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

A measurement of jet substructure observables is presented using tt events in the lepton + jets channel from proton-proton collisions at √s = 13  TeV recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9  fb^(01). 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, α_S(m_Z) = 0.115^(+0.015)_(−0.013), is extracted from the substructure data at leading-order plus leading-log accuracy.