We list all possible dimension-six CP-conserving SUcβ(3)ΓSULβ(2)ΓUYβ(1) invariant operators involving the third-family quarks which
could be generated by new physics at a higher scale. Expressions for these
operators after electroweak gauge symmetry breaking and the induced effective
couplings WtbΛ, XbbΛ and XttΛ(X=Z,Ξ³,g,H) are
presented. Analytic expressions for the tree level contributions of all these
operators to the observables Rbβ and AFBbβ at LEP I,
Ο(e+eββbbΛ) and AFBbβ at LEP II,
Ο(e+eββttΛ) and AFBtβ at the NLC, as well as
Ο(ppΛββtbΛ+X) at the Tevatron upgrade, are provided.
The effects of these operators on different electroweak observables are
discussed and numerical examples presented. Numerical analyses show that in the
coupling region allowed by Rbβ and AFBbβ at LEP I, some of the new
physics operators can still have significant contributions at LEP II, the
Tevatron and the NLC.Comment: 25 page