Dortmund 2021 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

T: Fachverband Teilchenphysik

T 8: Top quark production I

T 8.8: Vortrag

Montag, 15. März 2021, 17:45–18:00, Th

Measurement of the tZq cross section in events with two leptons — •Federica Cecilia Colombina — Windmühlenweg 27, 22607 Hamburg, Germany

In the years 2016-2018 the CMS Experiment at CERN's Large Hadron Collider (LHC) recorded a large amount of proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 inverse fb. In this work, events in which a single top quark is produced in association with a Z-boson are investigated. Particular focus is on final states in which two leptons originate from the Z boson and the top quark decays hadronically. The discrimination between signal and backgrounds is optimized by testing different methods for the event reconstruction in conjunction with a Deep Neural Network (DNN). It is shown that the use of jet kinematics that are associated with the particles in the final state improves the performance over cases where the event reconstruction information is not used. A statistical fit is then performed to the DNN output, reaching an expected signal significance for tZq events of 2.4 standard deviations. Further optimization of the analysis, e.g. by use of additional control regions, is being studied.