TY  - JOUR
AU  - Fodor, Z.
AU  - Hoelbling, C.
AU  - Krieg, S.
AU  - Lellouch, L.
AU  - Lippert, Th.
AU  - Portelli, A.
AU  - Sastre, A.
AU  - Szabo, Kalman
AU  - Varnhorst, L.
TI  - Up and Down Quark Masses and Corrections to Dashen’s Theorem from Lattice QCD and Quenched QED
JO  - Physical review letters
VL  - 117
IS  - 8
SN  - 1079-7114
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2016-04440
SP  - 082001
PY  - 2016
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000381495100005
C6  - pmid:27588847
DO  - DOI:10.1103/PhysRevLett.117.082001
UR  - https://juser.fz-juelich.de/record/817800
ER  -