TY - JOUR

T1 - Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED

AU - Budapest-Marseille-Wuppertal Collaboration

AU - Fodor, Z.

AU - Hoelbling, C.

AU - Krieg, S.

AU - Lellouch, L.

AU - Lippert, Th

AU - Portelli, A.

AU - Sastre, A.

AU - Szabo, K. K.

AU - Varnhorst, L.

N1 - Publisher Copyright:
© 2016 American Physical Society.

PY - 2016/8/15

Y1 - 2016/8/15

N2 - 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 μ=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.

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 μ=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.

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U2 - 10.1103/PhysRevLett.117.082001

DO - 10.1103/PhysRevLett.117.082001

M3 - Article

AN - SCOPUS:84985028198

SN - 0031-9007

VL - 117

JO - Physical review letters

JF - Physical review letters

IS - 8

M1 - 082001

ER -