RADIATION OF LIGHT FERMIONS IN HEAVY-FERMION PRODUCTION

The rate for the production of a pair of massive fermions in e(+)e(-) annihilation plus real or virtual radiation of a pair of massless ferm ions is calculated analytically. The contributions for real and virtua l radiation are displayed separately. The asymptotic behaviour close t o threshold and for high energies is given in a compact form. These ap proximations provide arguments for the appropriate choice of the scale in the O(alpha) result, such that no large logarithms remain in the f inal answer.