TopFlav – Top-flavor couplings at the FCC-ee
Final Report Abstract
Present experiments in collider-based particle physics seek to discover physics beyond the Standard Model of Particle Physics (SM) in two ways. New particles are either being searched for directly or, in contrast, precision measurements are being compared with theoretical predictions. The latter approach involves the testing of specific models, such as those involving supersymmetry, exotic particles, or new forces. Alternatively, possible effects on experimentally accessible observables may be parameterized in terms of a (mostly) model-independent effective field theory (EFT). Apart from tensions in the flavor sector, no indication of physics beyond the SM has been found until today. Currently, a novel generation of experiments is being considered, with a focus on precision measurements involving electrons and positrons. The objective of the present project is to estimate the sensitivity of one such experiment, the FCC-ee, to the third-generation flavour sector based on measurements involving top quarks. The project has been divided into three distinct studies. In the first subproject, the sensitivity of a selection of top-quark observables with respect to EFT-operators was estimated, and for the most promising observables, the expected precision of these observables with an FCC-ee setup has been estimated. In the second subproject, these predictions were utilised to perform a global fit of a virtual set of measurements, thereby obtaining insights on the potential of the FCC-ee to constrain individual EFT operators. In the third subproject, a method to measure two electroweak precision observables involving bottom quarks with unprecedented precision was developed, and a full uncertainty budget was evaluated for a realistic FCC-ee setup. The results were prepared as input to the FCC Feasibility Study, which is to be concluded in 2025.
Publications
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Electroweak heavy flavour precision observables: connecting open dots with the FCC-ee, doctoral thesis, TU Dortmund University/University of Clermont-Auvergne, August 2024
L. Röhrig
