NUNUGPV — A Monte Carlo event generator for e+e− → vv̄γ(γ) events at LEP Original Research Article

The Monte Carlo program NUNUGPV, designed for computing distributions and generating events for the reaction e+e− → vv̄γ(γ), is described. The lowest-order spectrum of the hard-scattering photon includes the contribution from both Z and W exchange within the electroweak theory and is convoluted with pt-dependent QED structure functions in order to explicitly generate the transverse degrees of freedom of the additional photons emitted by the colliding particles. The code is designed for a two-fold use: as a Monte Carlo integrator of weighted events, giving in output the total cross section; and as a true event generator, allowing for events with up-to-three exclusive photons.