Speaker
Description
The first dedicated LHC search for pair production of vector-like electrons and muons is presented. The analysis is based on a dataset of proton-proton collisions at sqrt(s)=13 TeV recorded with the ATLAS detector during Run 2 of the LHC, corresponding to an integrated luminosity of 140 fb-1. Events are categorised into channels based on the multiplicity of light charged leptons (electrons or muons), consisting of two, three, or four or more light leptons. Deep neural networks are used in each channel to further categorise events into signal regions targeting distinct signal topologies (e.g. llHH, llHV, llVV, etc), while discriminating against standard model backgrounds. Dedicated control regions are defined to constrain major standard model backgrounds (ttbar, ttZ, diboson, and ttW) and used in a simultaneous fit with signal regions to data. The results are interpreted as upper limits on the pair-production cross section as a function of vector-like lepton mass, separately for SU(2) doublet and singlet representations.
