Update on pi and K Physics

TL;DR

This paper updates MILC's light pseudoscalar physics studies using improved staggered fermions, incorporating new data and analyses to refine decay constants and test staggered chiral perturbation theory across different lattice spacings.

Contribution

It provides new results for decay constants with lighter quark masses and tests staggered chiral perturbation theory in quenched lattice QCD at multiple spacings.

Findings

Improved decay constant measurements with lighter quarks.

Validation of staggered chiral perturbation theory across lattice spacings.

Enhanced statistical accuracy in light pseudoscalar analyses.

Abstract

We present an update of the MILC studies of the physics of light pseudoscalars using improved staggered fermions. New runs at lighter quark mass, as well as increased statistics for older sets, are enabling us to improve the results for decay constants in full QCD. In addition, we have analyzed quenched runs at two different lattice spacings. This makes possible a test of the applicability of staggered chiral perturbation theory in a different context.