Search for top squark pair production in a di-tau final state in proton-proton collisions at $ \sqrt{s} = 13~\mathrm{TeV} $

A search for the pair production of the supersymmetric partner of the top quark, the top squark, produced in proton-proton collision events at $ \sqrt{s} = 13~\mathrm{TeV} $ is presented in final states containing hadronically decaying tau leptons and large missing transverse momentum. These final states are highly sensitive to high $ \tan{\beta} $ 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~\mathrm{fb}^{-1} $ which was recorded by the CMS detector during 2016 and 2017. No significant excess is observed with respect to the background prediction, and exclusion limits at $ 95 \% $ confidence level are presented in the top squark and lightest neutralino mass plane within the framework of simplified models. It is found that top squark masses up to 1100 GeV are excluded for a nearly massless neutralino.