  We analyze some signatures of neutral Higgs bosons, produced in high energy
proton (anti)proton collisions, which decay primarily to top quarks. This
channel is clouded by a large irreducible $t\bar t$ background. We investigate
the $t\bar t$ invariant-mass distribution in the lepton+jets decay mode of
$t\bar t$ and a $t\bar t$ spin-spin correlation in the dilepton decay mode. At
the LHC such Higgs bosons can be detected in the $t\bar t$ invariant-mass
spectrum, and the spin-spin correlation studied by us is also sensitive to a
Higgs boson if this particle has a sizeable pseudoscalar component.
