Özet:
The search for pair-produced heavy iso-singlet leptons predicted by Grand Unified Theory (GUT) based on group E6 is detailed in this study. The discovery channel through which the search has been conducted is pp→L_e L ‾_e→ZeWν_e→3l 2j E_T^miss. The data used in the study is the ATLAS Run 2 data which has an integrated luminosity of L=139 fb^(-1) from proton-proton collisions at 13 TeV center of mass-energy. A cut-based event selection has been performed to maximize signal to background yields. Exclusion limits without systematic uncertainties have been obtained, and the results have been found to be promising with the possibility to increase the lower mass limit of the heavy charged lepton to about 250 GeV from the previous limit of 100 GeV.