Baryon chiral perturbation theory

TL;DR

This paper introduces key methods in baryon chiral perturbation theory, discussing power counting, renormalization, and applications to nucleon properties and form factors, including higher-loop calculations and unstable particles.

Contribution

It presents a comprehensive overview of advanced techniques like infrared regularization and the extended on-mass-shell scheme for baryon chiral perturbation theory, with new applications to nucleon mass expansion and form factors.

Findings

Chiral expansion of nucleon mass to order ${\

and the inclusion of vector and axial-vector mesons in form factor calculations.

Demonstration of the infrared regularization and extended on-mass-shell scheme for higher-loop calculations and additional degrees of freedom.

Abstract

We provide a short introduction to the one-nucleon sector of chiral perturbation theory and address the issue of power counting and renormalization. We discuss the infrared regularization and the extended on-mass-shell scheme. Both allow for the inclusion of further degrees of freedom beyond pions and nucleons and the application to higher-loop calculations. As applications we consider the chiral expansion of the nucleon mass to order ${\cal O}(q^6)$ and the inclusion of vector and axial-vector mesons in the calculation of nucleon form factors. Finally, we address the complex-mass scheme for describing unstable particles in effective field theory.