Search for single production of vector-like quarks decaying to a b quark and a Higgs boson

A search is presented for single production of heavy vector-like quarks (B) that decay to a Higgs boson and a b quark, with the Higgs boson decaying to a highly boosted bb pair reconstructed as a single collimated jet. The analysis is based on data collected by the CMS experiment in proton-proton collisions at 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The data is consistent with background expectations, and upper limits are set at 95\% confidence level on the product of the B quark cross section and the branching fraction are obtained in the range 1.28--0.07 pb, for a narrow B quark with masses between 700 and 1800 GeV. The production of B quarks with widths of 10, 20 and 30\% of the resonance mass has also been considered for the first time, and the sensitivities obtained are similar to those obtained in the narrow width case. This is the first search for the single production of a B quark through its fully hadronic decay channel at the CERN LHC and the first study considering finite resonance widths of the B quark.