Constraining the top quark Yukawa coupling from $\text{t}\bar{\text{t}}$ differential cross sections in the lepton+jets final state in proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$

A measurement of the top quark Yukawa coupling from the top quark-antiquark ($\text{t}\bar{\text{t}}$) differential production cross sections in proton-proton collisions with the lepton+jets channel is presented. Corrections due to electroweak bosons exchange, including the Higgs boson, between the final state top quarks can produce large distortions of differential distributions near the energy threshold of top quark pair production. Therefore precise measurements of these distributions are sensitive to the Yukawa coupling. This analysis is based on data collected by the CMS experiment at the LHC at $\sqrt{s}=13~\mathrm{TeV}$ corresponding to an integrated luminosity of $35.8~\mathrm{fb}^{-1}$. Top quark events are reconstructed with at least three jets in the final state. A novel technique is introduced to reconstruct the $\text{t}\bar{\text{t}}$ system for events with one missing jet. This technique enhances the experimental sensitivity in the low invariant mass region, $M_{\text{t}\bar{\text{t}}}$. The data yields in $M_{\text{t}\bar{\text{t}}}$, the rapidity difference $|y_\text{t}-y_{\bar{\text{t}}}|$, and the number of reconstructed jets are compared with distributions representing different Yukawa couplings. These comparisons are used to extract an upper limit on the top quark Yukawa coupling of 1.67 (1.62 expected) at $95\%$ confidence level.