%0 Electronic Article
%A Mekala, Krzysztof
%A Jeans, Daniel
%A Reuter, Jürgen
%A Tian, Junping
%A Żarnecki, Aleksander Filip
%T Determination of the first-generation quark couplings at the Z-pole
%N DESY-25-063
%M PUBDB-2025-01355
%M DESY-25-063
%M arXiv:2504.11365
%D 2025
%Z 22 pages, 8 figures
%X Electroweak Precision Measurements are stringent tests of the Standard Model and sensitive probes to New Physics. Accurate studies of the Z-boson couplings to the first-generation quarks, which are currently constrained from LEP data to a few percent, could reveal potential discrepancies from the theory predictions. Future e<sup>+</sup>e<sup>−</sup> colliders running at the Z-pole would be an excellent tool for an analysis based on a comparison of radiative and non-radiative Z boson decays. In this paper, we present a method to extract the values of the Z couplings to light quarks and discuss the uncertainty of the measurement, including contributions from various systematic effects. We show that systematic uncertainty in the heavy-flavour tagging performance is the key factor in the analysis and reducing it to a sub-permille level might be crucial to fully profit from the high luminosity of future e<sup>+</sup>e<sup>−</sup> machines. The measurement could improve the LEP results by at least an order of magnitude.
%F PUB:(DE-HGF)25
%9 Preprint
%R 10.3204/PUBDB-2025-01355
%U https://bib-pubdb1.desy.de/record/626276