Results for light pseudoscalars from three-flavor simulations

MILC Collaboration; C. Aubin; C. Bernard; C. DeTar; Steven Gottlieb; E. B. Gregory; Urs M. Heller; J. E. Hetrick; J. Osborn; R. L. Sugar; D. Toussaint

doi:10.1016/j.nuclphysbps.2004.11.174

paper

Results for light pseudoscalars from three-flavor simulations

arXiv:hep-lat/0409041 · doi:10.1016/j.nuclphysbps.2004.11.174

Abstract

We compute pseudoscalar meson masses and decay constants in partially quenched QCD with three dynamical flavors of improved staggered quarks. Fitting the lattice data to staggered chiral perturbation theory forms and extrapolating in quark mass and lattice spacing, we find: $f_{I ¨} = 129.5 \pm 0.9 \pm 3.5$ MeV, $f_{K} = 156.6 \pm 1.0 \pm 3.6$ MeV, and $f_{K} / f_{I ¨} = 1.210 (4) (13)$ . The value for $f_{K} / f_{I ¨} $ implies $∣ V_{u s} ∣ = 0.2219 (26)$ . We also obtain $m_{u} / m_{d} = 0.43 (0) (1) (8)$ , or, with more input on electromagnetic effects from the continuum, $m_{u} / m_{d} = 0.41 (0) (1) (4)$ . Using the one-loop perturbative mass renormalization, we determine $m_{u}$ and $m_{d}$ in the MSbar scheme.

Talk presented at Lattice2004(spectrum), Fermilab, June 21 - 26, 2004; 3 pages, 2 figures