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

Abstract

We compute the strange quark mass $m_s$ and the average of the $u$ and $d$ quark masses $\hat{m}$ using full lattice QCD with three dynamical quarks combined with experimental values for the pion and kaon masses. The simulations have degenerate $u$ and $d$ quarks with masses $m_u=m_d\equiv \hat{m}$ as low as $m_s/8$, and two different values of the lattice spacing. The bare lattice quark masses obtained are converted to the $\text{msbar}$ scheme using perturbation theory at $O(alph{a}_s)$. Our results are: $m_s^{\text{msbar}}$(2 GeV) = 76(0)(3)(7)(0) MeV, ${\hat{m}}^{\text{msbar}}$(2 GeV) = 2.8(0)(1)(3)(0) MeV and $m_s/\hat{m}$ = 27.4(1)(4)(0)(1), where the errors are from statistics, simulation, perturbation theory, and electromagnetic effects, respectively.

Comments: 5 pages, revtex, 2 figures. v2: New ms/hat(m) discussion and reference, v3: slight change in discussion of reference