  A search is presented for massive spin-1 Z' resonances decaying to a top
quark and a heavy vector-like top quark partner T. The search is based on a 2.6
inverse femtobarns sample of proton-proton collisions at 13 TeV collected with
the CMS detector at the LHC. The analysis is optimized for final states in
which the T quark decays to a W boson and a bottom quark. The focus is on
all-jet final states in which both the W boson and the top quark decay into
quarks that evolve into jets. The decay products of the top quark and of the W
boson are assumed to be highly Lorentz-boosted and cannot be reconstructed as
separate jets, but are instead reconstructed as merged, wide jets. Techniques
for the identification of jet substructure and jet flavour are used to
distinguish signal from background events. Several models for Z' bosons
decaying to T quarks are excluded at 95% confidence level, with upper limits on
the cross section ranging from 0.13 to 10 pb, depending on the chosen
hypotheses. This is the first search for a neutral spin-1 heavy resonance
decaying to a top quark and a vector-like T quark in the all-hadronic final
state.
