Lepton distribution as a probe of new physics in production and decay of the<b><i>t</i></b>quark and its polarization

Abstract

We investigate the possibilities of studying new physics in various processes\nof t-quark production using kinematical distributions of the secondary lepton\ncoming from decay of t quarks. We show that the angular distributions of the\nsecondary lepton are insensitive to the anomalous tbW vertex and hence are pure\nprobes of new physics in a generic process of t-quark production. The energy\ndistribution of the lepton is distinctly affected by anomalous tbW couplings\nand can be used to analyze them independent of the production process of t\nquarks. The effects of t polarization on the distributions of the decay lepton\nare demonstrated for top-pair production process at a gamma-gamma collider\nmediated by a heavy Higgs boson.\n