Inverse Mass Expansion of the One-Loop Effective Action

TL;DR

This paper introduces a new asymptotic series expansion method for the one-loop effective action in quantum field theory, applicable to particles with non-degenerate masses, generalizing the Schwinger-DeWitt expansion.

Contribution

It develops a novel inverse mass expansion technique for the one-loop effective action that maintains chiral invariance and extends previous equal-mass expansions.

Findings

Derived the series up to fifth order coefficients

Established relationship with Seeley-DeWitt coefficients

Generalized the Schwinger-DeWitt expansion for non-degenerate masses

Abstract

A method is described for the development of the one-loop effective action expansion as an asymptotic series in inverse powers of the fermion mass. The method is based on the Schwinger-DeWitt proper-time technique, which allows for loop particles with non-degenerate masses. The case with SU(2)xSU(2) as the symmetry group is considered. The obtained novel series generalizes the well-known Schwinger-De Witt inverse mass expansion for equal masses, and is chiral invariant at each order. We calculate the asymptotic coefficients up to fifth order and clarify their relationship with the standard Seeley-DeWitt coefficients.