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 ⊗ 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 Rξ 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.