Baryon chiral perturbation theory with virtual photons and leptons

TL;DR

This paper develops a comprehensive relativistic baryon chiral perturbation theory framework for pion-nucleon interactions, incorporating virtual photons and leptons explicitly up to fourth order.

Contribution

It introduces a novel SU(2) Lagrangian that explicitly includes light leptons and virtual photons as dynamical degrees of freedom in baryon chiral perturbation theory.

Findings

Constructed the pion-nucleon SU(2) Lagrangian with leptons and photons.

Extended the theory to fourth order in the chiral expansion.

Provided new building blocks for including leptons dynamically.

Abstract

We construct the general pion-nucleon SU(2) Lagrangian including both virtual photons and leptons for relativistic baryon chiral perturbation theory up to fourth order. We include the light leptons as explicit dynamical degrees of freedom by introducing new building blocks which represent these leptons.