Speaker
Description
In the current determination of the muon g-2, the hadronic vacuum polarization (HVP) contribution⸺which dominates the theoretical uncertainty⸺is evaluated as an average of different lattice QCD calculations. Since lattice simulations are mostly carried out in isospin symmetric QCD, corrections due to the mass difference of the up and down quarks (strong IB) and the coupling to photons (QED corrections) have to be taken into account. These isospin breaking (IB) corrections are one of the major sources of uncertainty.
I present the current calculation of the IB corrections to the HVP contribution at physical pion mass for the RBC/UKQCD collaborations. We employ the RM123 approach using stochastic coordinate sampling of the all-to-all propagator to evaluate the QED corrections in the QED_L prescription, where also including tadpole contributions. For the connected strong isospin breaking corrections, we compute mass derivatives of the leading connected contribution using multiple different valence quark masses. We determine the shift of the up, down and strange quark masses, by fixing the mass of the neutral pion and kaon and the kaon mass splitting.