Electromagnetic low-energy constants in ChPT

TL;DR

This paper studies the electromagnetic low-energy constants in three-flavour chiral perturbation theory, focusing on the strange quark mass dependence and its implications for more precise determinations.

Contribution

It derives the strange quark mass dependence of electromagnetic low-energy constants in a specific chiral perturbation theory limit, enhancing precision in their determination.

Findings

Derived relations for strange quark mass dependence of low-energy constants

Provided formulas useful for experimental and theoretical analyses

Improved understanding of electromagnetic effects in chiral perturbation theory

Abstract

We investigate three-flavour chiral perturbation theory including virtual photons in a limit where the strange quark mass is much larger than the external momenta and the up and down quark masses, and where the external fields are those of two-flavour chiral perturbation theory. In particular we work out the strange quark mass dependence of the electromagnetic two-flavour low-energy constants C and k_i. We expect that these relations will be useful for a more precise determination of the electromagnetic low-energy constants.