Probing new gauge-boson couplings via three-body decays

We examine the possibility of using rare, three-body decays of a new neutral gauge boson Z2 to probe its gauge couplings at hadron colliders. Specifically, we study the decays Z2→Wlν and Z2→Zνν̄ and find that much knowledge of the Z2 properties can be obtained from these processes. In particular, these decay modes can yield valuable information on the amount of Z1-Z2 mixing, on the generation dependence of the Z2 couplings, and on the properties of the new generator associated with the Z2, as well as being used to distinguish between possible extended models. Standard model backgrounds to these three-body decays are discussed, and we find that the rate for pp→ZZ→Zνν̄ eclipses that of pp→Z2→Zνν̄ at hadron supercolliders. The analogous three-body decays into a new, heavy charged gauge boson, Z2→W2±lν, are also investigated in models where this can occur.