Data-driven methods for misreconstructed objects estimation in lepton final states using $pp$ collisions at $\sqrt{s}$=13 TeV with the ATLAS detector at the LHC

Neutrinos mass generation is needed to explain neutrino oscillations. Seesaw mechanisms offer a solution and motivate searches for heavy neutral leptons in either opposite-sign or same-sign leptons final states. This contribution discusses the challenging backgrounds for same-sign final states, either due to incorrectly identified jets as leptons or to mismesureaments of the electron charge.