Furong Yan will present his thesis topic, “Search for Physics Beyond the Standard Model in Top Quark Production with Additional Leptons in the Context of Effective Field Theory” in person.

Abstract: The dissertation presents a search for new physics impacting top quark productions within the framework of effective field theory (EFT). Potential new physics effects are parameterized in terms of 26 dimension-six EFT operators into the event yields of six distinct top production processes in the detector level. The analysis targets multilepton final states consisting of two leptons of the same charge, three leptons and four leptons. The events are further categorized and binned in terms of kinematic distributions in order to gain sensitivity to the new physics effects. A likelihood function is formulated based on the predicted distribution in each category, which is parameterized by 26 EFT parameters. The likelihood function is then fitted to the data obtained from 138 \fb of proton-proton collisions at a center of mass energy of 13 TeV collected by the CMS experiment from 2016 to 2018. Results are presented as the confidence intervals on the EFT parameters extracted from the likelihood fit. No significant deviation from the standard model (SM) prediction is observed.