Optimization of the rejection of the ttbar background for the search of SuperSymmetry

This paper presented a method to reject the ttbar background apply to the Supersymmetric process where two gluino decay into 2 b quarks and the LSP (lightest supersymmetric particle). This rejection is done using a veto on the tau lepton. This report is going to show that even if this optimisation could in theory improve greatly the significance, the low efficiency of the tau identification is going to limit us to an augmentation of a few percent of the significance.This report also contain an analyse of the Atlas trigger.