Search for associated production of a Higgs boson and a single top quark in proton-proton collisions at √s = 13 TeV

Abstract

A search is presented for the production of a Higgs boson in association with a single top quark, based on data collected in 2016 by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of 35.9 fb−1. The production cross section for this process is highly sensitive to the absolute values of the top quark Yukawa coupling, yt; the Higgs boson coupling to vector bosons, gHVV; and, uniquely, their relative sign. Analyses using multilepton signatures, targeting H → WW, H → ττ, and H → ZZ decay modes, and signatures with a single lepton and a b¯b pair, targeting the H → b¯b decay, are combined with a reinterpretation of a measurement in the H → γγ channel to constrain yt. For a standard model–like value of gHVV, the data favor positive values of yt and exclude values of yt below about −0.9yt^SM.