TOP-QUARK INTERACTIONS AND THE SEARCH FOR NEW PHYSICS

A complete characterization of all the possible effective interactions up to dimension five of the: top and bottom quarks with the electrowe ak gauge bosons have been made within the context of the nonlinear chi ral Lagrangian. The dimension-five operators (19 in total) can contrib ute to the VLVL --> <t(t)over bar> or <t(b)over bar> amplitudes with a leading energy power of E-3 (E-2) for fermion pairs with same (opposi te) sign helicities. Because of the equivalence between the longitudin al weak boson and the corresponding would-be Goldstone boson in high e nergy collisions (Goldstone equivalence theorem), they are sensitive t o the electroweak symmetry-breaking sector. We also show the top quark production rates at the CERN LHC and the LC via VLVL fusion processes . At the LC, if no anomalous production rate is found, these coefficie nts can be bound (based on the naive dimensional analysis) to be of or der 10(-1). This is about an order of magnitude mon stringent than the bounds for the next-to-leading-order bosonic operators commonly studi ed in VLVL --> VLVL scatterings. The effects on a CP-odd observable ar e also briefly discussed.