Speaker
Miguel Teseo San José Pérez
(IJCLab)
Description
We employ $N_\mathrm{f}=2+1$ flavours of $O(a)$ improved Wilson fermions to determine the hadronic vacuum polarisation functions $\bar{\Pi}^{\gamma\gamma}$ and $\bar{\Pi}^{\gamma Z}$ for Euclidean squared momenta $Q^2\leq 7$ $\mathrm{GeV}^2$. We extrapolate the results to the physical point using ensembles at four lattice spacings and several pion masses, including its physical value. We observe a tension of up to 3.5 standard deviations between our lattice results for $\Delta\alpha_\mathrm{had}^{(5)}(-Q^2)$ and estimates based on the $R$-ratio for space-like momenta in the range $3-7~\mathrm{GeV}^2$.
Primary authors
Andreas Risch
(DESY, NIC)
Miguel Teseo San José Pérez
(IJCLab)
Antoine Gérardin
(Aix-Marseille-Universit ́e, Universit ́e de Toulon, CNRS, CPT, Marseille, France)
Georg von Hippel
(JGU Mainz)
Hartmut Wittig
Harvey B. Meyer
(Johannes Gutenberg University Mainz)
Jonas Wilhelm
Kohtaroh Miura
(Helmholtz-Institut Mainz, Johannes Gutenberg-Universit ̈at Mainz, Germany)
Konstantin Ottnad
(University of Mainz)
Marco Cè
(AEC and ITP, Universität Bern)
