Search for the tH(H$\to \text{b}\bar{\text{b}}$) process in pp collisions at $\sqrt{s}=13\,\mathrm{TeV}$ and study of Higgs boson couplings

A search for the production of a Higgs boson in association with a single top quark (tH) is presented. The analysis focuses on Higgs boson decays to bottom quark-antiquark pairs and leptonic top quark decays. The full data set of pp collisions recorded by the CMS detector in 2016 at a center-of-mass energy of $13\,\mathrm{TeV}$, corresponding to an integrated luminosity of $35.9\,\mathrm{fb}^{-1}$, is analyzed. A multivariate classifier is used to discriminate signal candidates from the overwhelming background processes. Several scenarios for varied strength of the coupling of the Higgs boson to top quarks and to vector bosons are examined and limits on the combined cross section for Higgs boson production, either in association with a pair of top quarks or a single top quark, are derived. In addition, limits on the signal strength of Higgs boson production in association with a single top quark are set for two specific cases. The observed (expected) limit for tH production in the standard model is 89.5 ($41.4$) times the predicted cross section. In case of an inverted top-Higgs coupling, the observed (expected) limit is 5.83 ($2.94$) times the prediction.