Background studies for long-lived particles searches in the ATLAS muon spectrometer

In the search for long-lived particles decaying in the muon spectrometer, a single vertex method is preferred in order to increase sensitivity to longer lifetimes. Unfortunately, the ABCD method used to calculate the background associated with single-vertex events did not work properly using the preferred variables of vertex isolation and associated number of hits. This paper outlines the my efforts over the course of this summer to find the cause of the dysfunction of this ABCD plane, as well as the improvements I made.