  Using an effective Lagrangian approach, we perform a model-independent
analysis of the interactions among electroweak gauge bosons and the third
generation quarks, i.e. the Wtb, Ztt and Zbb couplings. After one imposes the
known experimental constraint on the Z b_L b_L coupling, we show that the
electroweak symmetry of the standard model specifies the pattern of deviations
of the Z t_L t_L and W t_L b_L couplings, independent of underlying new physics
scenarios. We study implications of the predicted pattern with data on the
single top quark and Ztt associated production processes at the Large Hadron
Collider. Such an analysis could in principle allow for a determination of the
Wtb coupling without prior knowledge of |V_{tb}|, which is otherwise difficult
to achieve.
