2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/214791The fermion mass effects in e+ e- --> 4f and in the corresponding bremsstrahlung reactions in the presence of realistic cuts are studied. It is shown that, for some four--fermion final states, the mass effects become sizeable to the extent that they may affect the accuracy of theoretical predictions which is required to be better than 1%.8 pagesHigh Energy Physics - Phenomenologytext