Scaling and Further Tests of Heavy Meson Decay Constant Determinations from Nonrelativistic QCD

TL;DR

This study computes B_s and D_s meson decay constants using lattice QCD with NRQCD and clover quarks across multiple lattice spacings, analyzing scaling behavior and consistency between different meson states.

Contribution

It provides new lattice QCD results for heavy meson decay constants with detailed scaling analysis and discusses power law cancellation in NRQCD formulations.

Findings

f_{B_s} = 187(4)(4)(11)(2)(7)(6) MeV

f_{D_s} = 223(6)(31)(38)(23)(9)(^{+3}_{-1}) MeV

Demonstrated scaling and consistency in decay constant calculations.

Abstract

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.