  We study the sensitivity of top pair production with six-fermion decay at the
LHC to the presence and nature of an underlying Z' boson, accounting for full
tree-level Standard Model ttbar interference, with all intermediate particles
allowed off-shell. We concentrate on the lepton-plus-jets final state and
simulate experimental conditions, including kinematic requirements and top
quark pair reconstruction in the presence of missing transverse energy and
combinatorial ambiguity in jet-top assignment. We focus on the differential
mass spectra of the cross section and asymmetry observables, especially
demonstrating the use of the latter in probing the coupling structure of a new
neutral resonance, in addition to cases in which the asymmetry forms a
complementary discovery observable.
