  We discuss the sensitivity of a 100 TeV pp collider to heavy particles
decaying to top-antitop final states. This center-of-mass energy, together with
an integrated luminosity of 10 ab-1, can produce heavy particles in the mass
range of several tens of teraelectronvolts (TeV). A Monte Carlo study has been
performed using boosted-top techniques to reduce QCD background for the
reconstruction of heavy particles with masses in the range of 8-20 TeV, and
various widths. In particular, we have studied two models that predict heavy
states, a model with an extra gauge boson (Zprime) and with a Kaluza-Klein (KK)
excitation of the gluon (gKK). We estimate the sensitive values of $\sigma
\times$Br of about 2 (4) fb for Zprime (gKK), with a corresponding mass reach
of 13 (20) TeV.
