HVP contributions to the muon ($g - 2$) including QED corrections with twisted-mass fermions

TL;DR

This paper presents a lattice QCD calculation of the strange and charm quark contributions to the muon's anomalous magnetic moment, including electromagnetic corrections, with results extrapolated to physical pion mass and continuum limit.

Contribution

It provides the first lattice QCD determination of HVP contributions to muon g-2 including QED corrections for strange and charm quarks at multiple lattice spacings.

Findings

Strange quark contribution: (53.1 ± 2.5) × 10^{-10}

Charm quark contribution: (14.75 ± 0.56) × 10^{-10}

Electromagnetic corrections are quantified for both quark flavors.

Abstract

We present a lattice calculation of the Hadronic Vacuum Polarization (HVP) contribution of the strange and charm quarks to the anomalous magnetic moment of the muon including leading-order electromagnetic (e.m.) corrections. We employ the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with $N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a \simeq 0.062, 0.082, 0.089$ fm) with pion masses in the range $M_\pi \simeq 210 - 450$ MeV. The strange and charm quark masses are tuned at their physical values. Neglecting disconnected diagrams and after the extrapolations to the physical pion mass and to the continuum limit we obtain: $a_\mu^s(\alpha_{em}^2) = (53.1 \pm 2.5) \cdot 10^{-10}$, $a_\mu^s(\alpha_{em}^3) = (-0.018 \pm 0.011) \cdot 10^{-10}$ and $a_\mu^c(\alpha_{em}^2) = (14.75 \pm 0.56) \cdot 10^{-10}$, $a_\mu^c(\alpha_{em}^3) = (-0.030 \pm 0.013) \cdot 10^{-10}$ for the strange and charm contributions, respectively.