Precise charm to strange mass ratio and light quark masses from full lattice QCD

Abstract

By using a single formalism to handle charm, strange and light valence quarks in full lattice QCD for the first time, we are able to determine ratios of quark masses to 1%. For $m_c/m_s$ we obtain 11.85(16), an order of magnitude more precise than the current PDG average. Combined with 1% determinations of the charm quark mass now possible this gives ${\bar{m}}_s(2\mathrm{GeV})=$ 92.4(1.5) MeV. The MILC result for $m_s/m_l=27.2(3)$ yields ${\bar{m}}_l(2\mathrm{GeV})$ = 3.40(7) MeV for the average of $u$ and $d$ quark masses.

Comments: 4 pages, 2 figures. Version accepted by Physical Review Letters. Changes include modifying the title, using the MILC value for m_s/m_l which changes slightly the resulting up and down quark masses and their average, adding some references and making other small adjustments to the text for space reasons.