We present a determination of the corrections to Dashen's theorem and of the individual up and down quark masses from a lattice calculation based on quenched QED and Nf = 2+1 QCD simulations with 5 lattice spacings down to 0.054 fm. The simulations feature lattice sizes up to 6 fm and average up-down quark masses all the way down to their physical value. For the parameter which quantifies violations to Dashens's theorem we obtain e =0:73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light quark masses we obtain, mu = 2:27(6)(5)(4)MeV and md = 4:67(6)(5)(4)MeV in the MS scheme at 2GeV and the isospin breaking ratios mu=md = 0:485(11)(8)(14), R = 38:2(1:1)(0:8)(1:4) and Q = 23:4(0:4)(0:3)(0:4). Our results exclude the mu = 0 solution to the strong CP problem by more than 24 standard deviations.
|Journal||Proceedings of Science|
|Publication status||Published - Jan 1 2016|
|Event||34th Annual International Symposium on Lattice Field Theory, LATTICE 2016 - Southampton, United Kingdom|
Duration: Jul 24 2016 → Jul 30 2016
ASJC Scopus subject areas