Search for $\it tZq$ in dilepton final states with Machine Learning techniques

Abstract

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 analysis uses data collected with the Compact Muon Solenoid (CMS) detector between 2016 and 2018, corresponding to an integrated luminosity of 137 fb$^-$$^1$; data are produced from proton-proton collisions at the Large Hadron Collider (LHC), with a center of mass energy equal to 13 TeV. The discrimination between signal and backgrounds is optimized by testing different methods for the event reconstruction and with the implementation of a Deep Neural Network (DNN). In the last part of the analysis, a statistical fit is performed to the DNN output for the signal extraction, reaching an expected significance of the $\it tZq$ signal overbackground of 2.4o