Electromagnetic and strong isospin-breaking corrections to the muon g-2 from lattice QCD+QED

Abstract

We present a lattice calculation of the leading-order electromagnetic and strong isospin-breaking corrections to the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon. We employ the gauge configurations generated by the European Twisted Mass Collaboration with Nf=2+1+1 dynamical quarks at three values of the lattice spacing (a≃0.062,0.082,0.089 fm) with pion masses between ≃210 and ≃450 MeV. The results are obtained by adopting the RM123 approach in the quenched-QED approximation, which neglects the charges of the sea quarks. Quark disconnected diagrams are not included. After the extrapolations to the physical pion mass and to the continuum and infinite-volume limits the contributions of the light, strange, and charm quarks are, respectively, equal to δaμHVP(ud)=7.1(2.5)×10-10, δaμHVP(s)=-0.0053(33)×10-10, and δaμHVP(c)=0.0182(36)×10-10. At leading order in αem and (md-mu)/ΛQCD we obtain δaμHVP(udsc)=7.1(2.9)×10-10, which is currently the most accurate determination of the isospin-breaking corrections to aμHVP.