Measurement of jet substructure observables in $\mathrm{t}\bar{\mathrm{t}}$ events from proton-proton collisions at $\sqrt{s}=$ 13TeV

A measurement of jet substructure observables is presented using $\mathrm{t}\bar{\mathrm{t}}$ events in the lepton+jets channel from proton-proton collisions at $\sqrt{s}=$ 13 TeV recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb${}^{-1}$. Multiple jet substructure observables are measured for jets identified as bottom, light-quark, and gluon jets, as well as for inclusive jets (no flavor information). The results are unfolded to the particle level and compared to next-to-leading-order predictions from POWHEG interfaced with the parton shower generators PYTHIA 8 and HERWIG 7, as well as from SHERPA 2 and DIRE 2. A value of the strong coupling at the Z boson mass, ${\alpha }_S(m_{\mathrm{Z}})=$ 0.115 ${}_{-0.013}^{+0.015}$, is extracted from the substructure data at leading-order plus leading-log accuracy.