A bstract In a high-energy physics data analysis, the term “ fake ” backgrounds refers to events that would formally not satisfy the (signal) process selection criteria, but are accepted nonetheless due to mis-reconstructed particles. This can occur, e.g., when leptons from secondary decays are incorrectly identified as originating from the hard-scatter interaction point (known as non-prompt leptons ), or when other physics objects, such as hadronic jets, are mistakenly reconstructed as leptons