A search for resonant ttbar production in all final states in pp collisions at sqrt(s) = 8 TeV

A search is presented for the production of heavy resonances decaying into top-antitop quark pairs in events with three different final states, defined by the number of leptons from the $\rm{t}\bar{\rm{t}} \to \rm{W}\rm{b}\rm{W}\rm{b}$ decay. The data correspond to an integrated luminosity of $19.7$~fb$^{-1}$ and was collected by the CMS detector in proton-proton collisions at $\sqrt{s}=8$~TeV. The selections are optimized for reconstruction of top quarks with high Lorentz boosts, where jet substructure techniques are used to enhance the sensitivity. No significant excess of events over the expected yield from standard model processes is observed. Upper limits on the production cross section of heavy resonances decaying to $\rm{t}\bar{\rm{t}}$ are calculated using all channels. A narrow leptophobic topcolor $\rm{Z}^\prime$ resonance with a mass below $2.4$~TeV is excluded at a 95\% confidence level. Limits are also derived for a broad $\rm{Z}^\prime$ resonance with 10\% width and a Kaluza-Klein excitation of the gluon in the Randall-Sundrum model.