Slepton discovery in electroweak cascade decay

The LHC studies on the MSSM slepton sector have mostly been focused on direct slepton Drell-Yan pair production. In this paper, we analyze the case when the slep- tons are lighter than heavy neutralinos and can appear in the on-shell decay of neutralino states. In particular, we have studied the χ ± χ 0 associated production, with the consequent decays of χ ± → νllχ 0 and χ 0 → llχ 0 via on-shell sleptons. The invariant mass of the lep- ton pairs, mll, from the neutralino decay has a distinctive triangle shape with a sharp kinematic cutoff. We discuss the utilization of this triangle shape in mll distribution to identify the slepton signal. We studied the trilepton plus missing ET signal and obtained the effective cross section, σ × BR × acceptance, that is needed for a 5σ discovery as a function of the cutoff mass for the LHC with center of mass energy 14TeV and 100 fb −1 integrated luminosity. Our results are model independent such that they could be applied to other models with similar decay topology. When applied to the MSSM under simple assumptions, it is found that with 100 fb −1 integrated luminosity, a discovery reach in the left-handed slepton mass of about 600GeV could be reached, which extends far beyond the slepton mass reach in the usual Drell-Yan studies.