Heavy-strange meson decay constants in the continuum limit of quenched QCD

TL;DR

This study refines the calculation of heavy-strange meson decay constants in quenched QCD by using finer lattice resolution and improved techniques, resulting in a precise estimate of F_{B_s} at the physical b-quark mass.

Contribution

It provides an improved continuum limit extrapolation of decay constants in quenched QCD with detailed error control and a refined estimate at the b-quark mass.

Findings

F_{B_s} = 193(7) MeV at the b-quark mass

Decay constants follow the 1/m-expansion trend

Enhanced techniques reduce statistical and systematic errors

Abstract

We improve a previous quenched result for heavy-light pseudoscalar meson decay constants with the light quark taken to be the strange quark. A finer lattice resolution (a ~ 0.05 fm) in the continuum limit extrapolation of the data computed in the static approximation is included. We also give further details concerning the techniques used in order to keep the statistical and systematic errors at large lattice sizes L/a under control. Our final result, obtained by combining these data with determinations of the decay constant for pseudoscalar mesons around the D_s, follows nicely the qualitative expectation of the 1/m-expansion with a (relative) 1/m-term of about -0.5 GeV/m_PS. At the physical b-quark mass we obtain F_{B_s} = 193(7) MeV, where all errors apart from the quenched approximation are included.