Search for Weakly-produced Supersymmetry in the Same-sign Di-lepton Final State at $\sqrt{s}=8$ TeV with the Atlas Detector

A search for weakly-produced $\tilde{\chi}^{\pm}_1$, $\tilde{\chi}^0_2$ supersymmetric particles decaying to two final state electrons or muons with the same electric charge is presented. The analysis is performed on 20.3 fb$^{-1}$ of integrated luminosity collected in 2012 with the Atlas Detector at the Large Hadron Collider, running at $\sqrt{s} = 8$ TeV. Pairs of like-sign leptons are collected and discriminated against background using Boosted Decision Trees trained on compressed supersymmetric simplified models. No significant excesses above background expectations are observed. The 95% confidence limits are placed on $\tilde{\chi}^{\pm}_1$, $\tilde{\chi}^0_2$ pairs decaying via W and Z bosons and via intermediate sleptons with two different assumptions on the relative slepton mass. In the most optimistic scenarios considered, $\tilde{\chi}^{\pm}_1$ below 410 GeV are excluded assuming a massless $\tilde{\chi}^0_1$. In the compressed scenario, $\tilde{\chi}^{\pm}_1$ $< 180$ GeV are excluded, with $\Delta$m $\tilde{\chi}^{\pm}_1$,$\tilde{\chi}^0_1$ $>20$ GeV. Results from this analysis are also combined with those from a complementary search in the three lepton final state.