Dortmund 2021 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 52: Top quark decay and top properties II

T 52.5: Vortrag

Mittwoch, 17. März 2021, 17:00–17:15, Tb

Search for flavour-changing photon interactions in top-quark production and decay at √s = 13 TeV with the ATLAS experiment — Tomas Dado, Johannes Erdmann, •Benedikt Gocke, Florian Mausolf, and Olaf Nackenhorst — TU Dortmund, Lehrstuhl für Experimentelle Physik IV

In the Standard Model of particle physics, flavour-changing neutral currents (FCNC) are forbidden at tree level and are highly suppressed by the GIM mechanism at higher orders of perturbation theory. However, several extensions of the Standard Model predict larger branching ratios for FCNC processes.
One possible process with an FCNC includes a top quark that interacts with an up-type quark and a photon (tqγ coupling with q=u,c). A distinction is made between the production mode, in which a single top quark is produced via an FCNC interaction, and the decay mode, in which one of the top quarks of a tt system decays through an FCNC interaction.
Improvements of an ATLAS search that focused on the production mode with a partial Run-2 dataset (Phys. Lett. B 800 (2019) 135082) are shown. These include in particular, that decay and production mode are considered in the optimisation of the analysis, the full Run-2 data is used, and the background estimations are revisited.