Search for top squark pair production in a di-τ (semi-leptonic) final state at √s = 13 TeV with the CMS detector with the full Run 2 dataset

	Looking for beyond standard model (BSM) physics is a very high priority agenda at the LHC. Among the various BSMs, the supersymmetry (SUSY) based models, e.g the minimal super-symmetric standard model (MSSM), are the most competitive ones. In this study we analyze collision data to search for a signature of the top squark (or stop quark), the supersymmetric counter part of the top quark in a di-tau final state, targeting the high tanβ scenario of the MSSM. In our final state one tau decays hadronically and other tau decays leptonically (electron or muon). In this talk, I will present my study of top squark search in both “1τh+1 muon” and “1τh+1 electron” final state with 137 fb-1 of data collected in full Run2. The selection of signal events, main background condtributions, data-driven fake background estimation method, effect of different systematics and expected exclusion limit on the top squark mass will be discussed in the presentation.