Light pseudoscalar meson masses and decay constants from mixed action lattice QCD
Abstract
We calculate the light pseudoscalar decay constants, fpi and fK, and their ratio using domain wall valence quarks and 2+1 flavors of dynamical staggered quarks. Use of the MILC gauge configurations allows us to simulate at several sea quark masses and spatial volumes, and with two lattice spacings. We study how well our numerical lattice data for light decay constants and meson masses is described by next-to-leading order SU(3) mixed action chiral perturbation theory and explain our strategy for the chiral and continuum extrapolation. Combining our result for fK/fpi with experimental measurements of pion and kaon leptonic decays allows a model-independent determination of |Vus|/|Vud|; we find a preliminary value of |Vus|/|Vud| = 0.2315(45)(7).