Staggered chiral perturbation theory in the two-flavor case

TL;DR

This paper develops a detailed two-flavor staggered chiral perturbation theory framework, deriving relations and calculations for pion properties, aiding lattice QCD data analysis with varying strange quark masses.

Contribution

It derives the SU(2) staggered chiral theory from the SU(3) case and provides explicit relations between low energy constants and taste-violating parameters.

Findings

Derived pion mass and decay constant at NLO for partially-quenched case.

Showed SU(2) theory emerges from SU(3) in the large strange quark mass limit.

Provided relations between SU(2) and SU(3) low energy constants.

Abstract

I study two-flavor staggered chiral perturbation theory in the light pseudoscalar sector. The pion mass and decay constant are calculated through NLO in the partially-quenched case. In the limit where the strange quark mass is large compared to the light quark masses and the taste splittings, I show that the SU(2) staggered chiral theory emerges from the SU(3) staggered chiral theory, as expected. Explicit relations between SU(2) and SU(3) low energy constants and taste-violating parameters are given. The results are useful for SU(2) chiral fits to asqtad data and allow one to incorporate effects from varying strange quark masses.