PROBING ANOMALOUS TOP-QUARK COUPLINGS AT E-GAMMA-COLLIDERS - ART-NO 094004

We study in the effective Lagrangian approach the possibility of probi ng anomalous top quark charged current couplings in single top quark p roduction at a high-energy e gamma collider. We analyze all possible d imension-six CP-conserving operators which can give rise to an anomalo us Wtb coupling which represents new physics effects generated at a hi gher-energy scale. For those operators which also give rise to anomalo us Zb(b)over-bar or right-handed Wtb couplings, we find that they are strongly constrained by the existing R-b and b --> s gamma data. As a result, a collider with a luminosity of the order of 100 fb(-1) is req uired to observe anomalous effects. For other operators which currentl y are: subject to no strong constraints, the high-energy e gamma colli der can probe their couplings effectively because of the clean environ ment of such a collider. [S0556-2821(98)01719-6]