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Perturbative contributions to $$ \Delta {\alpha}^{(5)}\left({M}_Z^2\right)

Erler, Jens ; Ferro-Hernández, Rodolfo

The journal of high energy physics, 2023-12, Vol.2023 (12), Article 131 [Periódico revisado por pares]

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  • Título:
    Perturbative contributions to $$ \Delta {\alpha}^{(5)}\left({M}_Z^2\right)
  • Autor: Erler, Jens ; Ferro-Hernández, Rodolfo
  • É parte de: The journal of high energy physics, 2023-12, Vol.2023 (12), Article 131
  • Descrição: A bstract We compute a theoretically driven prediction for the hadronic contribution to the electromagnetic running coupling at the Z scale using lattice QCD and state-of-the-art perturbative QCD. We obtain {\displaystyle \begin{array}{cc}\Delta {\alpha}^{(5)}\left({M}_Z^2\right)=\left[279.5\pm 0.9\pm 0.59\right]\times {10}^{-4}& \left(\textrm{Mainz}\ \textrm{Collaboration}\right)\\ {}\Delta {\alpha}^{(5)}\left({M}_Z^2\right)=\left[278.42\pm 0.22\pm 0.59\right]\times {10}^{-4}& \left(\textrm{BMW}\ \textrm{Collaboration}\right),\end{array}} Δ α 5 M Z 2 = 279.5 ± 0.9 ± 0.59 × 10 − 4 Mainz Collaboration Δ α 5 M Z 2 = 278.42 ± 0.22 ± 0.59 × 10 − 4 BMW Collaboration , where the first error is the quoted lattice uncertainty. The second is due to perturbative QCD, and is dominated by the parametric uncertainty on {\hat{\alpha}}_s α ̂ s , which is based on a rather conservative error. Using instead the PDG average, we find a total error on \Delta {\alpha}^{(5)}\left({M}_Z^2\right) Δ α 5 M Z 2 of 0 . 4 × 10 − 4 . Furthermore, with a particular emphasis on the charm quark contributions, we also update \Delta {\alpha}^{(5)}\left({M}_Z^2\right) Δ α 5 M Z 2 when low-energy cross-section data is used as an input, obtaining \Delta {\alpha}^{(5)}\left({M}_Z^2\right) Δ α 5 M Z 2 = [276 . 29 ± 0 . 38 ± 0 . 62] × 10 − 4 . The difference between lattice QCD and cross-section-driven results reflects the known tension between both methods in the computation of the anomalous magnetic moment of the muon. Our results are expressed in a way that will allow straightforward modifications and an easy implementation in electroweak global fits.
  • Idioma: Inglês
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  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

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