SEARCH FOR ELECTROWEAK PRODUCTION OF SUPERSYMMETRIC PARTICLES AT THE LHC RUN 2 WITH THE ATLAS DETECTOR

Two closely related searches for the electroweak production of Supersymmetric particles are presented in this manuscript. The analyses are based on the proton-proton collision data from the Large Hadron Collider Run 2, with a center-of-mass energy of 13 TeV, collected by the ATLAS experiment. Different Supersymmetric signal models are considered. The first search targets the pair production of either the Supersymmetric partners of the leptons (sleptons) or the $W$ boson and charged Higgs boson super-partners (charginos). In the latter case, the decay of charginos via sleptons is assumed. The search uses data collected by ATLAS between 2015 and 2016, with an integrated luminosity of 36.1 fb$^{-1}$. The second search targets the direct production of chargino pair with $W$ boson mediated decay. The analysis for the observation of the process was performed using the data collected by ATLAS between 2015 and 2017, reaching an integrated luminosity of 80.5 fb$^{-1}$. The signature, common to all the SUSY signal models considered, consists of two charged leptons (electrons or muons) and missing transverse energy. No significant fluctuation above the Standard Model prediction was observed in the analyses. New exclusion limits, tighter than the previously available results, were placed on the masses of the SUSY particles: slepton masses up to 500 GeV are excluded at 95%~CL. Chargino masses up to 700 GeV are excluded in the case of the decay mediated by a slepton, while considering the $W$ boson mediated decay the limit on the chargino mass is 410 GeV.