Search for direct top squark pair production in final states with two leptons in $\sqrt{s} = 13$ TeV pp collisions using 3.2 fb$^{-1}$ of ATLAS data.

The results of a search for the direct pair production of supersymmetric partners of the top quark are reported using 3.2fb$^{-1}$ of integrated luminosity from LHC $pp$ collisions at $\sqrt{s}=13$ TeV collected by the ATLAS detector. Top squarks are searched for in events with two leptons (electrons or muons) in the final state. No excess above the Standard Model expectation is observed. Exclusion limits at 95% confidence level are derived on the mass of the top squark assuming that it decays with 100% branching ratio as $\tilde{t}_1 \rightarrow \tilde{\chi}^{\pm}_1 b \rightarrow \tilde{\chi}^{0}_1 W b$, for two different assumptions on the chargino $\tilde{\chi}^{\pm}_1$ and the lightest neutralino \$ \tilde{\chi}^{0}_1$ masses. These results extend the region of supersymmetric parameter space excluded by previous LHC searches.