Determination of light and strange quark masses from two-flavour dynamical lattice QCD

We compute the light and strange quark masses mℓ=(mu+md)/2 and ms, respectively, in unquenched lattice QCD with Nf=2 flavours of light dynamical quarks. The renormalisation constants, which convert bare quark masses into renormalised quark masses, are computed nonperturbatively, including the effect of quark-line disconnected diagrams. We obtain mℓMS¯(2 GeV)=4.7(2)(3) MeV and msMS¯(2 GeV)=119(5)(8) MeV, using r0=0.467 fm to set the scale.