TY  - EJOUR
AU  - Mekala, Krzysztof
AU  - Jeans, Daniel
AU  - Reuter, Jürgen
AU  - Tian, Junping
AU  - Żarnecki, Aleksander Filip
TI  - Determination of the first-generation quark couplings at the Z-pole
IS  - DESY-25-063
M1  - PUBDB-2025-01355
M1  - DESY-25-063
M1  - arXiv:2504.11365
PY  - 2025
N1  - 22 pages, 8 figures
AB  - 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.
LB  - PUB:(DE-HGF)25
DO  - DOI:10.3204/PUBDB-2025-01355
UR  - https://bib-pubdb1.desy.de/record/626276
ER  -