Decay constants of charm and beauty pseudoscalar heavy-light mesons on fine lattices

We compute decay constants of heavy-light mesons in quenched lattice QCD with a lattice spacing of a≃0.04fm using non-perturbatively O(a) improved Wilson fermions and O(a) improved currents. We obtain fDs=220(6)(5)(11)MeV, fD=206(6)(3)(22)MeV, fBs=205(7)(26)(17)MeV and fB=190(8)(23)(25)MeV, using the Sommer parameter r0=0.5fm to set the scale. The first error is statistical, the second systematic and the third from assuming a ±10% uncertainty in the experimental value of r0. A detailed discussion is given in the text. We also present results for the meson decay constants fK and fπ and the ρ meson mass.