First determination of the strange and light quark masses from full lattice QCD

We compute the strange quark mass mₛ and the average of the u and d quark masses m ̂ \^ using full lattice QCD with three dynamical quarks combined with the experimental values for the π and K masses. The simulations have degenerate u and d quarks with masses mᵤ=md≡m ̂ \^ as low as mₛ/8, and two different values of the lattice spacing. The bare lattice quark masses obtained are converted to the MS̄ scheme using perturbation theory at O(αS). Our results are mₛMS̄(2GeV)=76(0)(3)(7)(0)MeV, mMS̄(2GeV)=2.8(0)(1)(3)(0) MeV, and mₛ/m ̂ \^=27.4(1)(4)(0)(1), where the errors are from statistics, simulation, perturbation theory, and electromagnetic effects, respectively.