%0 Conference Paper
%A Varnhorst, L.
%A Durr, S.
%A Fodor, Z.
%A Hoelbling, C.
%A Krieg, S.
%A Lellouch, L.
%A Portelli, A.
%A Sastre, A.
%A Szabo, Kalman
%T Up and down quark masses and corrections to Dashen's theorem from lattice QCD and quenched QED
%V LATTICE2016
%@ 1824-8039
%C Trieste
%I SISSA
%M FZJ-2017-01490
%B Proceedings of Science LATTICE2016 200
%P 200
%D 2017
%X 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 $N_f =2+1$ 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 $\epsilon=0.73(2)(5)(17)$, 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, $m_u=2.27(6)(5)(4) \, MeV$ and $m_d=4.67(6)(5)(4) \, MeV$ in the $\overline{MS}$ scheme at $2 \, GeV$ and the isospin breaking ratios $m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and $Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong CP problem by more than 24 standard deviations.
%B 34th annual International Symposium on Lattice Field Theory
%C 24 Jul 2016 - 30 Jul 2016, Southampton (UK)
Y2 24 Jul 2016 - 30 Jul 2016
M2 Southampton, UK
%F PUB:(DE-HGF)8 ; PUB:(DE-HGF)7
%9 Contribution to a conference proceedingsContribution to a book
%U https://juser.fz-juelich.de/record/827319