We present results for the B_s meson decay constant f_{ B_s} from simulations at three lattice spacings in the range a^{ -1}=1.1 to 2.6 GeV using NRQCD heavy quarks and clover light quarks in the quenched approximation. We study scaling of this quantity and check the consistency between mesons decaying from rest and from a state with nonzero spatial momentum. The cancellation of power law contributions that arise in the NRQCD formulation of heavy-light currents is discussed. On the coarsest lattice the D_s meson decay constant f_{ D_s} is calculated. Our best values for the decay constants are given by f_{ B_s} = 187(4)(4)(11)(2)(7)(6) MeV and f_{ D_s} = 223(6)(31)(38)(23)(9)(^{ +3}_{ -1}) MeV.
Categories: hep-lat