Systematic Spurion Matching between Low Energy EFT and Chiral Lagrangian

TL;DR

This paper introduces a systematic method for matching low energy effective field theory operators to the chiral Lagrangian using a single spurion field, simplifying the process without external sources.

Contribution

It develops a complete set of LEFT operators up to dimension 9 reformulated with a single spurion, streamlining the matching to the chiral Lagrangian.

Findings

Complete LEFT operators reformulated with a single spurion.

Matching procedure performed using flavor $SU(3)_V$ and $CP$ structures.

Simplified the chiral Lagrangian formulation without external sources.

Abstract

The hadronic chiral Lagrangian can be matched from the low energy effective field theory (LEFT) operators at the quark level. Traditionally, as the mass dimension of the LEFT operators increases, more and more external sources are necessarily introduced in the chiral perturbation theory (ChPT). In this work, we present a systematic matching procedure with the single spurion field $\mathbf{T}$ of the flavor $SU(3)_V$ octet, without the need of external sources. We present the complete sets of the LEFT operators, which have been reformulated using the flavor $SU(3)_V$ symmetry up to dimension 9. At the same time, the ChPT Lagrangian is also reformulated using the single spurion and lepton fields, instead of external sources. The spurion matching can be performed between LEFT and ChPT operators with the same flavor $SU(3)_V$ and $CP$ structures, and the same leptonic currents, using the naive dimensional analysis at the quark and hadronic levels.