Search for displaced leptons in the e-$\mu$ final state at the CMS experiment

A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at a center-of-mass energy of 13 TeV. Data used for the analysis were collected by the CMS detector during the 2015 run and correspond to an integrated luminosity of 2.6 inverse-femtobarns. Events are selected with an electron and muon that both have transverse impact parameter values between 0.02 cm and 10 cm. The search has been designed to be sensitive to a wide range of models with non-prompt e-mu final states. No significant excess is observed. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-mu final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to ctau = 2 cm, excluding masses below 870 GeV at 95% confidence level. In addition, the previous search for displaced leptons in the e-mu final state using proton-proton collisions produced by the LHC at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 inverse-femtobarns, and the work done during the Long-term Shutdown 1 (LS1) of the LHC to improve this search are included as well.