%0 Journal Article
%A Fodor, Z.
%A Hoelbling, C.
%A Krieg, S.
%A Lellouch, L.
%A Lippert, Th.
%A Portelli, A.
%A Sastre, A.
%A Szabo, Kalman
%A Varnhorst, L.
%T Up and Down Quark Masses and Corrections to Dashen’s Theorem from Lattice QCD and Quenched QED
%J Physical review letters
%V 117
%N 8
%@ 1079-7114
%C College Park, Md.
%I APS
%M FZJ-2016-04440
%P 082001
%D 2016
%X In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on Nf=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen’s theorem and the individual up and down quark masses. Our ensembles include 5 lattice spacings down to 0.054 fm, 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 Dashen’s theorem, we obtain ϵ=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) and md=4.67(6)(5)(4)  MeV in the modified minimal subtraction scheme at 2  GeV 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000381495100005
%$ pmid:27588847
%R 10.1103/PhysRevLett.117.082001
%U https://juser.fz-juelich.de/record/817800