Four Fermion processes at LEP II

Abstract

In its second phase, LEP has given the unique opportunity to study four fermion processes never observed before. This papers deals with a preliminary study of $WW$, $We\nu$, $ZZ$ and $Z\gamma^\star$ production in $e^+e^-$ collisions. Measurement results on $WW$ cross section, $W$ branching fractions, $WWV$ ($V=Z/\gamma$) anomalous couplings and $W$ average polarization in $WW$ events are presented. Moreover cross section measurements for $We\nu$, $ZZ$ and $Z\gamma^\star$ production and limits on $ZZZ$ and $ZZ\gamma$ anomalous couplings are reported. All the results are in good agreement with the Standard Model expectations.