Measurement of differential $\mathrm{t}\bar{\mathrm{t}}$ production cross sections in the full kinematic range using lepton+jets events from pp collisions at $\sqrt{s}=13~\mathrm{TeV}$

Measurements of differential and double-differential cross sections of the production of top quark pairs ($\mathrm{t}\bar{\mathrm{t}}$) are presented in the lepton+jets channel with a single electron or muon and jets in the final state. The analysis combines signatures of top quarks with low transverse momentum $p_\mathrm{T}$, where the top decay products can be identified as separated jets and isolated leptons, and with high $p_\mathrm{T}$, where the decay products are collimated and overlap. The measurements are based on data collected by the CMS experiment at the LHC between 2016 and 2018, corresponding to an integrated luminosity of $137~\mathrm{fb}^{-1}$. The cross sections are presented at the parton and particle level, where the latter minimizes extrapolations based on theoretical assumptions. Both results are compared to standard model calculations using different combinations of next-to-leading order quantum chromodynamics (QCD) matrix elements and parton shower models. Most of the measured differential cross sections are well described by the predictions with the exception of some double-differential distributions. A calculation at next-to-next-to-leading order accuracy in QCD provides an improved description of the parton-level measurements. The inclusive $\mathrm{t}\bar{\mathrm{t}}$ cross section $\sigma_\mathrm{tot} = 791\pm 25~\mathrm{pb}$ is measured, which constitutes the most precise measurement in the lepton+jets channel to date.