Precision computation of the strange quarkʹs mass in quenched QCD Original Research Article

We determine the renormalization group invariant quark mass corresponding to the sum of the strange and the average light quark mass in the quenched approximation of QCD, using as essential input the mass of the K-mesons. In the continuum limit we find (Ms+M̂)/FK=0.874(29), which includes systematic errors. Translating this non-perturbative result into the running quark masses in the MS scheme at μ=2 GeV and using the quark mass ratios from chiral perturbation theory, we obtain ms(2 GeV)=97(4) MeV. With the help of recent results by the CP-PACS Collaboration, we estimate that a 10% higher value would be obtained if one replaced FK by the nucleon mass to set the scale. This is a typical ambiguity in the quenched approximation.