Top squark pair production search in tau nal states in CMS experiment, and calorimetric tau reconstruction.

	I will present a search for the pair production of the supersymmetric partner of the top quark, the top squark, produced in proton-proton collision events at  √s = 13 TeV in final states containing hadronically decaying tau leptons and large missing transverse momentum.  These final states are highly sensitive to high tan β or higgsino-like scenarios in which decays of electroweak gauginos to tau leptons are dominant. The search uses a dataset corresponding to an integrated luminosity of 77     fb-1 which was recorded by the CMS detector during 2016 and 2017. In the second half of my talk I will introduce a calorimeter-based tau (calo-tau) reconstruction technique that is better suited than the standard Hadrons-Plus-Strips (HPS) algorithm for reconstructing highly energetic taus. I will discuss the details of the calo-tau algorithm and its performance compared to HPS.