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

Abstract We present a precise determination of the leptonic decay constant F D s of the DS-meson in quenched lattice QCD. This work is particularly focused on the analysis and discussion of all sources of systematic errors. We simulate directly at the physical quark masses for five different lattice spacings between 0.1 fm and 0.03 fm using O(a) -improvement. The finest lattice is still work in progress. After taking the continuum limit and setting the scale with the Kaon decay constant F K = 160 MeV we arrive at a value of D s , = 252(9) MeV . Setting the scale with the nucleon mass instead leads to a decrease of about 20 MeV of F D in s.