INVISIBLE EVENTS WITH RADIATIVE PHOTONS AT LEP

A study of the radiative neutrino-counting reaction e(+)e(-) --> $($) over bar$$ vvy at LEP1 and LEP2 energies is presented. An approximate expression for the spectrum of the observed photon is derived within t he framework of the p(t)-dependent structure function approach, This i s compared with an exact expression and found to be in agreement withi n the foreseen experimental accuracy. This model describing single-pho ton radiation can be applied to the more general case of initial-state single-photon emission accompanying invisible final-state events. Hig her-order QED corrections due to undetected initial-state radiation ar e also included, The implementation in a Monte Carlo event generator i s briefly described.