This article is cited in 6 papers

Quantum field theory description of processes passing at finite space and time intervals

I. P. Volobuev^a, V. O. Egorov<sup>ab

a</sup> Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
^b Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia

Abstract: We consider a new approach to the quantum field theory description of processes passing at finite space–time intervals. The formalism is based on the Feynman diagram technique in the coordinate representation supplemented with modified rules for the transition to the momentum representation reflecting specific experimental situations. This effectively implies that only the particle propagators in the momentum representation are modified, while the standard Feynman rules in the momentum representation remain unchanged. No wave packets are used in the approach, i.e., the initial and final states of particles are described by plane waves, which significantly simplifies the calculations. Three processes – neutrino oscillations, unstable particle decay, and neutral kaon oscillations – are used as examples to show that the proposed approach correctly reproduces the well-known results.

Keywords: quantum field theory, Feynman diagram technique.

Received: 05.03.2018
Revised: 07.06.2018

DOI: 10.4213/tmf9559

 English version: Theoretical and Mathematical Physics, 2019, 199:1, 562–576

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