Search for a vectorlike top partner produced through electroweak interaction and decaying to a top quark and a Higgs boson using boosted topologies in the all-hadronic final state

A search is performed for the electroweak production of a vectorlike top quark partner T of charge $+2/3$ in association with a standard model top or bottom quark, using $2.3~{\rm fb^{-1}}$ of proton-proton collision data at $\sqrt{s}= 13~{\rm TeV}$ collected by the CMS experiment. The search targets T quarks decaying to a top quark and a Higgs boson in a fully hadronic final state. For a T quark with mass above $1~{\rm TeV}$, the daughter top quark and the Higgs boson are highly Lorentz-boosted and each can be reconstructed as a single hadronic jet. Jet substructure and b tagging techniques are used to identify the top quark and Higgs boson jets, and to suppress the standard model backgrounds, which are found to be consistent with observations. Upper limits at 95\%~CL are set on the product of the single T quark production cross section and the $\mathcal{B}(\rm{T}\rightarrow \rm{tH})$ that vary between $0.31-0.93$~pb for T quark masses in the range $1000-1800~{\rm GeV}$.