Search for $\mathrm{t\bar{t}}$ resonances in boosted semileptonic final states in pp collisions at $\sqrt{s}=13~\mathrm{TeV}$

We present a search for the production of heavy resonances decaying into top-antitop quark pairs. The analysis is performed in the lepton+jets channel using $2.6~\mathrm{fb}^{-1}$ of data collected in proton-proton collisions at ${\sqrt{s}=13}~\mathrm{TeV}$ with the CMS detector. The selection is optimized for heavy resonance masses, where the top quarks have large Lorentz-boosts. This results in non-isolated leptons from the $\mathrm{W} \to \ell \nu$ decay and two or more quarks reconstructed in a single jet from the $\mathrm{t} \to \mathrm{bW} \to \mathrm{bqq'}$ decay. These jets are identified using top-tagging algorithms. No evidence for resonant $\mathrm{t\bar{t}}$ production is found and upper limits on the production cross section of heavy resonances are set.