2023/08/10 by Jens Erler, Erler, Jens, Rodolfo Ferro-Hernández +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2308.05740
openalex publication_date 2023/08/10 · openalex created_date 2023/08/12 · openalex updated_date 2026/07/28
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 obtainΔα(5)(M2Z)=[279.5±0.9±0.59]×10-4 (Mainz Collaboration)Δα(5)(M2Z)=[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 αs, which is based on a rather conservative error. Using instead the PDG average, we find a total error on Δα(5)(M2Z) of 0.4×10-4. Furthermore, with a particular emphasis on the charm quark contributions, we also update Δα(5)(M2Z) when low-energy cross-section data is used as an input, obtaining Δα(5)(M2Z) = [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.