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

TL;DR

This paper reports a lattice QCD calculation of strange and charm quark contributions to the muon g-2, including electromagnetic corrections, using twisted-mass fermions and physical quark masses.

Contribution

It provides the first lattice QCD results for strange and charm HVP contributions to muon g-2 with QED corrections at physical quark masses.

Findings

Strange quark contribution: (53.1 ± 2.5)×10⁻¹⁰

Charm quark contribution: (14.75 ± 0.56)×10⁻¹⁰

Electromagnetic corrections are included in the calculation.

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 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.