ELECTROWEAK STUDIES AT Z FACTORIES

The Large Electron Positron collider LEP1 at CERN produced tens of millions of Z bosons, and the e⁺e⁻ linear collider SLC at SLAC has produced Z bosons with its polarized e⁻ beam. Along with the measurements of the top-quark and W-boson masses at the Fermilab Tevatron collider, these Z-factory experiments have tested the standard electroweak theory with unprecedented precision. This chapter reviews the renormalizable gauge theory of the electroweak interactions and its quantum-level tests. Implications of the precision measurements are then studied within the standard model and its extentions.