Final charged-lepton angular distribution and possible anomalous   top-quark couplings in p p -> t tbar X -> l^+ X'
  Possible anomalous (or nonstandard) top-quark interactions with the gluon and those with the W boson induced by SU(3) x SU(2) x U(1) gauge-invariant dimension-6 effective operators are studied in p p -> t tbar X -> l^+ X' (l=e or mu) 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. 
Zenro Hioki (U. Tokushima) and Kazumasa Ohkuma (Okayama U. Science)
hep-ph hep-ex