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 - Funding Information:
This work was supported in part by the OCEVU Laboratoire d'excellence (ANR-11-LABX-0060) and the A?MIDEX Project (ANR-11-IDEX-0001-02) which are funded by the Investissements d'Avenir French government program and managed by the Agence nationale de la recherche (ANR), by CNRS Grants No. GDR No. 2921 and PICS No. 4707, by EU Grants FP7/2007-2013/ERC No. 208740, MRTN-CT-2006-035482 (FLAVIAnet), by DFG Grants No. FO 502/2, SFB TRR-55 and UK STFC Grants No. ST/L000296/1 and ST/L000458/1. L.V. was partially supported by a GSI grant.

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

VL - 117

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 8

M1 - 082001

ER -