Abstract:
Despite of the discovery of a Higgs-like particle in 2012, there are still many unanswered questions. Studying events with the same-sign dilepton and multilepton (SSML) may help to gain insight into those questions. In this presentation, I will give an overview of physics and challenges related to the analyses of SSML events, focusing on the three analyses I worked on, namely, search for beyond standard model physics, studies of ttH and ttW production and search for four-top production with the ATLAS detector.