Search for the associated production of a Higgs boson with a top quark pair in final states with a $\tau$ lepton at $\sqrt{s} = 13~\mathrm{TeV}$

Results of a search for the standard model Higgs boson produced in association with a top quark pair in final states with $\tau$ leptons are presented. The analyzed dataset corresponds to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$ which has been recorded in proton-proton collisions at $\sqrt{s} = 13~\mathrm{TeV}$ center-of-mass energy by the CMS experiment during LHC $\mathrm{Run}~2$. The sensitivity of the search is improved by using matrix element and machine learning methods to separate the signal from backgrounds. The measured signal rate amounts to $0.72^{+0.62}_{-0.53}$ times the production rate expected in the standard model, with an observed (expected) significance of $1.4\sigma$ ($1.8\sigma$). An upper limit on the signal rate of $2.0$ the standard model production rate is set at the $95\%$ confidence level.