider the geometry of neutral-meson and neutrino oscillation experiments. Using the processes of decay of an unstable scalar particle at a macroscopic distance from the source and of neutral kaon and neutrino oscillations as examples, we demonstrate that their known characteristics are adequately reproduced within the proposed approach.