Precise measurement of light-quark electroweak couplings at future colliders

TL;DR

This paper discusses how future lepton colliders can precisely measure Z-boson couplings to light quarks, testing the Standard Model and probing for new physics through detailed analysis of radiative decays.

Contribution

It introduces a method to extract Z-quark couplings using radiative decay analysis at future colliders, with preliminary results for ILC.

Findings

Preliminary extraction of Z-quark couplings at ILC.

Method to distinguish photon sources in decay analysis.

Potential to detect deviations from Standard Model predictions.

Abstract

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 could reveal potential discrepancies between the fundamental theory and experimental data. Future lepton colliders offering high statistics of Z bosons would be an excellent tool to perform such a measurement based on comparison of radiative and non-radiative hadronic decays of the Z boson. Due to the difference in quark charge, the relative contribution of the events with final-state radiation (FSR) directly reflects the ratio of up- and down-type quark decays. Such an analysis requires a proper distinction between photons coming from different sources, including initial-state radiation (ISR), FSR, parton showers and hadronisation. In our talk, we will show how to extract the values of the Z couplings to quarks and present preliminary results of the analysis for ILC.