(YSF) Search for top squarks and dark matter particles in opposite-charge dilepton final states at CMS

A search for new physics is presented in final states with two oppositely charged leptons, jets identified as originating from b quarks, and missing transverse momentum using 35.9/fb of CMS data recorded in 2016. Hypothetical signal events are efficiently separated from the dominant top quark pair background with requirements on missing transverse momentum and transverse mass variables, the latter reducing the background by four orders of magnitude. No significant deviation is observed from the expected background. The results are interpreted in terms of simplified models of pair produced scalar partners of top quarks (top squarks), as predicted by supersymmetric models. Exclusion limits reach up to top squark masses of 1.3 TeV for specific model assumptions. Additionally, pair production of dark matter particles via scalar or pseudoscalar mediators is tested, and the analysis provides exclusions of scalar mediators with masses below 100 GeV.