Measurement of differential cross sections for top quark pair production and associated jets using the lepton+jets final state in proton-proton collisions at $13\,\mathrm{TeV}$

Differential and double-differential cross sections for the production of top quark pairs in proton-proton collisions at $13\,\mathrm{TeV}$ are measured as a function of kinematic variables of the top quarks and the top quark-antiquark system. In addition, kinematic properties and multiplicities of jets associated with the production of top quark pairs are measured. This analysis is based on data collected by the CMS experiment at the LHC in 2016 corresponding to an integrated luminosity of $35.8\,\mathrm{fb}^{-1}$. The measurements are performed in the lepton+jets decay channels with a single muon or electron and jets in the final state. The differential cross sections are presented at particle level, within a phase space close to the experimental acceptance, and at parton level in the full phase space. The results are compared to several standard model predictions that use different methods and approximations for their calculations. The kinematic properties of the top quarks and the top quark-antiquark system are well described apart from a softer transverse momentum of the top quarks, which has already been observed in previous measurements. The kinematic distributions and multiplicities of jets can be modeled by certain combinations of next-to-leading order calculations and parton shower models.