New Interactions in Neutral Current Processes
  Measurements of neutral current processes off the $Z$-peak are sensitive probes of new interactions, which may be induced by the exchange of new particles such as leptoquarks or extra $Z$'s. This talk reviews the phenomenology of extra interactions in four-fermion processes and updates a global fit to contact terms in the neutral current sector. 
Dieter Zeppenfeld and Kingman Cheung