DIMENSION-6 CP-CONSERVING OPERATORS OF THE 3RD-FAMILY QUARKS AND THEIR EFFECTS ON COLLIDER OBSERVABLES

We list all possible dimension-six CP-conserving SUc(3)xSU(L)(2)xU(Y)( 1)-invariant operators involving the third-family quarks which could b e generated by new physics at a higher scale. Expressions for these op erators after electroweak gauge symmetry breaking and the induced effe ctive couplings Wt(b) over bar, Xb(b) over bar, and Xt(t) over bar (X = Z, gamma,g, H) are presented. Analytic expressions for the tree leve l contributions of all these operators to the observables R-b and A(FB )(b) at CERN LEP I, sigma(e(+)e(-) --> <b(b)over bar>) and A(FB)(b) at LEP II, sigma(e(+)e(-) --> <t(t)over bar>) and A(FB)(t) at the Next L inear Collider (NLC). as well as sigma(<p(p)over bar> --> <t(b)over ba r> + X) at the Fermilab Tevatron upgrade, are provided. The effects of these operators on different electroweak observables are discussed an d numerical examples presented. Numerical analyses show that in the co upling region allowed by R-b and A(FB)(b) at LEP I, some of the new ph ysics operators can still have significant contributions at LEP II, th e Tevatron, and the NLC.