Search for supersymmetry with two and three leptons and missing transverse momentum in the final state at \sqrt{s}=13 TeV with the ATLAS detector

This note reports on the searches for direct production of opposite-sign pair of the lightest charginos ($\tilde{\chi_{1}^{+}}\tilde{\chi_{1}^{-}}$) and the pair production of the lightest chargino with the next-to-the-lightest neutralino ($\tilde{\chi_{1}^{\pm}}\tilde{\chi_{2}^{0}}$) using 13.3 fb$^{-1}$ of integrated luminosity from LHC $pp$ collisions at $\sqrt{s}=13$ TeV collected by the ATLAS detector. These studies have been performed in final states including two and three leptons (electrons or muons) and large missing transverse momentum. The results have been found to be in agreement with the Standard Model expectations. Exclusion limits at 95% confidence level are derived on the masses of the $\tilde{\chi_{1}^{\pm}}/\tilde{\chi_{2}^{0}}$ (assumed to be mass degenerate) and the lightest neutralino ($\tilde{\chi_{1}^{0}}$) assuming 100% branching ratio of the $\tilde{\chi_{1}^{\pm}}$ and $\tilde{\chi_{2}^{0}}$ to sleptons ($\tilde{\ell}$). These results extend the region of supersymmetric parameter space excluded by the Run I LHC searches. For the case of $\tilde{\chi_{1}^{+}}\tilde{\chi_{1}^{-}}$ scenario the observed limit on the $m_{\tilde{\chi_{1}^{\pm}}}$ is at 620 GeV while for the case of $\tilde{\chi_{1}^{\pm}}\tilde{\chi_{2}^{0}}$ the observed limit on $m_{\tilde{\chi_{1}^{\pm}}/\tilde{\chi_{2}^{0}}}$ has been extended to 1 TeV for massless $\tilde{\chi_{1}^{0}}$.