Covariant propagator and chiral power counting

TL;DR

This paper demonstrates that using covariant baryon propagators in chiral effective theory simplifies the maintenance of chiral power counting by removing the need for extra operations, ensuring stable leading corrections and threshold effects.

Contribution

It shows that subtracting local terms violating chiral power counting suffices when using covariant propagators, eliminating the need for additional procedures.

Findings

Chiral power counting can be restored by subtracting local terms.

Covariant propagators preserve the structure of leading corrections.

Threshold effects remain stable with covariant propagators.

Abstract

Some one-loop diagrams with one and two external baryons/nucleons are revisited using covariant baryon propagators in chiral effective theory. We showed that it is enough to separate and subtract all the local terms that violate chiral power counting to recover chiral power counting, no need to introduce extra operations. The structures of leading chiral corrections and IR enhancement or threshold effects are 'stable' or persist as long as covariant propagators are employed for all particles.