First-generation quark couplings

Dataset contains data and codes related to the study of the possible use of radiative processes for precise measurement of first-generation quark couplings at future electron-positron collider running at the Z-pole. Results of the study were summarized in the publication "Determination of the first-generation quark couplings at the Z-pole" published in J. High Energ. Phys. 11 (2025) 050.This research was part of the project "Realistic simulations of exotic processes at future e+e- colliders" funded by National Science Centre, Poland, under grant agreement nr 2021/43/B/ST2/01778.MethodologyThe study was based on large event samples of quark pair-production events for electron-positron collider running at the Z-pole. Samples were generated with the WHIZARD program and processed with the DELPHES framework to model detector performance. Event selection efficiencies and acceptance of the cut used to select events with final state radiation extracted from the Monte Carlo simulation were then used in the semi-analytical framework to extract quark pair-production cross sections and quark couplings. We present a method to extract the values of the Z couplings to light quarks based on up- and down-quarks’ different contributions to radiative and non-radiative Z boson decays. We show that systematic uncertainty in the heavy-flavour tagging performance is the key factor in the analysis, and that reducing it to the sub-permille level is crucial to fully profit from the high luminosity of future e+e− machines.Files:example Jupyter notebook (Python scripts) for studying coupling measurement precision as a function of the integrated collider luminosity, for different assumptions concerning systematic uncertainties in flavour tagging (Fig. 7 in the paper),input file with photon cut acceptance for radiative and non-radiative events, for different quark flavours (required by the Jupyter notebook)CSV files with final analysis results: expected uncertainties in the quark coupling extraction as a function of the analysis cut and collider luminosity, as presented in Figs. 4 and 7 of the paper.PDF and PNG files of the figuresSoftware tools usedWHIZARD Event Generator web page: https://whizard.hepforge.org/DELPHES: https://github.com/delphes/delphes