2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194509We 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.5 pages, 4 figures; version to appear in PRLHigh Energy Physics - PhenomenologyHigh Energy Physics - Experimenttext