Probing Anomalous Top-Couplings through the Final Lepton Angular and Energy Distributions at Polarized NLC

Abstract

The angular and energy distributions of the final lepton in e ebar t tbar --> l^{+-} X at next linear colliders (NLC) are analyzed a model-independent way for arbitrary longitudinal beam polarizations as sensitive tests of possible anomalous top-quark couplings. The angular-energy distribution is expressed as a combination of independent functions of the angle and the energy, where each anomalous parameter is the coefficient of an individual term. Every parameter could be thereby determined simultaneously via the optimal-observable procedure. On the other hand, anomalous tbW couplings totally decouple from the angular distribution, which enables us to study t-tbar-gamma/Z couplings exclusively.