Study of top quark events in the search for physics beyond the Standard Model at the Large Hadron Collider with the CMS detector

Lepton Flavour Universality (LFU) is a global accidental symmetry of the Standard Model (SM). LFU predicts that all charged leptons must have the same couplings and their only difference must come from the different mass. Tests of this behaviour are of great interest as deviations from this prediction would be a clear signal of New Physics (NP).

In this work, a LFU measurement is performed studying the leptonic decays of W bosons in top quark events, including in the final state electrons, muons and taus. An orthogonal method, employing double ratio of different leptonic final states, is used to reduce the impact of systematic uncertainties and improve the precision.

Machine Learning techniques are employed in the separation of signal and background events exploiting the large amount of data collected in CMS at the LHC Run2