The hadronic running of the electromagnetic coupling and electroweak mixing angle
PoS(LATTICE2022)328 We present results for the hadronic running of the electromagnetic coupling and the weak mixing angle from simulations of lattice QCD with $N_f=2+1$ flavours of $O(a)$-improved Wilson fermions. Using two different discretisations of the vector current, we compute the quark-connec...
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Zusammenfassung: | PoS(LATTICE2022)328 We present results for the hadronic running of the electromagnetic coupling
and the weak mixing angle from simulations of lattice QCD with $N_f=2+1$
flavours of $O(a)$-improved Wilson fermions. Using two different
discretisations of the vector current, we compute the quark-connected and
-disconnected contributions to the hadronic vacuum polarisation (HVP) functions
$\bar{\Pi}^{\gamma\gamma}$ and $\bar{\Pi}^{Z\gamma}$ for spacelike squared
momenta $Q^2\leq 7$ $\mathrm{GeV}^2$. Our results are extrapolated to the
physical point using ensembles at four lattice spacings, with pion masses
ranging from 130 to 420 MeV. We observe a tension of up to 3.5 standard
deviations between our lattice results for $\Delta\alpha_{\rm had}^{(5)}(-Q^2)$
and estimates based on the $\textit{R}$-ratio for space-like momenta in the
range $Q^2=3-7\,\rm GeV^2$. To obtain an estimate for
$\Delta\alpha_\mathrm{had}^{(5)}(M_Z^2)$, we employ the Euclidean split
technique. The implications for comparison with global electroweak fits are
assessed. |
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DOI: | 10.48550/arxiv.2212.02366 |