New hints for testing anomalous top-quark interactions at future linear colliders

Angular and energy distributions for leptons and bottom quarks in the process e(+)e(-) --> (t) over bar t --> l(+/-)/ b((-)) ... have been calculated the most general top-quark couplings. The double distributions depend both on modification of the t (t) over bar production and t((-)) -->((-)) b W decay vertices. However, the leptonic angular distribution turned out to be totally insensitive to non-standard parts of Wtb vertex. Distributions of decay products for polarized top quark in its rest frame have been also calculated. It has been found that the factorization of energy and angular dependence for the double leptonic distribution noticed earlier for the Standard Model survives even if one allows for deviations from the V-A interactions, and the SM angular leptonic distribution turned out to be preserved by anomalous decay vertex. (C) 2000 Published by Elsevier Science B.V. All rights reserved.