Pion and kaon physics with improved staggered quarks

TL;DR

This paper presents lattice QCD calculations of pseudoscalar meson masses and decay constants using improved staggered quarks, incorporating taste-symmetry violations and chiral perturbation theory to extract fundamental parameters.

Contribution

It introduces an improved staggered quark approach with detailed chiral fits to determine meson properties and quark masses from lattice simulations.

Findings

Successful calculation of $f_$ and $f_K$

Observation of chiral logarithms in data

Extraction of Gasser-Leutwyler parameters and quark masses

Abstract

We compute pseudoscalar meson masses and decay constants using staggered quarks on lattices with three flavors of sea quarks and lattice spacings $\approx 0.12$ fm and $\approx 0.09$ fm. We fit partially quenched results to ``staggered chiral perturbation theory'' formulae, thereby taking into account the effects of taste-symmetry violations. Chiral logarithms are observed. From the fits we calculate $f_\pi$ and $f_K$, extract Gasser-Leutwyler parameters of the chiral Lagrangian, and (modulo rather large perturbative errors) find the light and strange quark masses.