Masses and decay constants of pions and kaons in mixed-action staggered chiral perturbation theory

TL;DR

This paper computes pion and kaon masses and decay constants using mixed-action staggered chiral perturbation theory at next-to-leading order, aiding lattice QCD studies with different valence and sea quark actions.

Contribution

It extends staggered chiral perturbation theory to mixed-action setups, providing formulas for masses and decay constants across all tastes at NLO.

Findings

Results reduce to known cases when valence and sea actions are identical.

Provides smooth connection to the continuum limit.

Helps control discretization errors in lattice QCD calculations.

Abstract

Lattice QCD calculations with different staggered valence and sea quarks can be used to improve determinations of quark masses, Gasser-Leutwyler couplings, and other parameters relevant to phenomenology. We calculate the masses and decay constants of flavored pions and kaons through next-to-leading order in staggered-valence, staggered-sea mixed-action chiral perturbation theory. We present the results in the valence-valence and valence-sea sectors, for all tastes. As in unmixed theories, the taste-pseudoscalar, valence-valence mesons are exact Goldstone bosons in the chiral limit, at non-zero lattice spacing. The results reduce correctly when the valence and sea quark actions are identical, connect smoothly to the continuum limit, and provide a way to control light quark and gluon discretization errors in lattice calculations performed with different staggered actions for the valence and sea quarks.