Constraints on quartic vector-boson interactions from Z physics

We obtain the constraints on possible anomalous quartic vector-boson vertices arising from the precision measurements at the Z pole. In the framework of SU(2)_L \otimes U(1)_Y chiral Lagrangians, we examine all effective operators of order D=4 that lead to four-gauge-boson interactions but do not induce anomalous trilinear vertices. We constrain the anomalous quartic interactions by evaluating their one-loop corrections to the Z pole physics. Our analysis is performed in a generic R_\xi gauge and it shows that only the operators that break the SU(2)_C custodial symmetry get limits close to the theoretical expectations. Our results also indicate that these anomalous couplings are already out of reach of the Next Linear e^+ e^- Collider, while the Large Hadron Collider could be able to further extend the bounds on some of these couplings.