  We study momentum distributions of the final-state charged lepton in ppbar/pp
--> ttbar --> l^+ X (l=e or mu) at hadron colliders, i.e., Tevatron and Large
Hadron Collider (LHC) in order to explore possible new-physics effects in the
top-quark sector. Assuming general model-independent ttbar g + ttbar gg and tbW
interactions beyond the standard model, we first derive analytical formulas for
the corresponding parton-parton processes. We then compute the lepton angular,
energy and transverse-momentum distributions in ppbar/pp collisions to clarify
how they are affected by those anomalous couplings.
