Quartic anomalous couplings at LEP

The search for quartic anomalous gauge couplings at LEP requires appropriat e predictions for the radiative processes e(+)e(-) --> nu<(<nu>)over bar>ga mma gamma, e(+)e(-) --> q (q) over bar gamma gamma and e(+)e(-) --> 4 fermi ons +gamma. Matrix elements are exactly computed at the tree level, and the effects of anomalous couplings and initial-state radiation are included. C omparisons with results and approximations existing in the literature are s hown and commented. Improved versions of the event generators NUNUGPV and W RAP are made available for experimental analysis. (C) 2001 Published by Els evier Science B.V.