A search for supersymmetry at 13 TeV with two same-sign leptons or three leptons at the ATLAS detector. Latest analysis results and statistical interpretations

Supersymmetry (SUSY) is one of the most studied theories to extend the Standard Model. In R-Parity conserving (RPC) models, the lightest supersymmetric particle (LSP), which is typically the lightest neutralino χ⁰₁, is stable. In scenarios which allow a violation of the R-Parity (RPV), no stable SUSY paricles are produced. In this talk a search for supersymmetry in final states with two leptons of the same electric charge or three leptons, jets and E_T^miss is presented. While the same-sign signature is present in many SUSY scenarios, Standard Model processes leading to such events have very small cross-sections. Therefore, this analysis benefits from a small background in the signal regions leading to a good sensitivity especially in SUSY scenarios with compressed mass spectra. This search was performed with the data recorded with the ATLAS detector during the years 2015 and 2016 corresponding to a total integrated luminosity of 13.2 fb^-1. The sensitivity to a big variety of supersymmetric models is illustrated by the interpretation of the results in the context of several SUSY benchmark scenarios. No significant excess above the Standard Model prediction is observed. The results can be used to set model-independent limits to new physics signals as well as deriving limits on the masses of the superpartners in different SUSY scenarios.