A precise determination of the decay constant of the Ds-meson in quenched QCD

We present a lattice determination of the leptonic decay constant FDs of the Ds-meson using its mass and FK as experimental input. Setting the scale with FK=160 MeV, our final result is FDs=252(9) MeV. The error contains all uncertainties apart from the quenched approximation. Setting the scale with the nucleon mass instead leads to an decrease of 20(1) MeV of the leptonic decay constant.