Final charged-lepton angular distribution and possible anomalous top-quark couplings in pp→tt¯X→ℓ+X′

Possible anomalous (or nonstandard) top-quark interactions with the gluon and those with the W boson induced by SU(3)×SU(2)×U(1) gauge-invariant dimension-6 effective operators are studied in pp→tt¯X→ℓ+X′ ( ℓ=e or μ ) at the Large Hadron Collider (LHC). The final charged-lepton ( ℓ+ ) angular distribution is first computed for nonvanishing nonstandard top-gluon and top- W couplings with a cut on its transverse momentum. The optimal-observable procedure is then applied to this distribution in order to estimate the expected statistical uncertainties in measurements of those couplings that contribute to this process in the leading order