Model independent constraints among the Wtb, Zbb̄, and Ztt̄ couplings

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, Ztt̄, and Zbb̄ couplings. After one imposes the known experimental constraint on the ZbLbL coupling, we show that the electroweak SU(2)L×U(1)Y symmetry of the standard model specifies the pattern of deviations of the ZtLtL and WtLbL couplings, independent of underlying new physics scenarios. We study implications of the predicted pattern with data on the single top quark and Ztt̄ 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 |Vtb|, which is otherwise difficult to achieve.