  We study top quark pair production to probe new physics at the LHC. We
propose reconstruction methods for $t\bar{t}$ semileptonic events and use them
to reconstruct the $t\bar{t}$ invariant mass. The angular distribution of top
quarks in their c.m. frame can determine the spin and production subprocess for
each new physics resonance. Forward-backward asymmetry and CP-odd variables can
be constructed to further delineate the nature of new physics. We parametrize
the new resonances with a few generic parameters and show high invariant mass
top pair production may provide an early indicator for new physics beyond the
Standard Model.
