Implementation of the ATLAS-SUSY-2018-04 analysis in the MadAnalysis 5 framework (staus in the di-tau plus missing transverse energy channel; 139 fb$^{−1}$)

We present the MadAnalysis 5 implementation and validation of the ATLAS-SUSY-2018-04 search. This ATLAS analysis targets direct stau production in events with two hadronic tau leptons, and probes 139 fb−1 of LHC proton–proton collisions at a center-of-mass energy of 13 TeV. The validation of our re-implementation relies on a comparison of our cutflow predictions with the auxiliary material and official results provided by the ATLAS collaboration in the context of two supersymmetry-inspired simplified benchmark models in which the Standard Model is extended by a neutralino and a stau decaying into a tau lepton and a neutralino. A first scenario focuses on very light staus, whereas a second one addresses heavier staus. Our predictions have been found to agree with ATLAS official cutflows at the level of 6–8% in the heavy stau scenario, and exhibit a larger discrepancy (of 15–50%) in the light stau scenario. This disagreement is however considered as not too significant, as both ATLAS and MadAnalysis 5 predictions come with large Monte Carlo numerical uncertainties.