Search for a heavy vector boson decaying to two gluons in pp ̄ collisions at sqrt[s]=1.96 TeV

We present a search for a new heavy vector boson Z′ that decays to gluons. Decays to on-shell gluons are suppressed, leading to a dominant decay mode of Z′→g∗g. We study the case where the off-shell gluon g∗ converts to a pair of top quarks, leading to a final state of tt ̄g. In a sample of events with exactly one charged lepton, large missing transverse momentum and at least five jets, corresponding to an integrated luminosity of 8.7 fb−1 collected by the CDF II detector, we find the data to be consistent with the standard model. We set upper limits on the production cross section times branching ratio of this chromophilic Z′ at 95% confidence level from 300 to 40 fb for Z′ masses ranging from 400 to 1000 GeV/c2, respectively.