On the Methods for Constructing Meson-Baryon Reaction Models within Relativistic Quantum Field Theory

TL;DR

This paper compares three different relativistic quantum field theory methods for constructing meson-baryon reaction models, analyzing their differences and relations to S-matrix dispersion approaches.

Contribution

It provides a detailed comparison of three prominent methods for meson-baryon reaction modeling within relativistic quantum field theory.

Findings

Identifies key differences between the methods.

Discusses the relation to S-matrix dispersion relations.

Provides insights into the applicability of each approach.

Abstract

Within the relativistic quantum field theory, we analyze the differences between the $\pi N$ reaction models constructed from using (1) three-dimensional reductions of Bethe-Salpeter Equation, (2) method of unitary transformation, and (3) time-ordered perturbation theory. Their relations with the approach based on the dispersion relations of S-matrix theory are dicusssed.