A New Decoupling Theorem in Top-Quark Physics
  Angular distribution of a secondary particle in top-quark production/decay is studied in a simple and general manner. It is shown that the distribution does not depend on any possible anomalous top-quark-decay interactions whatever the production mechanism is when certain well-justified conditions are satisfied. Some analyses using the final- state lepton are presented as an example of its application. 
Zenro Hioki (Univ. Tokushima, Japan)